Title: Common Diseases of Farm Animals
Author: Craig, Robert Alexander, 1872-
Language: English
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COMMON DISEASES OF FARM ANIMALS

By R. A. Craig, D.V.M.

[Illustration: Frontispiece--INSANITARY DAIRY STABLE AND YARDS. DISEASE AND
FINANCIAL LOSS ARE TO BE EXPECTED WHEN FARM ANIMALS ARE KEPT IN FILTHY,
INSANITARY QUARTERS]



PREFACE

In preparing the material for this book, the author has endeavored to
arrange and discuss the subject matter in a way to be of the greatest
service and help to the agricultural student and stockman, and place at
their disposal a text and reference book.

The general discussions at the beginning of the different sections and
chapters, and the discussions of the different diseases are naturally
brief. An effort has been made to conveniently arrange the topics for both
practical and class-room work. The chapters have been grouped under the
necessary heads, with review questions at the end of each chapter, and the
book divided into seven parts.

The chapters on diseases of the locomotory organs, the teeth, surgical
diseases and castration, although not commonly discussed in books of this
class, the writer believes will be of value for reference and instructional
work.

When used as a text-book, it will be well for the instructor to supplement
the text with class-room discussions.

The writer has given special emphasis to the cause and prevention of
disease, and not so much to the medicinal treatment. Stockmen are not
expected to practise the medicinal treatment, but rather the preventive
treatment of disease. For this reason it is not deemed advisable to give a
large number of formulas for the preparation of medicinal mixtures to be
used for the treatment of disease, but such treatment is suggested in the
most necessary cases.

R. A. CRAIG.

PURDUE UNIVERSITY, LaFayette, Ind. August, 1915.



CONTENTS


PART I.--INTRODUCTORY.

I.      GENERAL DISCUSSION OF DISEASE
II.     DIAGNOSIS AND SYMPTOMS OF DISEASE
III.    TREATMENT

PART II.--NON-SPECIFIC OR GENERAL DISEASES.

IV.     DISEASES OF THE DIGESTIVE SYSTEM
V.      DISEASES OF THE LIVER
VI.     DISEASES OF THE URINARY ORGANS
VII.    DISEASES OF THE GENERATIVE ORGANS
VIII.   DISEASES OF THE RESPIRATORY APPARATUS
IX.     DISEASES OF THE CIRCULATORY ORGANS
X.      DISEASES OF THE NERVOUS SYSTEM
XI.     DISEASES OF THE SKIN
XII.    DISEASES OF THE EYE
XIII.   GENERAL DISEASES OF THE LOCOMOTORY APPARATUS
XIV.    STRUCTURE OF THE LIMBS OF THE HORSE
XV.     UNSOUNDNESSES AND BLEMISHES
XVI.    DISEASES OF THE FORE-LIMB
XVII.   DISEASES OF THE FOOT
XVIII.  DISEASES OF THE HIND LIMB

PART III.--THE TEETH.

XIX.    DETERMINING THE AGE OF ANIMALS
XX.     IRREGULARITIES OF THE TEETH

PART IV.--SURGICAL DISEASES.

XXI.    INFLAMMATION AND WOUNDS
XXII.   FRACTURES AND HARNESS INJURIES
XXIII.  COMMON SURGICAL OPERATIONS

PART V.--PARASITIC DISEASES.

XXIV.   PARASITIC INSECTS AND MITES
XXV.    ANIMAL PARASITES

PART VI.--INFECTIOUS DISEASES.

XXVI.   HOG-CHOLERA
XXVII.  TUBERCULOSIS
XXVIII. INFECTIOUS DISEASES COMMON TO THE DIFFERENT SPECIES OF DOMESTIC
          ANIMALS
XXIX.   INFECTIOUS DISEASES OF THE HORSE
XXX.    INFECTIOUS DISEASES OF CATTLE
XXXI.   INFECTIOUS DISEASES OF POULTRY

REFERENCE BOOKS



ILLUSTRATIONS

FIG.
(Frontispiece) Insanitary dairy stable and yards.
  1. Side and posterior view of bull showing conformation favorable to the
       development of disease.
  2. Insanitary yards.
  3. Showing where pulse of horse is taken.
  4. Auscultation of the lungs.
  5. Fever thermometer.
  6. Dose syringe.
  7. Hypodermic syringes.
  8. Photograph of model of horse's stomach.
  9. Photograph of model of stomach of ruminant.
 10. Oesophageal groove.
 11. Dilated stomach of horse.
 12. Rupture of stomach of horse.
 13. Showing the point where the wall of flank and rumen are punctured
       with trocar and cannula in "bloat".
 14. Photograph of model of digestive tract of horse.
 15. Photograph of model of digestive tract of ruminant.
 16. A yearling colt that died of aneurism colic.
 17. Photograph of model of udder of cow.
 18. Photograph of model of uterus of cow containing foetus.
 19. Placenta of cow.
 20. A case of milk-fever.
 21. Milk-fever apparatus.
 22. A case of catarrhal cold.
 23. Photograph of model of horse's heart.
 24. Elephantiasis in horse.
 25. Photograph of model of horse's brain.
 26. Unilateral facial paralysis.
 27. Bilateral facial paralysis.
 28. Skeleton of horse.
 29. Photograph of model of stifle joint.
 30. Atrophy of the muscles of the thigh.
 31. Shoulder lameness.
 32. Shoe-boil.
 33. Sprung knees.
 34. Splints.
 35. Bones of digit.
 36. Photograph of a model of the foot.
 37. Foot showing neglect in trimming wall.
 38. A very large side bone.
 39. A case of navicular disease.
 40. An improperly shod foot.
 41. Toe-cracks.
 42. Quarter-crack caused by barb-wire cut.
 43. Changes occurring in chronic laminitis.
 44. Atrophy of the muscles of the quarter.
 45. String-halt.
 46. A large bone spavin.
 47. Normal cannon bone and cannon bone showing bony enlargement.
 48. Bog spavins.
 49. Thorough pin.
 50. Curbs.
 51. Head of young horse showing position and size of teeth.
 52. Longitudinal section of incisor tooth.
 53. Cross-section of head of young horse, showing replacement of molar
       tooth.
 54. Transverse section of incisor tooth
 55. Transverse sections of incisor tooth showing changes at different
       ages.
 56. Teeth showing uneven wear occurring in old horses.
 57. Fistula of jaw.
 58. A large hock caused by a punctured wound of the joint.
 59. A large inflammatory growth following injury.
 60. Fistula of the withers.
 61. Shoulder abscess caused by loose-fitting harness.
 62. A piece of the wall of the horse's stomach showing bot-fly larvae
       attached.
 63. Biting louse.
 64. Sucking louse.
 65. Nits attached to hair.
 66. Sheep-tick.
 67. Sheep scab mite.
 68. Sheep scab.
 69. A severe case of mange.
 70. Liver flukes.
 71. Tapeworm larvae in liver.
 72. Tapeworms.
 73. Tapeworm larvae in the peritoneum.
 74. Thorn-headed worms.
 75. Large round-worm in intestine of hog.
 76. Lamb affected with stomach worm disease.
 77. Whip-worms attached to wall of intestine.
 78. Pin-worms in intestine.
 79. A hog yard where disease-producing germs may be carried over
       from year to year.
 80. Carcass of a cholera hog.
 81. Kidneys from hog that died of acute hog-cholera.
 82. Lungs from hog that died of acute hog-cholera.
 83. A piece of intestine showing intestinal ulcers.
 84. Cleaning up a hog lot.
 85. Hyperimmune hogs used for the production of anti-hog-cholera serum.
 86. Preparing the hog for vaccination.
 87. Vaccinating a hog.
 88. Koch's _Bacillus tuberculosis_.
 89. A tubercular cow.
 90. Tubercular spleens.
 91. The carcass of a tubercular cow.
 92. A section of the chest wall of a tubercular cow.
 93. A very large tubercular gland.
 94. A tubercular gland that is split open.
 95. Caul showing tuberculosis.
 96. Foot of hog showing tuberculosis of joint.
 97. _Staphylococcus pyogenes_.
 98. _Streptococcus pyogenes_.
 99. Bacillus of malignant oedema, showing spores.
100. Bacillus of malignant oedema.
101. _Bacillus bovisepticus_.
102. A yearling steer affected with septicaemia haemorrhagica.
103. _Bacillus anthracis_.
104. _Bacillus necrophorus_.
105. Negri bodies in nerve-tissue.
106. A cow affected with foot-and-mouth disease.
107. Slaughtering a herd of cattle affected with foot-and-mouth disease.
108. Disinfecting boots and coats before leaving a farm where cattle have
       been inspected for foot-and-mouth disease.
109. Cleaning up and disinfecting premises.
110. _Bacillus tetani_.
111. Head of horse affected with tetanus.
112. A subacute case of tetanus.
113. Streptococcus of strangles.
114. _Bacillus mallei_.
115. Nasal septum showing nodules and ulcers.
116. _Streptococcus pyogenes equi_.
117. A case of "lumpy jaw".
118. The ray fungus.
119. Bacillus of emphysematous anthrax.
120. Cattle tick (male).
121. Cattle tick (female).
122. Blood-cells with _Piroplasma bigeminum_ in them.
123. _Bacillus avisepticus_.



PART I.--INTRODUCTORY


CHAPTER I

GENERAL DISCUSSION OF DISEASE


Disease is the general term for any deviation from the normal or healthy
condition of the body. The morbid processes that result in either slight or
marked modifications of the normal condition are recognized by the
injurious changes in the structure or function of the organ, or group of
body organs involved. The increase in the secretion of urine noticeable in
horses in the late fall and winter is caused by the cool weather and the
decrease in the perspiration. If, however, the increase in the quantity of
urine secreted occurs independently of any normal cause and is accompanied
by an unthrifty and weakened condition of the animal, it would then
characterize disease. Tissues may undergo changes in order to adapt
themselves to different environments, or as a means of protecting
themselves against injuries. The coat of a horse becomes heavy and appears
rough if the animal is exposed to severe cold. A rough, staring coat is
very common in horses affected by disease. The outer layer of the skin
becomes thickened when subject to pressure or friction from the harness.
This change in structure is purely protective and normal. In disease the
deviation from normal must be more permanent in character than it is in the
examples mentioned above, and in some way prove injurious to the body
functions.

CLASSIFICATION.--We may divide diseases into three classes: _non-specific,
specific_ and _parasitic_.

_Non-specific diseases_ have no constant cause. A variety of causes may
produce the same disease. For example, acute indigestion may be caused by a
change of diet, watering the animal after feeding grain, by exhaustion and
intestinal worms. Usually, but one of the animals in the stable or herd is
affected. If several are affected, it is because all have been subject to
the same condition, and not because the disease has spread from one animal
to another.

_Specific Diseases._--The terms infectious and contagious are used in
speaking of specific diseases. Much confusion exists in the popular use of
these terms. A _contagious_ disease is one that may be transmitted by
personal contact, as, for example, influenza, glanders and hog-cholera. As
these diseases may be produced by indirect contact with the diseased animal
as well as by direct, they are also _infectious_. There are a few germ
diseases that are not spread by the healthy animals coming in direct
contact with the diseased animal, as, for example, black leg and southern
cattle fever. These are purely infectious diseases. Infection is a more
comprehensive term than contagion, as it may be used in alluding to all
germ diseases, while the use of the term contagion is rightly limited to
such diseases as are produced principally through individual contact.

_Parasitic diseases_ are very common among domestic animals. This class of
disease is caused by insects and worms, as for example, lice, mites, ticks,
flies, and round and flat worms that live at the expense of their hosts.
They may invade any of the organs of the body, but most commonly inhabit
the digestive tract and skin. Some of the parasitic insects, mosquitoes,
flies and ticks, act as secondary hosts for certain animal microorganisms
that they transmit to healthy individuals through the punctures or the
bites that they are capable of producing in the skin.

CAUSES.--For convenience we may divide the causes of disease into the
predisposing or indirect, and the exciting or direct.

_The predisposing causes_ are such factors as tend to render the body more
susceptible to disease or favor the presence of the exciting cause. For
example, an animal that is narrow chested and lacking in the development of
the vital organs lodged in the thoracic cavity, when exposed to the same
condition as the other members of the herd, may contract disease while the
animals having better conformation do not (Fig. 1). Hogs confined in
well-drained yards and pastures that are free from filth, and fed in pens
and on feeding floors that are clean, do not become hosts for large numbers
of parasites. Hogs confined in filthy pens are frequently so badly infested
with lice and intestinal worms that their health and thriftiness are
seriously interfered with. In the first case mentioned the predisposition
to disease is in the individual, and in the second case it is in the
surroundings (Fig. 2).

[Illustration: FIG. 1.--Side and posterior view of bull showing
conformation favorable to the development of disease.]

_The exciting causes_ are the immediate causes of the particular disease.
Exciting causes usually operate through the environment. With the exception
of the special disease-producing germs, the most common exciting causes are
faulty food and faulty methods of feeding. The following predisposing
causes of disease may be mentioned:

_Age_ is an important factor in the production of disease. Young and
immature animals are more prone to attacks of infectious diseases than are
old and mature animals. Hog-cholera usually affects the young hogs in the
herd first, while scours, suppurative joint disease and infectious sore
mouth are diseases that occur during the first few days or few weeks of the
animal's life. Lung and intestinal parasites are more commonly found in the
young, growing animals. Old animals are prone to fractures of bones and
degenerative changes of the body tissues. As a general rule, the young are
more subject to acute diseases and the old to chronic diseases.

[Illustration: FIG. 2.--Insanitary yards.]

_The surroundings or environments_ are important predisposing factors. A
dark, crowded, poorly ventilated stable lowers the animal's vitality, and
renders it more susceptible to the disease. A few rods difference in the
location of stables and yards may make a marked difference in the health of
the herd. A dry, protected site is always preferable to one in the open or
on low, poorly drained soil. The majority of domestic animals need but
little shelter, but they do need dry, comfortable quarters during wet, cold
weather.

_Faulty feed and faulty methods of feeding_ are very common causes of
diseases of the digestive tract and the nervous system. A change from dry
feed to a green, succulent ration is a common cause of acute indigestion in
both horses and cattle. The feeding of a heavy ration of grain to horses
that are accustomed to exercise, during enforced rest may cause liver and
kidney disorders. The feeding of spoiled, decomposed feeds may cause
serious nervous and intestinal disorders.

_One attack of a certain disease_ may influence the development of
subsequent attacks of the same, or a different disease. An individual may
suffer from an attack of pneumonia that so weakens the disease-resisting
powers of the lungs as to result in a tubercular infection of these organs.
In the horse, one attack of azoturia predisposes it to a second attack. One
attack of an infectious disease usually confers immunity against that
particular disease. _Heredity_ does not play as important a part in the
development of diseases in domestic animals as in the human race. A certain
family may inherit a predisposition to disease through the faulty or
insufficient development of an organ or group of organs. The different
species of animals are affected by diseases peculiar to that particular
species. The horse is the only species that is affected with azoturia.
Glanders affects solipeds, while black leg is a disease peculiar to cattle.


QUESTIONS

1. What is disease?

2. How are diseases classified? Give an example of the different classes.

3. What is a predisposing cause? Exciting cause?

4. Name the different predisposing and exciting causes of disease.



CHAPTER II

DIAGNOSIS AND SYMPTOMS OF DISEASE


The importance of recognizing or diagnosing the seat and nature of the
morbid change occurring in an organ or group of organs cannot be
overestimated. Laymen do not comprehend the difficulty or importance of
correctly grouping the signs or symptoms of disease in such a way as to
enable them to recognize the nature of the disease. In order to be able to
understand the meaning of the many symptoms or signs of disease, we must
possess knowledge of the structure and physiological functions of the
different organs of the body. We must be familiar with the animal when it
is in good health in order to be able to recognize any deviation from the
normal due to disease, and we must learn from personal observation the
different symptoms that characterize the different diseases. Stockmen
should be able to tell when any of the animals in their care are sick as
soon as the first symptom of disease manifests itself, by changes in the
general appearance and behavior. But in order to ascertain the exact
condition a general and systematic examination is necessary. The examiner,
whether he be a layman or a veterinarian, must observe the animal
carefully, noting the behavior, appearance, surroundings, and general and
local symptoms.

Before making a _general examination_ of the animal it is well, if the
examiner is not already acquainted with the history of the case (care, feed
and surroundings), to learn as much about this from the attendant as is
possible. Inquiry should be made as to the feeding, the conditions under
which the animal has been kept, the length of time it has been sick, its
actions, or any other information that may be of assistance in forming the
diagnosis and outlining the treatment.

The _general symptoms_ inform us regarding the condition of the different
groups of body organs. A careful study of this group of symptoms enables us
correctly to diagnose disease and inform ourselves as to the progress of
long, severe affections. These symptoms occur in connection with the pulse,
respirations, body temperature, skin and coat, visible mucous membranes,
secretions and excretions, and behavior of the animal.

_The local symptoms_ are confined to a definite part or organ. Swelling,
pain, tenderness and loss of function are common local symptoms. A _direct_
symptom may also be considered under this head because of its direct
relation to the seat of disease. It aids greatly in forming the diagnosis.

Other terms used in describing symptoms of disease are _objective_, which
includes all that can be recognized by the person making the examination;
_indirect_, which are observed at a distance from the seat of the disease;
and _premonitory_, which precede the direct, or characteristic symptoms.
The _subjective_ symptoms include such as are felt and described by the
patient. These symptoms are available from the human patient only.

Pulse.--The character of the intermittent expansion of the arteries, called
the pulse, informs us as to the condition of the heart and blood-vessels.
The frequency of the pulse beat varies in the different species of animals.
The smaller the animal the more frequent the pulse. In young animals the
number of beats per minute is greater than in adults. Excitement or fear,
especially if the animal possesses a nervous temperament, increases the
frequency of the pulse. During, and for a short time after, feeding and
exercise, the pulse rate is higher than when the animal is standing at
rest.

The following table gives the normal rate of the pulse beats per minute:

Horse  36 to  40 per minute
Ox     45 to  50 per minute
Sheep  70 to  80 per minute
Pig    70 to  80 per minute
Dog    90 to 100 per minute

In sickness the pulse is instantly responsive. It is of the greatest aid
in diagnosing and in noting the progress of the disease. The following
varieties of pulse may be mentioned: _frequent, infrequent, quick, slow,
large, small, hard, soft_ and _intermittent_. The terms frequent and
infrequent refer to the number of pulse beats in a given time; quick and
slow to the length of time required for the pulse wave to pass beneath the
finger; large and small to the volume of the wave; hard and soft to its
compressibility; and intermittent to the occasional missing of a beat. A
pulse beat that is small and quick, or large and soft, is frequently met
with in diseases of a serious character.

[Illustration: FIG. 3.--The X on the lower border of the jaw indicates the
place where the pulse is taken.]

_The horse's pulse_ is taken from the submaxillary artery at a point
anterior to, or below the angle of the jaw and along its inferior border
(Fig. 3). It is here that the artery winds around the inferior border of
the jaw in an upward direction, and, because of its location immediately
beneath the skin, it can be readily located by pressing lightly over the
region with the fingers.

_Cattle's pulse_ is taken from the same artery as in the horse. The artery
is most superficial a little above the border of the jaw. It is more
difficult to find the pulse wave in cattle than it is in horses, because of
the larger amount of connective tissue just beneath the skin and the
heavier muscles of the jaw. A very satisfactory pulse may be found in the
small arteries located along the inferior part of the lateral region of the
tail and near its base.

_The sheep's pulse_ may be taken directly from the femoral artery by
placing the fingers over the inner region of the thigh. By pressing with
the hand over the region of the heart we may determine its condition.

_The hog's pulse_ can easily be taken from the femoral artery on the
internal region of the thigh. The artery crosses this region obliquely and
is quite superficial toward its anterior and lower portion.

_The dog's_ pulse is usually taken from the brachial artery. The pulse wave
can be readily felt by resting the fingers over the inner region of the arm
and just above the elbow. The character of the heart beats in dogs may be
determined by resting the hand on the chest wall.

RESPIRATION.--The frequency of the respirations varies with the species.
The following table gives the frequency of the respirations in domestic
animals:

Horse    8 to 10 per minute
Ox      12 to 15 per minute
Sheep   12 to 20 per minute
Dog     15 to 20 per minute
Pig     10 to 15 per minute

The ratio of the heart beats to the respirations is about 1:4 or 1:5. This
ratio is not constant in ruminants. Rumination, muscular exertion and
excitement increase the frequency and cause the respirations to become
irregular. In disease the ratio between the heart beats and respirations
is greatly disturbed, and the character of the respiratory sounds and
movements may be greatly changed (Fig. 4).

[Illustration: FIG. 4.--Auscultation of the lungs can be practised to an
advantage over the outlined portion of the chest wall, only.]

Severe exercise and diseased conditions of the lungs cause the animal to
breathe rapidly and bring into use all of the respiratory muscles. Such
forced or labored breathing is a common symptom in serious lung diseases,
"bloat" in cattle, or any condition that may cause dyspnoea. Horses
affected with "heaves" show a double contraction of the muscles in the
region of the flank during expiration. In spasm of the diaphragm or
"thumps" the expiration appears to be a short, jerking movement of the
flank. In the abdominal form of respiration the movements of the walls of
the chest are limited. This occurs in pleurisy. In the thoracic form of
respiration the abdominal wall is held rigid and the movement of the chest
walls make up for the deficiency. This latter condition occurs in
peritonitis.

_A cough_ is caused by irritation of the membrane lining the air passages.
The character of the cough may vary according to the nature of the disease.
We may speak of a moist cough when the secretions in the air passages are
more or less abundant. A dry cough occurs when the lining membrane of the
air passages is dry and inflamed. This may occur in the early stage of the
inflammation, or as a result of irritation from dust or irritating gases.
Chronic cough occurs when the disease is of long duration or chronic. In
pleurisy the cough may be short and painful, and in broken wind, deep and
suppressed. In parasitic diseases of the air passages and lungs, the
paroxysm of coughing may be severe and "husky" in character.

The odor of the expired air, the character of the discharge and the
respiratory sounds found on making a careful examination are important aids
in arriving at a correct diagnosis, and in studying the progress of the
disease.

[Illustration: FIG. 5.--Fever thermometer.]

Body Temperature.--The body temperature of an animal is taken by inserting
the fever thermometer into the rectum. In large animals a five-inch, and in
small animals a four-inch fever thermometer is used. It should be inserted
full length and left in position from one and one-half to three minutes,
depending on the rapidity with which it registers (Fig. 5).

The average normal body temperatures of domestic animals are as follows:

Horses  100.5\260 F.
Cattle  101.4\260 F.
Sheep   104.0\260 F.
Swine   103.0\260 F.
Dog     101.4\260 F.

There is a wide variation in the body temperatures of domestic
animals. This is especially true of cattle, sheep and hogs. In order to
determine the normal temperature of an animal, it may be necessary to take
two or more readings at different times, and compare them with the body
temperatures of other animals in the herd that are known to be healthy.

Exercise, feeding, rumination, excitement, warm, close stables, exposure to
cold and drinking ice cold water are common causes of variations in the
body temperatures of domestic animals.

Visible Mucous Membranes.--The visible mucous membranes, as they are
termed, are the lining membranes of the eyelids, nostrils and nasal
cavities, and mouth. In health they are usually a pale red, excepting when
the animal is exercised or excited, when they appear a brighter red and
somewhat vascular. In disease the following changes in color and appearance
may be noted: When inflamed, as in cold in the head, a deep red; in
impoverished or bloodless conditions of the body and in internal
haemorrhage, pale; in diseases of the liver, sometimes yellowish, or dark
red; in diseases of the digestive tract (buccal mucous membrane), coated;
if inflamed, dry at first, later excessively moist; and in certain germ
diseases a mottled red, or showing nodules, ulcers and scars.

Surface of the Body.--When a horse is in a good condition and well cared
for, the coat is short, fine, glossy and smooth and the skin pliable and
elastic. Healthy cattle have a smooth, glossy coat and the skin feels
mellow and elastic. The fleece of sheep should appear smooth and have
plenty of yolk, the skin pliable and light pink in color. When the coat
loses its lustre and gloss and the skin becomes hard, rigid, thickened and
dirty, it indicates a lack of nutrition and an unhealthy condition of the
body. In sheep, during sickness, the wool may become dry and brittle and
the skin pale and rigid. When affected with external parasites, the hair or
wool becomes dirty and rough, a part of the skin may be denuded of hair,
and it appears thickened, leathery and scabby, or shows pimples, vesicles
and sores.

During fever, the temperature of the surface of the body is very unequal.
In serious diseases or diseases that are about to terminate fatally, the
skin feels cold and the hair is wet with sweat.

When animals are allowed to "rough it" during the cold weather, the coat of
hair becomes heavy and rough. This is a provision of nature and enables
them, as long as the coat is dry, to withstand severe cold.

Horses that are in a low physical condition, or when accustomed to hard
work, if then kept in a stall for a few days without exercise, commonly
show a filling of the cannon regions of the posterior extremities. This
condition also commonly occurs in disease and in mares that have reached
the latter period of pregnancy. Sheep that are unthrifty and in a poor
physical condition, especially if this is due to internal parasites,
frequently develop dropsical swellings in the region of the jaw, or neck.

Body Excretions.--The character of the body excretions, faeces and urine
may become greatly changed in certain diseases. It is important that the
stockman or veterinarian observe these changes, and in certain diseases
make an analysis of the urine. This may be necessary in order properly to
diagnose the case.

Behavior of the Animal.--When the body temperature is high, the animal may
appear greatly depressed. If suffering severe pain, it may be restless. In
diseases of the nervous system, the behavior of the animal may be greatly
changed. Spasms, convulsions, general local paralysis, stupid condition and
unconsciousness may occur as symptoms of this class of disease.


QUESTIONS

1. What information is necessary in order to be able to recognize or
   diagnose disease? 2. What are the general symptoms of disease?

3. What are the subjective symptoms of disease?

4. Describe method of taking the pulse beat in the different animals and
   its character in health and disease.

5. Give the ratio of the heart beats to the respirations in the different
   species of animals.

6. What are the normal body temperatures in the different domestic animals?

7. What are the visible mucous membranes?

8. Is the condition of the coat and skin any help in the recognition of
   disease?



CHAPTER III

TREATMENT


Preventive Treatment.--The subject of preventive medicine becomes more
important as our knowledge of the cause of disease advances. A knowledge of
feeds, methods of feeding, care, sanitation and the use of such biological
products as bacterins, vaccines and protective serums is of the greatest
importance to the farmer and veterinarian. We are beginning to realize that
one of the most important secrets of profitable and successful stock
raising is the prevention of disease; that the agricultural colleges are
doing a great work in helping to teach farmers that there are right and
wrong methods of feeding and caring for animals; that the practice of
sanitation in caring for animals is the cheapest method of treating
disease; and that it is advisable to practise radical methods of control,
when necessary, in order to rid the herd of an infectious disease.

_The ration fed_ and the method of feeding are not only important in
considering the causes of diseases of the digestive tract, but diseases of
other organs as well. The feeding of an excessive, or insufficient quantity
of feed, or a ration that is too concentrated, bulky and innutritious, poor
in quality, or spoiled may produce disease.

_An impure water supply_ is a common cause of disease. A deep well that is
closed in properly and does not permit of contamination from filth, does
not insure a clean water supply if the trough or tank is not kept clean.

_Farm Buildings_.--If stockmen would make a more careful study of the kind
of farm buildings most suitable to their needs, the selection of the
location, the proportions, the arrangement of the interior and the lighting
and ventilation, there would be a great saving in losses from disease, and
the cost of building in many cases would be lessened. Your neighbor's
building that you have taken for your model may not be suitable for your
needs. It may be more expensive than your financial condition permits. It
may be poorly lighted and ventilated and not suited to the site that you
have selected.

_Biological Products_.--There are a number of biological products that may
be used in the prevention and control of disease. Some of these products,
such as tuberculin and malein, enable the owner to rid his herds of
tubercular cows and glandered horses before these diseases have become far
enough advanced to be recognized by the visible symptoms alone. Black leg,
anthrax and hog-cholera vaccines are valuable agents in the control of
disease. In the treatment of fistula and infectious abortion, bacterins may
be used. There are many other germ diseases and infections for which
vaccines and bacterins may be used. However, we must not depend wholly on
these agents in the control of disease. We must possess a knowledge of the
manner in which the infection is spread, for without this knowledge we
would be unable to prevent its dissemination over a wide area.

Medicinal Treatment.--The average stockman or veterinarian is more familiar
with the treatment of disease with drugs than he is with the preventive
measures just described. This statement does not imply that a knowledge of
medicinal therapeutics is not of the greatest importance in the treatment
of disease. The ultimate object of all drugs is both to prevent and cure
disease, but the injudicious use of a drug does neither. A discussion of
this subject cannot be entered into here, and because of its largeness it
is not advisable to discuss it further than a brief summary of the methods
of administering drugs.

Administration of Drugs.--Drugs may be administered by the following
channels: by way of the mouth, in the feed or as a drench; by injecting
into the tissues beneath the skin or hypodermically; by rubbing into the
skin; by the air passages and the lungs; and by injecting into the rectum.

If the animal is not too sick to eat and the drug does not possess an
unpleasant taste, it may be given with the feed. If soluble, it may be
given with the drinking water, or in any case, it may be mixed with ground
feed if this method is to be preferred. In all cases the medicine must be
well mixed with the feed. This is especially important if there are a
number of animals to be treated, as there is more certainty of each animal
getting the proper dose and the danger of overdosing is avoided. If the
young animal is nursing the mother, we can take advantage of certain drugs
being eliminated in the mother's milk and administer the drug to the
mother.

[Illustration: FIG. 6.--A good kind of a dose syringe.]

DRENCHES.--In the larger animals a bulky drench is sometimes difficult to
administer, and we should, in all cases, count on a portion being wasted.

_Horses_ are sometimes difficult to drench, and it may be advisable to
confine the horse in some way. Small drenches can readily be given with a
syringe (Fig. 6) or a small bottle. In giving bulky drenches it is most
convenient to use a long-necked, heavy glass bottle. The horse should be
backed into a narrow stall and the head elevated by placing a loop in the
end of a small rope over the upper jaw, passing the rope back of the nose
piece on the halter and throwing it over a beam, and raising the head until
the mouth is slightly higher than the throat. If the horse refuses to
swallow, a tablespoonful of clean water may be dropped into the nostril.
This forces it to swallow. A drench should never be given through the nose,
as it may pass into the air passages and cause a fatal inflammation of the
lungs.

_Cattle_ can be easily drenched by taking hold of the nostrils with the
fingers, or snapping a bull ring into the partition between the nostrils
and elevating the head.

_Sheep_ may be drenched either in the standing position, or when thrown on
the haunches and held between the knees. Care should be exercised in giving
irritating drenches to sheep, especially if the drench be bulky.

_A herd of hogs_ may be quickly and easily drenched if they are confined in
a small pen, and the loop of a small rope placed around the snout, well
back toward the corners of the mouth. A small metal dose syringe should be
used. If the drench is bulky and the hog difficult to hold, it may be
necessary to elevate the head and raise the forefeet from the ground. The
drench should not be given until the hog is quiet and well under control,
as there is some danger of the medicine passing into the air passages and
doing harm. It may be necessary to mark the hogs that have been drenched
with a daub of paint, or in some other manner in order to be able to
distinguish them from the untreated animals.

The administration of drugs enclosed in a gelatin capsule, or mixing them
with syrup, honey or linseed oil, and rolling the mass into the form of a
cylinder is commonly practised. The _capsule_ or _ball_ may then be shot
into the pharynx with a balling gun. A ball may also be given to the larger
animals by carrying it into the back part of the mouth with the hand, and
placing it on the back part of the tongue. In the horse this method of
administration requires some practice. The tongue must be pulled well
forward, the head held up, and the tongue released as soon as the ball is
placed on the tongue, so that it may pass back into the pharynx.

The administration of drugs by _injecting beneath the skin_ (Fig. 7) is
suitable when the drug is non-irritating and the dose is small. Drugs
administered in this way act promptly and energetically. The alkaloid or
active principle of the drug is commonly used. A fold of the skin is picked
up with the fingers and the needle is quickly introduced, care being taken
not to prick or scratch the muscular tissue, as this causes some pain and
makes the animal restless. In order to avoid abscess formation at the point
of injection, the skin should be cleansed with a disinfectant and the
syringe and needle sterilized before using.

[Illustration: FIG. 7.--Hypodermic syringes.]

Drugs are not absorbed through the unbroken skin, but when applied with
friction, or when the outer layer is removed by blistering, absorption may
take place. Liniments, blisters and _poultices_ are the preparations used.

_Volatile drugs_, such as chloroform and ether, are absorbed quickly by the
enormous vascular surface of the lungs. This class of drugs is administered
for the purpose of producing general anaesthesia. _Anaesthetics_ are
indispensable in many surgical operations.

The administration of a drug in the form of _medicated steam_ is quite
useful in combating some respiratory diseases. In steaming large animals a
pail about half full of boiling-hot water to which has been added about an
ounce of coal-tar disinfectant, or whatever drug is required, is held
within about one foot of the animal's nostrils. It is usually advisable to
throw a light cover over the head and pail in order to direct the steam
toward the nostrils. Dogs can be placed on a cane-seated chair and a pail
or pan of boiling-hot water placed under it, and a sheet thrown over all.

Drugs are administered by way of the rectum when the animal can not be
drenched, or the drug can not be given in any other way and when a local
action is desired. An _enema_ or _clyster_ is a fluid injection into the
rectum and is employed for the following purposes: to accelerate the action
of a purgative; to stimulate the peristaltic movement of the intestines; to
kill intestinal parasites; to reduce body temperature; to administer
medicine; and to supply the animal with food. An enema may be administered
by allowing water to gravitate into the rectum from a height of two or
three feet or by using an injection pump. In the larger animals several
feet of heavy walled rubber tubing carrying a straight nozzle at one end
should be used. In administering an enema, the rectum should be emptied out
with the hand and the nozzle of the syringe carried as far forward as
possible. The operator should be careful not to irritate or tear the wall
of the rectum.

Size of the Dose.--The doses recommended in the treatment of the different
diseases, unless otherwise stated, are for mature animals. The dose for a
colt one year of age is about one-third the quantity given the adult, two
years of age one-half, and three years of age two-thirds. In well-matured
colts a larger dose may be given. In cattle, the doses recommended are
about the same. In the smaller animals the size of the dose may be based on
the development and age of the animal. When the drug is administered at
short intervals or repeated, the size of the dose should be reduced. The
physiological action of some drugs may be changed by varying the size of
the dose.


QUESTIONS

1. Give a general description of preventive treatment.

2. By what channels may drugs be administered?

3. How are drenches administered?

4. How are solid drugs administered?

5. What kind of drugs are administered hypodermically?

6. What is an enema?

7. What proportion of the dose of a drug recommended for the adult may be
   given to immature animals?



PART II.--NON-SPECIFIC OR GENERAL DISEASES



CHAPTER IV

DISEASES OF THE DIGESTIVE SYSTEM


The organs that form the digestive tract are the mouth, pharynx,
oesophagus, stomach, intestines and the annexed glands, viz.: the salivary,
liver, and pancreas. The development of these organs differs in the
different species of animals. For example, solipeds possess a small, simple
stomach and capacious, complicated intestines. Just the opposite is true of
ruminants. The different species of ruminants possess a large, complicated
stomach, and comparatively simple intestines. In swine we meet with a more
highly developed stomach than that of solipeds and a more simple intestinal
tract. Of all domestic animals the most simple digestive tract occurs in
the dog. These variations in the development of the different organs of
digestion, together with the difference in the character of the feed and
method of feeding, cause a variation in the kind of diseases met with in
the different species. The complicated stomach of ruminants predispose them
to diseases of this portion of the digestive tract. Because of their
complicated intestinal tract solipeds are prone to intestinal disease.

DISEASES OF THE MOUTH

GENERAL DISCUSSION.--The mouth is the first division of the digestive
tract. It is formed by the lips, cheeks, palate, soft palate, tongue and
teeth. Here the feed is acted on mechanically. It is broken up by the teeth
and moved about until mixed with the saliva and put into condition to pass
through the pharynx and along the oesophagus to the stomach. The mechanical
change that the feed is subject to is very imperfect in dogs. In the horse
it is a slow, thorough process, although greedy feeders are not uncommon.
The first mastication in the ox is three times quicker than in horses, but
the process of rumination is slow and thorough.

STOMATITIS.--Simple inflammation of the mouth is frequently met with in
horses. Ulcerative or infectious inflammation commonly occurs in young, and
occasionally in old, debilitated animals. This form of sore mouth will be
discussed along with other infectious diseases, and the following
discussion will be confined to the non-infectious form of the disease.

_The causes_ are irritation from the bit, sharp teeth, irritating drenches,
roughage that contains beards or awns of grasses and grains, and burrs that
wound the lining membrane of the mouth. Febrile, or digestive disorders, or
any condition that may interfere with feeding, may cause this disorder. In
the latter cases the mucous membrane of the mouth is not cleansed by the
saliva. Particles of feed may decompose and irritating organisms set up an
inflammation. Putrid or decomposed slops, hot feeds, irritating drenches
and drinking from filthy wallows are common causes of inflammation of the
mouth in hogs.

_The symptoms_ vary in the different cases and species. Slight or localized
inflammation of the mouth is usually overlooked by the attendant. Lampas of
horses may be considered a local inflammation involving the palate.
Lacerations of the cheek or tongue by the teeth, or irritating feed,
usually result in a slight interference with prehension and mastication and
more or less salivation. Salivation from this cause should not be confused
with salivation resulting from feeding on white clover.

In generalized inflammation of the mucous membrane, the first symptom
usually noticed is the inability to eat. On examining the mouth we find the
mucous membrane inflamed, hot and dry. A part may appear coated. In a short
time the odor from the mouth is fetid. Following this dry stage of the
inflammation is the period of salivation. Saliva dribbles from the mouth,
and in severe cases it is mixed with white, stringy shreds of epithelium
and tinged with blood. In less acute forms of the disease, we may notice
little blisters or vesicles scattered over the lining membrane of the lips,
cheeks and tongue.

The acute form of stomatitis runs a short course, usually a few days, and
responds readily to treatment. Localized inflammation caused by irritation
from teeth, or feeding irritating feeds, does not respond so readily to
treatment.

_The treatment_ is largely preventive and consists largely in removing the
cause. When the mouth is inflamed, roughage should be fed rather sparingly,
and soft feeds such as slops, mashes, or gruels given in place of the
regular diet. Plenty of clean drinking water should be provided. In the way
of medicinal treatment antiseptic and astringent washes are indicated. A
four per cent water solution of boric acid may be used, or a one-half per
cent water solution of a high grade coal-tar disinfectant. The mouth should
be thoroughly irrigated twice daily until the mucous surfaces appear
normal.

DEPRAVED APPETITE

A depraved appetite is met with in all species of farm animals, but it is
especially common in ruminants. It should not be classed as a disease, but
more correctly as a bad habit, or symptom of innutrition or indigestion.
The animals affected seem to have an irresistible desire to lick, chew and
swallow indigestible and disgusting objects.

_The common cause_ of depraved appetite is the feeding of a ration
deficient in certain food elements. A ration deficient in protein or in
salts is said to cause this disorder. Lack of exercise, or confinement,
innutrition, and a depraved sense of taste may favor the development of
this disease. For example, when sheep are housed closely they may contract
the habit of chewing one another's fleeces. Lambs are especially apt to
contract this habit when suckling ewes that have on their udders long wool
soiled with urine and faeces.

_The first symptom_ is the desire to chew, lick or eat indigestible or
filthy substances. Horses and cattle may stand and lick a board for an hour
or more; cattle may chew the long hair from the tails of horses; sheep may
nibble wool; sows may within a short time after giving birth to their pigs,
kill and eat them; chickens may pick and eat feathers. Innutrition may
accompany the abnormal appetite, as very frequently the affected animal
shows a disposition to leave its feed in order to eat these injurious and
innutritions substances. In ruminants, the wool or hair may form balls and
obstruct the opening into the third compartment, causing chronic
indigestion and death.

_The treatment_ consists in the removal of the cause. Feeding a ration that
meets the needs of the system, clean quarters and plenty of exercise are
the most important preventive lines of treatment. In such cases medicinal
treatment (saline and bitter tonics) may be indicated. It is usually
advisable to remove the affected animals from the herd or flock in order to
prevent others from imitating them.

DISEASES OF THE STOMACH

There is a remarkable difference in the development of the stomachs of
solipeds and ruminants.

The horse's stomach (Fig. 8) is simple and has a capacity of three or four
gallons. The left portion is lined with a cuticular mucous membrane, and
the right portion with a glandular mucous membrane that has in it the
glands that secrete the gastric juice. The most important digestive change
in the feed is the action of the gastric juice on the proteids and their
conversion into the simpler products, proteoses and peptones.

[Illustration: FIG. 8.--Photograph of model of horse's stomach: left
portion, oesophagus, right portion, and intestine.]

[Illustration: FIG. 9.--Photograph of model of stomach of ruminant: rumen,
reticulum, omasum, and abomasum.]

[Illustration: FIG. 10.--A section of the wall of the rumen and reticulum,
showing the oesophageal groove: lips of groove; opening from
oesophagus; and opening into omasum.]

RUMINANTS have a compound stomach (Figs. 9 and 10). The capacity of the
stomach of the ox is between twenty and thirty gallons. The four
compartments into which it is divided are the rumen, reticulum, omasum, and
abomasum or true stomach. The rumen is the largest compartment, with a
capacity of more than twenty gallons. The reticulum is the smallest, with a
capacity of about one-half gallon.

After a brief mastication, the food passes directly to the _rumen_. Here it
is subjected to a churning movement that mixes and presses the contents of
the rumen forward in the direction of the oesophageal opening, where it is
ready for regurgitation. It is then carried back to the mouth, remasticated
and returned to the rumen. This is termed rumination. All food material
that is sufficiently broken up is directed toward the opening into the
third compartment by the oesophageal grove (Fig. 10), a demi-canal that
connects this with the oesophageal opening.

The third compartment, the _omasum_, communicates anteriorly with the
second and first, and posteriorly with the fourth compartment or true
stomach. The interior arrangement of this compartment is most singular. It
is divided by a number of large folds of the lining membrane between which
are smaller folds. It is between these folds that the contents pass.

The first three compartments possess no glands capable of secreting a
digestive juice. However, important digestive changes occur. The
carbohydrates are digested by means of enzymes contained in the feed. The
most important function of the rumen and omasum is the maceration of the
fibrous substances, and the digestion of the cellulose. Between sixty and
seventy per cent of the cellulose is digested in the rumen.

_The abomasum_ is lined by a gastric mucous membrane. The gastric juice
secreted converts the protein into peptones. In the young a milk curdling
ferment is also secreted by the glands of this compartment.

THE STOMACH OF THE HOG is a type between the carnivora and ruminant. The
digestive changes may be divided into four stages. The first period is one
of starch conversion; the second period is the same, only more pronounced;
the third period, both starch and protein conversion occurs; and the fourth
period is taken up mostly with protein digestion.

ACUTE INDIGESTION OF THE STOMACH OF SOLIPEDS.--Diseases of the stomach are
less common in solipeds than in ruminants. The simple stomach of the horse
and the comparatively unimportant place that it occupies in the digestion
of the feed renders it less subject to disease. Only under the most
unfavorable conditions for digestion of the feed does this class of
disorders occur. Acute indigestion in the form of overloading and
fermentation occurs in the stomach (Fig. 11).

_The predisposing causes_ that have to do with the development of these
disorders, are the small capacity of the stomach and the location and
smallness of the openings leading from the oesophagus and into the small
intestines. Greedy eaters are more prone to indigestion than animals that
eat slowly and are fed intelligently.

[Illustration: FIG. 11.--Dilated stomach of horse.]

_The following exciting causes_ may be mentioned: Sudden changes in ration;
feeding too much green feed or grain; feeding frozen or decomposed feeds;
drinking ice-cold water; and violent exercise or work that the animal is
not accustomed to, immediately after feeding are the common
disease-producing factors.

_The symptoms_ may vary from impaired appetite and slight restlessness to
violent, colicky pains. In the large majority of cases the attendant is
unable to differentiate between this and other forms of acute indigestion.
The characteristic symptoms are attempts at regurgitation and vomiting,
assuming a dog-sitting position and finally such nervous symptoms as
champing of the jaws, staggering movement and extreme dulness.

The violent form of gastric indigestion frequently ends in death. Rupture
of the stomach is not an uncommon complication (Fig. 12).

[Illustration: FIG. 12.--Rupture of stomach of horse.]

_The treatment_ is both preventive and medicinal. This digestive disorder
can be prevented. The feeding of the right kind of a ration and in the
right way, and avoiding conditions that may interfere with the digestion of
the feed, are the general lines of preventive treatment indicated. Such
measures are of special importance in the handling of animals that possess
an individual predisposition toward this class of disease. In mild attacks
the animal should be subjected to a rigid or careful diet during the attack
and for a few days later.

It is advisable to place the animal in a comfortable stall that is well
bedded with straw and plenty large for it to move about in. If a roomy
sick-stall can not be provided, a grass lot or barn floor may be used. If
the weather is chilly or cold, the body should be covered with a blanket
and roller bandages applied to the limbs.

Bulky drenches should not be given. Stimulants and drugs capable of
retarding fermentation are indicated. Sometimes the administration of a
sedative is indicated. Treatment should be prompt, as in many cases
fermentation of the contents of the stomach occurs and gases form rapidly.
From two to four ounces of oil of turpentine may be given in from six to
eight ounces of linseed oil.

ACUTE INDIGESTION OF THE STOMACH OF RUMINANTS.--The different forms of
acute indigestion are bloating, overloading of the rumen and impaction of
the omasum.

TYMPANITES, "BLOATING."--This disorder is usually caused by animals feeding
on green feeds, such as clover, alfalfa and green corn, that ferment
readily. Stormy, rainy weather seems to favor bloating. The consumption of
spoiled feeds such as potatoes and beets may cause it. The drinking of a
large quantity of water, especially if cold, chills the wall of the rumen
and interferes with its movement. Frozen feeds may act in the same way.
Sudden changes in the feed, inflammation of the rumen, and a weak
peristaltic movement of the paunch resulting from disease or insufficient
nourishment are frequent causes. It may occur in chronic disease. In
tuberculosis, bloating sometimes occurs.

_The symptoms_ are as follows: The paunch or rumen occupies the left side
of the abdominal cavity, hence the distention of the abdominal wall by the
collecting of gas in the rumen occurs principally on that side. The gas
forms quickly and the distended wall is highly elastic and resonant. The
animal stops eating and ruminating, the back may be arched and the ears
droop. In the more severe cases the wall of the abdomen is distended on
both sides, the respirations are quickened and labored, the pulse small and
quick, the eyes are prominent and the mucous membrane congested. Death
results from asphyxia brought on by the distended paunch pushing forward
and interfering with the movement of the lungs and the absorption of the
poisonous gases.

_The treatment_ is both preventive and medicinal. This form of acute
indigestion can be largely prevented by practising the following preventive
measures: All changes in the feed should be made gradually, especially if
the ration fed is heavy, or the new ration consists largely of green,
succulent feed. Cattle pasturing on clover should be kept under close
observation. It is not advisable to pasture cattle on rank growths of
clover that are wet with dew or a light rain. Bloating can be quickly
relieved by puncturing the wall of the paunch with the trocar and cannula.
The operation is quite simple and is not followed by bad results. The
instrument is plunged through the walls of the abdomen and rumen in the
most prominent portion of the flank, midway between the border of the last
rib and the point of the haunch (Fig. 13). The trocar is then withdrawn
from the cannula. After the gas has escaped through the cannula, the trocar
is replaced and the instrument withdrawn. After using the trocar and
cannula, the instrument should be cleaned by placing it in boiling hot
water. It is advisable to wash the skin at the seat of the operation with a
disinfectant before operating. In chronic tympanitis, it is sometimes
advisable to leave the cannula in position by tying a tape to the flange,
passing it around the body and tying.

As a cathartic for cattle, we may give one quart of linseed and from two to
four ounces of turpentine, or one to two pounds of Epsom or Glauber's
salts, dissolved in plenty of water. Sheep may be given about one-fourth
the dose recommended for cattle.

[Illustration: FIG. 13.--The X indicates the point where the wall of flank
and rumen are punctured with trocar and cannula in "bloat."]

OVERLOADING THE RUMEN.--This form of indigestion occurs when ruminants have
access to feeds that they are not accustomed to. As a result, they eat
greedily and the mass of feed in the rumen becomes so heavy that the walls
of the organ can not move it about, and digestion is interfered with. This
is especially true of succulent feeds. A diseased condition of the animal
predisposes it to this disorder. If after eating an excessive amount of
dry, innutritions fodder, the animal drinks freely of cold water, acute
symptoms of overloading are manifested.

_The general symptoms_ occurring in overloading resembles those seen in
bloating. The symptoms may be mild and extend over a period of several
days, or it may take on a highly acute form, terminating fatally within a
few hours. The acuteness of the attack depends on the character and
quantity of feed eaten. If a large quantity of green feed is eaten,
fermentation occurs and the animal may die within a few hours. The swelling
on the left side has a doughy feel. It is not as elastic and resonant as in
bloat, even when complicated by some gas formation. The animal may stop
ruminating, refuse to eat, and act dull. In the more severe cases the
respirations are hurried and labored, the pulse small and quick and the
expression of the face indicates pain. Colicky pains sometimes occur. Death
may occur from shock or asphyxia.

_The treatment_ is both preventive and curative. This disease can be
prevented by using the necessary precautions to prevent animals from
overeating. If gas forms, the trocar and cannula should be used. A drench
of from one to two pounds of Epsom or Glauber's salts should be given.
Sheep may be given from four to six ounces of Epsom or Glauber's salts. We
should endeavor to stimulate the movement of the paunch by pressure on the
flank with the hand, throwing cold water on the wall of the abdomen and by
hypodermic injections of strychnine. Rumenotomy should be performed when
necessary. This operation consists in opening the walls of the abdomen and
rumen, and removing a part of the contents of the rumen. This is not a
dangerous operation when properly performed, and should not be postponed
until the animal is too weak to make a recovery.

IMPACTION OF THE OMASUM.--This disease may occur as a complication of other
forms of acute indigestion and diseases accompanied by an abnormal body
temperature. Feeds that are dry and innutritions commonly cause it. Other
causes are an excessive quantity of feed, sudden changes in the diet and
drinking an insufficient quantity of water.

As in other diseases of the stomach, the appetite is diminished, rumination
ceases or occurs at irregular intervals, and the animal is more or less
feverish. Bloating and constipation may occur. The animal may lose flesh,
is weak, walks stiffly and grunts as though in pain when it moves about in
the stall and at each respiration. In the acute form, marked symptoms are
sometimes manifested. At first the animal acts drowsy; later violent
nervous symptoms may develop.

_The course_ of this disease varies from a few days to several weeks. Death
frequently occurs. Frequently a diarrhoea accompanies recovery, a portion
of the faeces appearing black with polished surfaces, as though they had
been baked.

_The preventive treatment_ consists in practising the necessary precautions
against the development of this disease by avoiding sudden changes in the
feed, the feeding of dry, innutritions feeds in too large amounts, allowing
animals plenty of water and providing them with salt. The best purgative to
give is Glauber's or Epsom salts in from one- to two-pound doses, dissolved
in at least one gallon of water. This physic may be repeated in from twelve
to eighteen hours if necessary. Two drachms of tincture of nux vomica and
one ounce of alcohol may be given in a drench three times daily. Hypodermic
injections of strychnine, eserine, or pilocarpine are useful in the
treatment of this disease. When recovery begins, the animal should be
allowed moderate exercise and be fed food of a laxative nature.

FOREIGN BODIES IN THE STOMACH OF RUMINANTS.--Foreign bodies such as hair
balls and wire are very commonly found in the reticulum. This is because of
the habits of this class of animals. Cattle eat their feed hastily and do
not pick it over as carefully as does the horse.

Smooth, round objects do no appreciable harm unless they block the opening
into the third compartment of the stomach. This frequently occurs in
wool-eating lambs. Sharp-pointed objects may penetrate the surrounding
tissues or such organs as the spleen, diaphragm, and pericardial sack. If
these organs are injured by the foreign body serious symptoms develop. The
_general symptoms_ are pain, fever, weakness and marked emaciation. It is
very difficult to form a correct diagnosis, as the disease comes on without
any apparent cause. Sometimes a swelling is noticed in the right and
inferior abdominal region. If the heart becomes injured, symptoms of
pericarditis are manifested.

_The treatment_ is largely preventive. Special care should be used to avoid
getting foreign substances into the feed given to cattle. The feed troughs
should be kept clean; we should avoid dropping nails and staples into the
feed when repairing the silo or grain bin; and pieces of baling wire should
be removed from straw or hay. Feeds known to be dirty should be run through
a fanning mill before feeding.

INFLAMMATION OF THE STOMACH OF SWINE.--Overloading and feeding spoiled feed
are _common causes_ of inflammation of the stomach. Swill-fed hogs are most
commonly affected with this disorder. Overloading more often results in an
inflammation of the stomach if the overloading follows the feeding of a
light ration, and the weather is extremely warm. Hogs that are accustomed
to eating salt may eat too much of it when fed to them after it is withheld
for a week or longer, and a large quantity of water is taken soon
afterwards. Slop containing alkaline washing powders and soaps irritate the
stomach and intestines and cause a serious inflammation.

_The symptoms_ are loss of appetite, restlessness and sometimes colicky
pains. The hog usually wanders off by itself, acts dull, grunts, lies down
in a quiet place or stands with the back arched and the abdomen held tense.
Vomiting commonly occurs. Sometimes the animal has a diarrhoea. The body
temperature may be above normal.

_The treatment_ consists in avoiding irritating feeds and sudden changes in
the kind or quantity of feed fed. Drenching with hot water, or with about
one ounce of ipecacuan may be practised. From one to three ounces of castor
oil, depending on the size of the hog, may be given. After recovery the
hogs should be confined in a comfortable pen and fed an easily digested
ration.

DISEASES OF THE INTESTINES

GENERAL DISCUSSION.--The intestinal tract of solipeds is the best developed
of any of the domestic animals (Fig. 14). It is divided into two portions,
_small_ and _large_. The _small intestine_ is a little over seventy feet in
length and about one and one-half inches in diameter. The mucous membrane
lining presents a large absorbing surface and is well supplied with
absorbing vessels that take up the sugars, proteids and fats, which are
finally distributed to the body cells by the blood capillaries. In addition
to these absorbing vessels the mucous membrane contains intestinal glands
that secrete the intestinal juice. Other digestive secretions from the
pancreatic gland and the liver are poured into the small intestine near its
origin. These digestive juices act on the proteids, sugars, starches and
fats, changing them into substances that are capable of being absorbed.

[Illustration: FIG. 14.--Photograph of model of digestive tract of horse:
oesophagus; stomach; liver; small intestine; large intestine; spleen.]

After disengaging itself from the mass of loops lodged in the region of the
left flank, the small intestine crosses to the region of the right flank,
where it terminates in the first division of the large intestine.

_The large intestine_ is formed by the following divisions: caecum, double
colon, floating colon and rectum. The caecum is a large blind pouch that
has a capacity of about seven gallons. The double colon is the largest
division of the intestines. It is about twelve feet in length and has a
capacity of about eighteen gallons. This portion of the intestine
terminates in the region of the left flank in the floating colon. The
latter is about ten feet in length and about twice the diameter of the
small intestine, from which it can readily be distinguished by its
sacculated walls. The rectum is the terminal portion of the intestinal
tract. It is about one and one-half feet in length and possesses heavy,
elastic walls.

Fermentation and cellulose digestion occur in the caecum and double colon.
It is in the floating colon that the faeces are moulded into balls. The
faeces are retained in the rectum until defecation takes place.

The _intestinal tract of cattle_ is longer than that of solipeds and the
different divisions are not as well defined as in the horse's intestine and
about one-half its diameter. The large intestine is about thirty-five feet
in length and its capacity six or seven gallons (Fig. 15).

ACUTE INTESTINAL INDIGESTION OF SOLIPEDS.--Acute indigestion is more common
in horses and mules than it is in any of the other domestic animals.
Because of the difference in the causes and symptoms manifested, we may
divide it into the following forms: spasmodic, flatulent and obstruction
colic.

_The predisposing causes_ are general and digestive debility resulting from
the feeding of an insufficient or unsuitable ration, and general and
parasitic diseases of the intestine. Nervous, well-bred horses are most
susceptible to nervous or spasmodic colic.

_The direct causes_ are improper methods of feeding and watering; giving
the animal severe or unusual exercise immediately before or after feeding;
the feeding of spoiled or green feeds and new grains; chilling of the body;
imperfect mastication of feed because of defective teeth; obstruction of
the intestine by worms.

The feeding of grain at a time when the animal is not in fit condition to
digest it results in imperfect digestion in both the stomach and intestine.
This leads to irritation of the intestine and abnormal fermentation of its
contents. The drinking of a large quantity of water immediately after
feeding grain flushes at least a part of the undigested grain from the
stomach through the small intestine and into the caecum. New grains, such
as new oats, are hurried along the small intestine and reach the large
intestine practically undigested. The two latter conditions are common
causes of _flatulent_ or _wind colic_. Sudden change in the ration,
especially to a green feed, may result in intestinal irritation and
flatulence.

[Illustration: FIG. 15.--Photograph of model of digestive tract of
ruminant: oesophagus; rumen; reticulum; omasum; abomasum; small intestine;
and large intestine.]

Horses that are greedy feeders and have sharp, uneven, smooth or diseased
teeth are unable to masticate the feed properly. This results in
unthriftiness caused by imperfect digestion and assimilation of the feed.
Such animals usually suffer from a catarrhal or chronic inflammation of the
intestine, and may have periodic attacks of acute indigestion or colic.

_Obstruction colic_ is very often caused by the feeding of too much
roughage in the form of straw, shredded fodder, or hay. Debility often
contributes to this form of indigestion, and the double colon may become
badly impacted with alimentary matter.

Worms may irritate the intestinal mucous membrane and interfere with
digestion, obstruct the intestine and cause debility and circulatory
disturbances. The large round worm may form a tangled mass and completely
fill a portion of the double colon.

[Illustration: FIG. 16.--A yearling colt that died of aneurism colic.]

Some species attach themselves to the intestinal wall, suck the blood of
the host and cause anaemia and debility. Colic resulting from _circulatory
disturbances_ is not common. The female of a certain species of
_strongulus_ deposits eggs in the mucous membrane. On hatching, the larvae
may enter a blood capillary, drift along in the blood stream and finally
come to rest in a large blood-vessel that supplies a certain portion of the
intestines with blood. Here the parasite develops. The wall of the vessel
becomes irritated and inflamed, pieces of fibrin flake off and drift along
the blood stream until finally a vessel too small for the floating particle
to pass through is reached and the vessel becomes plugged. The loop of
intestine supplied by it receives no blood. A temporary paralysis of the
loop occurs, which persists until a second vessel is able to take over the
function of the one that is plugged. This form of colic is most common in
old horses (Fig. 16).

Such complications of acute indigestion as _twisting, infolding_ and
_displacement of the intestine_ may occur. It is not uncommon for a
stallion to suffer from strangulated hernia, due to a rather large internal
inguinal ring and a loop of the intestine passing through it and into the
inguinal canal or scrotum. Such displacements are usually accompanied by
severe colicky pains.

_The symptoms_ vary in the different cases. In the mild form, the colicky
pains are not prominent, but in the acute form, the animal is restless,
getting up and down in the stall and rolling over. These movements are
especially marked when the abdominal pain is severe.

_In the spasmodic form_ the attack comes on suddenly, the colicky pains are
severe, and the peristaltic movement of the intestine is marked and
accompanied by loud intestinal sounds. In most cases of indigestion
characterized by fermentation and collections of gas in the intestine there
is gastric tympany as well.

Acute indigestion characterized by _impaction_ of the large intestine
pursues a longer course than the forms just mentioned, and the abdominal
pain is not severe.

_Congestion and inflammation_ of the intestine may result from the
irritation produced by the feed. When this occurs, the abdominal pain is
less violent. The animal usually acts dull, the walk is slow and unsteady,
and the respirations and pulse beats may be quickened.

A large percentage of the cases of acute indigestion terminate fatally. The
course of the disease varies from a few hours to several days.

_The treatment_ is both _preventive_ and _curative_. The preventive
treatment is by far the most important. This consists in observing right
methods of feeding and caring for horses. The attendant should note the
condition of the animal before feeding grain, feed regularly and avoid
sudden changes in feed. If a horse has received unusual exercise, it is
proper to feed hay first, and when the animal is cooled out, water and feed
grain. Drinking a small quantity of water when tired or following a meal is
not injurious, but a large quantity of water taken at such times is
injurious and dangerous to the health of the animal. The feeding of spoiled
or mouldy feeds to horses is highly injurious.

The horse should be given a roomy, comfortable stall that is well bedded,
or a clean grass lot. If the attack appears when the animal is in harness,
we should stop working it and remove the harness immediately. Work or
exercise usually aggravates the case and may cause congestion and
inflammation of important body organs. In cold weather the animal should be
protected by blankets. If the pain is violent, sedatives may be given. The
gaseous disturbances should be relieved by puncturing the wall of the
intestine with the trocar and cannula. Rectal injections of cold water may
be resorted to. Fluid extract of cannabis indica in quarter ounce doses and
repeated in one hour may be given in linseed oil. In all cases it is
advisable to drench the animal with one pint of raw linseed oil and two
ounces of turpentine. Strychnine, eserine and pilocarpine are the drugs
commonly used by the veterinarians in the treatment of acute indigestion.
Small and repeated doses of the above drugs are preferred to large doses.
This is one of the diseases that requires prompt and skilled attention.

Sharp, uneven or diseased teeth should receive the necessary attention. In
old horses, chopped hay or ground feeds should be fed when necessary.
Debility resulting from hard work, wrong methods of feeding and intestinal
disorders must be corrected before the periodic attacks of indigestion can
be relieved. If the presence of intestinal worms is suspected, the
necessary treatment for ridding the animal of these parasites should be
resorted to.

Bitter or saline tonics should be administered in the feed when necessary.
The following formula is useful as a digestive tonic: Sodium bicarbonate
and sodium sulfate, one pound of each, powdered gentian one-half pound, and
oil meal five pounds. A small handful of this mixture may be given with the
feed two or three times daily.

INFLAMMATION OF THE INTESTINES.--The same causes mentioned in inflammation
of the stomach and acute indigestion may cause this disease. It is most
frequent at times when there are great variations in the temperature.
Sudden cold or any influence that chills the surface of the body, or
internal cold caused by drinking ice water or eating frozen feed, may cause
it. The infectious forms of enteritis are caused by germs and ptomaines in
the feed. Drinking filthy water or eating spoiled, mouldy feeds are common
causes. In cattle pasturing in low, marshy places, enteritis may be common.
The toxic form is caused by irritating poisons, such as caustic acids,
alkalies and meat brine.

_In the mild form of enteritis_ the appetite is irregular, the animal acts
dull and stupid and may be noticed lying down more than common. Slight
abdominal pains occur, especially following a meal. An elevation in the
body temperature may be noted and the animal may drink more water than
usual. Constipation or a slight diarrhoea may be present. The feces may be
soft and foul smelling, coated with mucus, and slightly discolored with
blood.

_In the severe form of enteritis_ pressure on the abdomen may cause pain,
the respiration and pulse beats are quickened and the body temperature is
elevated. The abdominal pain may be severe and the animal is greatly
depressed or acts dull. The movement of the intestines is suppressed at
first and constipation occurs. Fermentation and the formation of gas may
take place. Later the intestinal peristalsis increases and a foul-smelling
diarrhoea sets in that is often mixed with blood. In the toxic form there
may be marked nervous symptoms. Spasms, convulsions, stupefaction and coma
may be manifested.

In the mild form recovery usually occurs within a few days. The more
serious forms of the disease do not terminate so favorably. In the toxic
form death usually occurs within a few days.

The large majority of cases of enteritis can be prevented by practising the
necessary _preventive measures_. It is very necessary that animals exposed
to cold be provided with dry sleeping quarters that are free from draughts.
Where a number of animals are fed a heavy grain ration, or fed from the
same trough, they should be kept under close observation. This is necessary
in order to detect cases of indigestion or overfeeding early, and resort to
the necessary lines of treatment, so as to prevent further irritation to
the intestinal tract. Live stock should not be forced to drink water that
is ice-cold. Low, poorly-drained land is not a safe pasture for cattle and
horses. Spoiled roots, grains and silage, mouldy, dirty roughage and
decomposed slops should not be fed to live stock.

_The treatment_ consists in withholding all feed and giving the animal
comfortable, quiet quarters--warm quarters and protection from the cold,
providing the animal with a heavy straw bed, or with blankets if necessary,
if the weather is cold. From five to forty grains of calomel may be given,
depending upon the size of the animal and the frequency of the dose, two or
three times a day. In case the animal is suffering severe pain, morphine
given hypodermically may be indicated. In the mild form and at the very
beginning of the attack, linseed oil may be administered to the larger
animals. The dose is about one quart. The smaller animals may be given
castor oil in from one- to four-ounce doses.

When convalescence is reached the animal should be fed very carefully, as
the digestive tract is not in condition to digest heavy rations or feeds
that ferment readily.

DIARRHOEA.--Diarrhoea occurs as a symptom of irritation and inflammation of
the intestinal mucous membrane. Sudden changes in the feed, the feeding of
a succulent green ration, severe exercise when the animal is not in
condition for it, and chronic indigestion may cause diarrhoea in the
absence of an intestinal inflammation.

_The following symptoms_ may be noted: Animals affected by a diarrhoea act
dull and weak; thirst is increased and the animal may show evidence of
fever; the intestinal evacuations are soft, thin, and sometimes have an
offensive odor. If the diarrhoea continues for several days, the animal
loses flesh rapidly and the appetite is irregular. In such cases weakness
is a prominent symptom.

Recovery usually occurs when the animal is dieted and rested.

_The treatment_ consists in giving a physic of linseed or castor oil.
Horses and cattle may be given from one-half to one quart of linseed oil;
sheep and hogs from one to four ounces of castor oil. Feed should be
withheld. Morphine may be given hypodermically to the large animals after a
period of six to eight hours following the administration of the physic.

The following formula is quite useful in checking diarrhoea: salol one-half
ounce, bismuth subnitrate one ounce, and bicarbonate of soda two ounces.
The dose of this mixture is from one to four drachms, depending on the size
of the animal, three or four times a day.

WHITE SCOURS OR DIARRHOEA IN YOUNG ANIMALS.--Young animals, when nursing
the mother or fed by hand, frequently develop congestion and inflammation
of the stomach and intestines. This disorder is characterized by a
diarrhoea.

_The causes_ may be grouped under two heads: wrong methods of feeding and
care, and specific infection.

The first milk of the mother is a natural laxative and aids in ridding the
intestine of the young of such waste material (meconium) as collects during
fetal life. If this milk is withheld, the intestine becomes irritated,
constipation occurs, followed by a diarrhoea or serious symptoms of a
nervous character, caused by the poisonous effect of the toxic substances
absorbed from the intestine on the nervous system.

Changes in the ration fed the mother, excitement, unusual exercise and
disease change the composition of the mother's milk. Such milk is
irritating to the stomach and intestines of the young. This irritation does
not always develop into a diarrhoea, but may result in a congestion of the
stomach.

When the young are raised artificially or by hand, and fed milk from
different mothers of the same or different species, or changed from whole
to skim milk, acute and chronic digestive disorders that are accompanied by
a diarrhoea are common. Feeding calves from filthy pails, allowing them to
drink too rapidly and giving them fermented milk are common causes of
scours.

White scours caused by irritating germs is a highly infectious disease. The
disease-producing germs gain entrance to the body by way of the digestive
tract and the umbilical cord.

Insanitary conditions, such as dark, cold, damp, filthy quarters, lower the
vitality of young animals, and predispose them to digestive disorders as
well as other diseases.

_The symptoms_ are as follows: Constipation accompanied by a feverish
condition precedes the diarrhoea; colicky pains are sometimes manifested;
the diarrhoea is usually accompanied by depression, falling off in appetite
and weakness. At first the intestinal discharges are not very foul
smelling; later the odor is very disagreeable. The faeces may be made up
largely of undigested, decomposed milk that adheres to the tail and hind
parts. If the diarrhoea is severe, the animal refuses to suckle or drink
from the pail, and loses flesh rapidly. It is usually found lying down. The
ears droop and the depression is marked. The body temperature may vary from
several degrees above to below the average normal.

_The infectious form_ of white scours may be diagnosed by the history of
the outbreak. In this form of the disease, a large percentage of the young
are affected and the death-rate is very high.

Calves and lambs frequently die of an acute congestion of the fourth
stomach. In this disease, the symptoms appear shortly after feeding. It is
characterized by colicky pains, convulsions and coma.

_The treatment_ is largely preventive. Young animals should be provided
with dry, clean, well-ventilated quarters and allowed plenty of exercise.
Colts thrive best if allowed to run in a blue grass pasture with the
mother. If the mother is worked, suitable provisions in the way of quarters
and frequent nursing should be provided. Calves, lambs and pigs are the
most frequent sufferers from insanitary quarters. In breeding, we should
always strive to get strong, vigorous, healthy young. The care given the
mother in the way of exercise and feeding is an important factor here.

The first milk of the mother should not be withheld from the young,
especially if the animal is raised by hand. We must also feed it regularly
and not too much at any one time. Any change in the milk should be made
gradually, and it is usually advisable to reduce the ration slightly when
such a change is made, so as not to overwork the digestive organs. Pails
and bottles from which the animal feeds should be kept clean.

Colts raised on cow's milk must be fed and cared for carefully. The milk
must be sweet and made more digestible by diluting it with one-third water.
A little sugar may be added. It is very advisable to add from one-half to
one ounce of lime water to each pint of milk fed. Frequent feeding is very
necessary at first, and we must not underestimate the quantity of milk
necessary to keep the colt in good condition. It should be taught to eat
grain as soon as possible.

Because of the irritated condition of the stomach and intestine, the animal
suffering from diarrhoea is unable to digest its feed. For this reason it
is very important to withhold all feed for at least twelve hours. Water
should be provided. The alimentary tract is relieved of the irritating
material by giving the animal a physic of castor or linseed oil. The dose
varies from one-quarter to one-half ounce for the lamb and from one to four
ounces for the colt or calf. It is advisable in most cases to follow this
with the following mixture: bicarbonate of soda one ounce, bismuth
subnitrate one-half ounce, and salol one-quarter ounce. The dose for the
colt and calf is one teaspoonful three times a day. Lambs and pigs may be
given from one-fourth to one-half the above dose.

It is usually advisable to give ewes and sows a physic if their young
develop a diarrhoea. Mothers that are heavy milkers may be given a physic
the second or third day following birth. The ration should be reduced as
well during the first week.

DISEASES OF THE DIGESTIVE TRACT OF POULTRY

GENERAL DISCUSSION.--The digestive tract of poultry is composed of the
following organs: mouth, gullet, crop, stomach, gizzard and intestines,
with the two large glands, the liver and pancreas. The digestion of the
feed begins in the crop. Here the feed is held for a short time, mixed with
certain fluids and softened. On reaching the stomach it becomes mixed with
the digestive fluid secreted by the gastric glands. This second digestive
action consists in thoroughly soaking the feed in the gastric juice, making
it soft and preparing it for maceration by the heavily muscled gizzard.
Following maceration it passes into the intestine. It is here that the
digestive action is completed and absorption occurs.

Under the conditions of domestication, poultry are subject to a great
variety of intestinal disorders.

DISEASES OF THE CROP.--Impaction and inflammation are the two common
diseases of the crop. _Large, impacted crops_ are usually caused by the
feeding of too much dry feed, fermentation of the contents of the crop and
foreign bodies that obstruct the opening from the organ.

_Inflammation of the crop_ is caused by excessive use of condiments in the
feed, putrid or spoiled feeds and eating caustic drugs, such as lime and
rat poison.

_The symptoms_ are dulness, an indisposition to move about, drooping wings
and efforts to eject gases and liquids. The crop is found greatly distended
and either hard or soft, depending on the quantity of feed present and the
cause of the distention. If fermentation is present the crop usually feels
soft.

_The preventive treatment_ consists in practising proper methods of
feeding. The _curative treatment_ of a recent case consists in manipulating
the mass of feed, breaking it up and forcing it upwards toward the mouth.
If difficulty in breaking up the mass is experienced, it is advisable to
administer a tablespoonful of castor oil to the bird.

If the above manipulations are unsuccessful, an operation is necessary.
This consists in making an opening through the skin and the wall of the
crop and removing the contents with tweezers. The opening must be closed
with sutures. The proper aseptic precautions must be observed.

In inflammation of the crop, the bird should be dieted for at least one
day, and one teaspoonful of castor oil given as a laxative.

ACUTE AND CHRONIC INDIGESTION.--The recognition of special forms of
indigestion in poultry is difficult. A flock of poultry that is subject to
careless and indifferent care may not thrive and a number of the birds
develop digestive disorders. This may be indicated by an abnormal or
depraved appetite and emaciated condition. Constipation or diarrhoea may
occur. In the more severe cases the bird acts dull, the feathers are
ruffled and it moves about very little.

_The treatment_ consists in removing the cause, and giving the flock a
tonic mixture in the feed. The following mixture may be used: powdered
gentian and powdered ginger, eight ounces of each, Glauber's salts four
ounces, and sulfate of iron two ounces. One ounce of the above mixture may
be given in ten pounds of feed.

WHITE DIARRHOEA OF YOUNG CHICKENS.--White diarrhoea is of the greatest
economic importance to the poultryman. The loss of chicks from this disease
is greater than the combined loss resulting from all other diseases. It is
stated by some authors that not less than fifty per cent of the chickens
hatched die from white diarrhoea.

Such a heavy death-rate as is attributed to this disease can not result
from improper methods of handling and insanitary conditions. Before it was
proven that white diarrhoea was caused by specific germs, a great deal of
emphasis was placed on such causes as debilitated breeding stock, improper
incubation, poorly ventilated, overcrowded brooders, too high or too low
temperatures and filth. Such conditions are important predisposing factors,
and may, in isolated cases, result in serious intestinal disorders.

_The microorganisms causing_ this disease belong to both the plant and
animal kingdoms. Infection usually occurs within a day or two following
hatching. Chicks two or three weeks of age seldom develop the acute form of
the disease. Incubator chicks are the most susceptible to the disorder.

_The following symptoms occur_: The chicks present a droopy, sleepy
appearance; the eyes are closed, and the chicks huddle together and peep
much of the time; the whitish intestinal discharge is noticed adhering to
the fluff near the margins of the vent, and the young bird is very weak;
death may occur within the first few days. After the first two weeks the
disease becomes less acute. In the highly acute form the chicks die without
showing the usual train of symptoms.

It is very easy to differentiate between the infectious and the
non-infectious diarrhoea. In the latter, the percentage of chicks affected
is small and the disease responds to treatment more readily than does the
infectious form. The death-rate in the latter form is about eighty per
cent.

_The treatment_ of diarrhoea in chicks from any cause is preventive. This
consists in removing the cause. No person can successfully handle poultry
if he does not give the necessary attention to sanitation. Poultry houses,
runs, watering fountains and feeding places must be constantly cleaned and
disinfected. The degree of attention necessary depends on the surroundings,
the crowded condition of the poultry houses and runs, and the presence of
disease in the flock. If disease is present, we can not clean and disinfect
the quarters too often. The attendant can not overlook details in handling
the incubator or brooder and feeding the chicks and be uniformly
successful.

If the disease is known to be present in the flock, the incubators and
brooders should be thoroughly disinfected by fumigating them with
formaldehyde gas. If dirty, they should first be washed with a water
solution of a good disinfectant. For a period of from twenty-four to
forty-eight hours after hatching, the chicks should receive no feed. Dr.
Kaupp recommends as an intestinal antiseptic, sulfocarbolate thirty grains,
bichloride of mercury six grains, and citric acid three grains, dissolved
in one gallon of water. This solution should be kept in front of the chicks
all the time. A water solution of powdered copper sulfate (about one-half
teaspoonful dissolved in one gallon of water) may be used.


QUESTIONS

 1. Name the organs that form the digestive apparatus.

 2. What digestive action on the feed occurs in the mouth?

 3. Describe the causes and symptoms of inflammation of the mouth; describe
    the treatment.

 4. Give the causes for depraved appetite; describe the symptoms and
    treatment.

 5. Give the capacity of the horse's stomach.

 6. Name the different compartments of the ruminant's stomach.

 7. Give the capacity of the stomach of ruminants.

 8. Name the different stages of digestion occurring in the stomach of the
    hog.

 9. What forms of acute indigestion involve the stomach of solipeds? Give
    causes and treatment.

10. Give the causes of indigestion of the stomach of ruminants.

11. Give the treatment for the different forms of indigestion of the
    stomach of ruminants.

12. Name the divisions of small and large intestines of solipeds and
    ruminants.

13. What is the capacity and length of large intestine of solipeds and
    ruminants?

14. What are the different forms of acute indigestion of the horses, and
    causes?

15. Give a general line of treatment for acute indigestion of the horse.

16. Give the causes of white diarrhoea in the young chicks; give a line of
    treatment.

17. Name the organs of the digestive apparatus of poultry.

18. Name the common diseases of the digestive apparatus of poultry, and
    give the causes.



CHAPTER V

DISEASES OF THE LIVER


GENERAL DISCUSSION.--The liver is one of the most important glands of the
body, as well as the largest. Because of its physiological influence over
the functions of the kidneys, intestines, and body in general and the
varied functions that it possesses, it is frequently affected by functional
disorders.

All of the blood that comes directly from the intestine is received by the
liver. It secretes the bile, neutralizes many of the poisonous substances
and end products of digestion that are taken up by the absorbing vessels of
the intestine, and acts as a storehouse for the glycogen.

It can be readily understood from this brief statement of the nature of the
liver functions, that any functional disorder of the liver may be far
reaching in its effect. In many of the diseases that involve other organs,
the liver may be primarily affected. It is difficult to diagnose functional
disorders of the liver that are responsible for a diseased condition of
some other body organ. A knowledge of the physiology and pathology of the
liver is of the greatest importance in the diagnosis of this class of
disorders.

In the larger domestic animals, symptoms of liver diseases are more obscure
than in the small animals. In certain parasitic diseases and in mixed and
specific infectious diseases, the liver may show marked pathological
changes.

COMMON CAUSES OF LIVER DISORDERS.--Domestic animals commonly live under
very unnatural conditions. Ill results do not follow unless these
conditions are so extreme as to violate practically all of the health laws.
Pampered animals are especially prone to liver disorders. The feeding of
too heavy and too concentrated a ration together with insufficient exercise
is one of the most common causes of disorders of the liver. The feeding of
a ration that is unsuitable for that particular species is a common source
of disease in animals. For example, the feeding to carnivora of a ration
made up largely of starchy feed, and the feeding of a ration containing an
excessive quantity of protein to herbivorous animals may result in
intestinal, liver and nervous disorders. Spoiled feed may prove highly
injurious. Catarrhal inflammation of the intestine and intestinal parasites
may obstruct the bile duct, and interfere seriously with the functions of
the liver.

_Symptoms_.--In diseases of the liver the appetite is irregular or the
animal refuses to eat, is constipated, or has diarrhoea. The faeces may be
grayish colored or foul smelling. Colicky pains are sometimes manifested.
Usually the animal acts dull and weak. A raise in body temperature may be
noted. The visible mucous membranes may appear yellowish- or brownish-red in
color.

_Treatment_.--Animals grazing over well drained pastures that are free from
injurious weeds and provided with plenty of drinking water, seldom develop
diseases of the liver. Exercise, a natural diet and plenty of clean water,
as well as preventing liver disorders, may be classed among the most
important of all curative agents. Laxatives or cathartics, such as oils,
salts, aloes, and calomel, in small doses may be given. We prefer the
administration of oil or aloes to horses, Glauber's or Epsom salts to
ruminants, and calomel to dogs. The administration of minimum doses of
these drugs, and repeating the dose after a short interval, is preferable
to large doses. Alkaline tonics are also indicated. The following mixture
may be given: bicarbonate of soda, sulfate of soda and common salt, eight
ounces of each, and powdered gentian and sulfate of iron, four ounces of
each. Large animals may be given a small tablespoonful of this mixture with
the feed three times a day. The dose for sheep and hogs is one teaspoonful.
A very light, easily digested ration should be fed.


QUESTIONS

1. What can be said of the importance of the liver?

2. Tell something of its duties as a gland.

3. In what animals are liver troubles most conspicuous when present?

4. Give causes of liver disorders.

5. What are the symptoms?

6. What are the most important natural cures?

7. What rule may be given for adapting suitable laxatives to different
   classes of animals?



CHAPTER VI

DISEASES OF THE URINARY ORGANS


GENERAL DISCUSSION.--The urinary apparatus is composed of two glands, the
kidneys and an excretory apparatus that carries the excretion of the
kidneys to the outside.

The kidneys are situated in the superior region of the abdominal cavity
(sublumbar) above the peritoneum, and to the right and left of the median
line. They are highly vascular glands, somewhat bean-shaped and of a deep
red color. These glands are capable of removing from the blood a fluid that
is essentially different in composition and which, if retained in the
blood, would be harmful or poisonous to the body tissues.

The kidney excretions are carried from the pelvis of the kidneys by the
right and left ureters. These canals terminate in the bladder, an
oval-shaped reservoir for the urine. This organ is situated in the
posterior portion of the abdominal cavity and at the entrance to the pelvic
cavity. Posteriorly, it forms a constricted portion or neck. It is here
that the urethra originates. This canal represents the last division of the
excretory apparatus. In the female, the urethra is short and terminates in
the vulva. In the male it is long and is supported by the penis.

The urine secreted by the kidneys is a body excretion, and consists of
water, organic matter and salts. The nitrogenous end-products, aromatic
compounds, coloring matter, and mucin form the organic matter. The
nitrogenous end-products and aromatic compounds are urea, uric and hippuric
acids, benzoic acid and ethereal sulfates of phenol and cresol. The salts
are sulfates, phosphates and chlorides of sodium, potassium, calcium and
magnesium. The organic and inorganic matter varies with the ration.

The quantity of urine secreted within a given time varies in the different
species and at different times in the same individual. In the horse the
quantity secreted in twenty-four hours varies from twelve to fifteen pints;
in cattle from ten to forty pints; in sheep from one-half to one and
three-quarter pints. The normal color of the urine varies. In the horse it
is yellow or yellowish-red; in cattle and sheep yellowish; and in the dog a
straw yellow. The specific gravity varies with the quantity secreted and
the ration fed. When the quantity of urine secreted is above the average,
the specific gravity is usually low.

THE NECESSITY OF EXAMINING THE URINE.--In diseases of the urinary
apparatus, a careful examination of the urine is very necessary in order to
be able to form a correct diagnosis. In domestic animals it is impractical
to attempt to determine the exact amount of urine passed within a certain
time, but we can make a general estimate of the quantity passed by
carefully observing the animal and noting the condition of the bedding in
the stall. The sample of urine to be examined is best taken from urine
collected at different periods during the day. We should note its color and
consistency. The different substances in the urine can be determined only
by determining the specific gravity, testing with certain chemical reagents
and by making a microscopic examination of the sediment. Normal urine from
the horse may be turbid or cloudy and more or less slimy, because of the
presence of mucin. This is less true of other species. In disease the color
of the urine may be changed to a pale yellow, red or brown. For example, in
congestion of the kidneys the urine is light in color and rather
transparent; in southern cattle fever it may be red; and in azoturia it may
be brown.

EXCESSIVE URINATION.--The horse is the most common sufferer from excessive
secretion of urine. The most common _causes_ are musty feeds, such as hay,
grain and shipped feeds. New oats, succulent feeds and acrid plants may
sometimes cause it. In the fall of the year, when the season is changing
from warm to cool weather and the horse eliminates less water from the body
by way of the skin, the kidneys may become more active and the quantity of
urine secreted be greatly increased. This, however, is a normal
physiological condition and should not be confused with this disease.

The first _symptom_ noted is the frequent passing of a large quantity of
urine. The animal drinks more water than usual and the appetite is poor.
Dulness and a weak, emaciated condition are prominent symptoms. Death
occurs unless the cause of the disease is removed. If the poisonous
substance has been acting for some time, it is difficult to cure the
animal.

This disease can be _prevented_ by eliminating spoiled feeds from the
ration fed to animals in our care. Early in the attack the necessary
attention to the ration and the feeding of a clean, nourishing ration is
sufficient to correct the disease. The quantity of water drunk by the
animal should be limited. Complete rest is indicated. Laxatives, stimulants
and tonics should be given if necessary.

NEPHRITIS.--Congestion and inflammation of the kidneys commonly occur in
mixed and specific infectious diseases, such as septicaemia, pyaemia and
influenza. The toxic effect of spoiled feeds, impure drinking water, and
irritating drugs like cantharides and turpentine may so irritate the
kidneys as to cause them to become inflamed. Chilling of the skin and
nervousness or extreme fear may sometimes cause a congestion of these
organs. Inflammation of the kidneys is a common complication of azoturia.
Irritation from parasites should be included among the causes of this
disease.

The _symptoms_ vary in the different stages of the disease. During the
period of active congestion the quantity of urine secreted is increased.
The scant secretion of urine, dark in color and thick or turbid, is
suggestive of an inflammation of the kidneys. The animal moves stiffly, the
back may be arched, urination is painful and the urine is passed in very
small amounts. The appetite is irregular or suppressed, the pulse strong at
first but later small and weak, and the body temperature is elevated. On
making a rectal examination we find the bladder empty and the kidneys
enlarged and sensitive.

When the kidneys become so badly diseased that they can no longer perform
their function of separating from the blood the nitrogenous end-products of
digestion, uraemic poisoning occurs. In this later stage of the disease the
animal staggers about if moved, and finally goes down in the stall and is
unable to get up. Death is usually preceded by convulsions and coma.

_The prognosis_ is very unfavorable, death occurring in the majority of
cases. In azoturia of horses and in infectious diseases, the inflammation
is nearly always acute. The color of the urine, its high specific gravity
and the small quantity passed are valuable symptoms to consider in the
recognition of this disease. Chronic inflammation generally develops slowly
and may not give rise to any very prominent symptoms at first.

_The preventive treatment_ of nephritis consists in careful nursing of
animals affected with acute infectious diseases, a clean water supply and
avoiding the feeding of spoiled feeds. The _curative treatment_ is largely
careful nursing. The animal should be given comfortable, well-ventilated
quarters and complete rest. Chilling of the skin should be especially
guarded against by protecting the body with heavy blankets and applying
roller bandages to the limbs when necessary. The diet must be of such a
nature as not to increase the work of the kidneys. For the first few days
the animal should receive very little feed or water. Later a sloppy diet of
sweet milk, green feed and mashes should be fed. Such purgatives as aloes
and Glauber's salts are indicated at a very early stage in the disease. We
must encourage the elimination of waste products by way of the skin in the
larger animals by vigorous rubbing, blanketing and the administration of
such drugs as pilocarpine. If the animal becomes weak, general and heart
tonics may be given.

CYSTITIS.--Inflammation of the bladder is not an uncommon disease of
horses. It is commonly _caused_ by retention of the urine, calculi in the
bladder and chilling of the body. Irritating drugs that are eliminated from
the body in the urine, and infection of the bladder by germs may cause it.

_The symptoms_ are usually marked. The inflammation is characterized by
more or less pain, depending on the degree of the inflammation, and
frequent passing of urine. Only a small amount of urine is passed at each
attempt, and in severe inflammation it may contain pus or blood. Colicky
pains sometimes occur. The pain is usually manifested by a stiff,
straddling gait and tenderness when pressure on the bladder is made by
introducing the hand into the rectum or vagina, and pressing over the
region of the bladder. General symptoms, such as elevation in body
temperature and irregular appetite, may be manifested.

_The treatment_ should be first directed at removing the cause. If a cystic
calculus is present in the bladder it should be removed. If the retention
of the urine is caused by some local condition, and this is very often the
case in nervous, well-bred animals, this must first be corrected. It is
best to feed green and soft feeds, such as bran mash and chopped hay, and,
if the animal will take them, gruels. A physic of castor or linseed oil
should be given occasionally. It is very necessary that the animal be kept
quiet. Comfortable, clean quarters and a good bed should be provided.
Whenever necessary the animal should be blanketed. The medicinal treatment
consists in irrigating the bladder with antiseptic solutions, and
administering drugs that when eliminated by way of the urine may change its
composition and render it less irritating. The following mixture may be
given: potassium chlorate two ounces, salol one-half ounce, and powdered
nux vomica one ounce. This mixture may be divided into sixteen powders. One
of the powders should be given with each feed.

RETENTION OF THE URINE.--This may be due to a variety of _causes_. In the
ox and ram, small calculi collect in the S-shaped curvature of the urethra,
or at its terminal extremity. In the horse, cystic calculi are more common
than urethral. In cattle and hogs, fatty secretions from the inflamed
lining membrane of the sheath of the male may accumulate, and obstruct the
flow of urine from the anterior opening. The giving of feed rich in salts,
concentrated urine resulting from feeding of too dry a ration, insufficient
exercise and inflammation of the bladder are the direct causes of calculi.

Compression of the urethra by growths or tumors, strictures of the urethra,
distended bladder, spasm of the neck of the bladder in nervous animals,
paralysis of the bladder and injuries to the penis are common causes of
retention of the urine.

_The early symptoms in ruminants_ are not usually recognized until a day or
two after retention of the urine has occurred. The symptoms are then quite
marked. The animal acts dull, refuses to eat, rumination is stopped, and
there is a constant effort to urinate, as indicated by the raising of the
tail and rhythmical contractions of the urinary muscles just below the
anus. Urine may dribble from the sheath or the flow may be completely
suppressed. The odor of urine may be marked.

_Horses show symptoms_ of abdominal pain. The animal may move about the
stall, lie down and get up again, or make unsuccessful attempts to urinate.
On examination the bladder is found to be greatly distended with urine. In
the horse the retention is recognized at an earlier period than in
ruminants, because of the prompt, decided symptom of pain.

Retention of the urine commonly terminates in rupture of the bladder in
ruminants. When this occurs, the symptoms of pain are less evident. Death
occurs from uraemic poisoning and peritonitis. The outcome is less
favorable in ruminants than in solipeds.

_Inflammation of the sheath_ can be readily recognized because of the local
swelling.

_The following lines of treatment_ are recommended: A ration or feed that
favors the formation of calculi should not be fed to animals; inflammation
of the sheath should receive prompt treatment--this consists in irrigating
the part with warm, soapy or alkaline water, followed by an antiseptic
wash; we may attempt to work the urethral calculi forward and out of the
S-curve in the urethra; if this is unsuccessful, urethrotomy for their
removal may be attempted.

The retention of the urine in horses, because of spasm or paralysis of
certain muscles, may be treated by passing the catheter. Sometimes
spreading litter under the horse and keeping it quiet may induce it to
urinate. Hot packs over the region of the back may be used. The treatment
for calculi is entirely surgical. The operation for the removal of cystic
calculi in the horse, although difficult, is followed by good results.


QUESTIONS

1. Describe the urinary apparatus.

2. Give the composition of the urine and quantity secreted in the different
   animals.

3. State method of determining quantity and composition of urine secreted
   by different domestic animals.

4. Give the causes and treatment of excessive urination.

5. Give the causes and treatment of congestion and inflammation of the
   kidneys.

6. Give the causes of cystitis; symptoms; treatment.

7. Give the causes and treatment of retention of the urine.



CHAPTER VII

DISEASES OF THE GENERATIVE ORGANS


GENERAL DISCUSSION.--The study of the organs concerned with the
reproduction of the species is essential in order to acquire a knowledge of
their several functions. It is only through an understanding of these
functions that we can prepare ourselves to correctly recognize, and
successfully treat, or prevent, such diseases as may involve the organs of
generation. A knowledge of the structure and function of the generative
organs of the female is of greater importance from the standpoint of
disease, than is a similar knowledge of the generative organs of the male.
The female is concerned with the complete reproductive process, which may
be divided into four stages. These are _copulation_, _fecundation_,
_gestation_ and _parturition_. The male is concerned only with _copulation_
and _fertilization_ of the ovum by the spermatozoa, while the female must
protect and nourish the embryo and foetus until it has become sufficiently
developed to live independently of the protection and nourishment afforded
it within the womb. When the final stage of gestation is reached, birth or
the act of parturition occurs.

GENITAL ORGANS OF THE FEMALE.--The female generative organs are the
ovaries, fallopian tubules, uterus, vagina, vulva and mammary glands.

_The ovaries_ are analogous to the testicles of the male. Their function is
to secrete ova. This pair of glands is suspended from the superior region
(sublumbar) of the abdominal cavity by folds of the lining membrane.
Leading from the ovaries, but connected with the surface of these glands
only during the period of oestrum or heat, are the fallopian tubules. Their
function is to carry the ovum from the ovaries to the uterus.

_The uterus or womb_ is a membranous sack situated in the sublumbar region
and at the inlet to the pelvic cavity. It is held in position by numerous
folds of the lining membrane of the abdominal cavity. We may divide the
womb into three divisions, cornua, body and cervix.

The cornua or horns are long and cylindrical in shape. This portion of the
womb is greatly developed in animals, like the sow and bitch, that give
birth to several young. In the impregnated animal the wall of the cornua
that contains one or several foetuses, and the body as well, becomes
greatly thickened and the lining membrane more vascular.

The body is short in all domestic animals and connects the horns with the
cervix or neck. The latter is represented by a narrow portion that projects
backward into the vagina. In the cow the cervix is less prominent than in
the mare and the tissue that forms it, quite firm. In the cow the opening
in the cervix, the os, is very small.

_The vagina_ is a musculo-membranous canal that leads from the womb. In the
mare and cow it is about one foot in length. Its function is to take part
in copulation and parturition.

_The vulva_ is the external opening of the maternal passages. It shows a
vertical slit enclosed by lips, and interiorly it forms a passage that is
continuous with the vagina. This passage is about six inches long in the
larger animals. The different features that should be noted are the
clitoris, a small erectile organ located at the inferior portion of the
opening, the meatus urinaris, the external opening of the urethra, situated
in a depression in the floor of the vulva, and the hymen, an incomplete
membranous partition that may be found separating the vulva from the
vagina.

_The mammary glands or udders_ secrete the milk that nourishes the young.
The glands vary in number. The mare has two, the cow four (Fig. 17), the
ewe two and animals that give birth to several young, eight or more. Each
gland is surmounted by a teat or nipple. The glandular tissue consists of
caecal vesicles that form grape-like clusters around the milk tubules. The
milk tubules from the different portions of the gland converge and form
larger tubules that finally empty into small sinuses or reservoirs at the
base of the teat. Leading from these sinuses are one or several milk ducts
that open at the summit of the teat.

GENITAL ORGANS OF THE MALE.--The genital organs of the male are the
testicles, the ducts or canals leading from the testicles, the seminal
vesicles, the glands lying along the urethra, and the penis.

[Illustration: FIG. 17.--Photograph of model of udder of cow: milk duct;
milk sinuses; and glandular tissue.]

_The testicles_ are the glandular organs that secrete the spermatozoa, the
essential elements of the seminal fluid. These glands are lodged in the
scrotal sack, situated between the two thighs.

Lying along the superior border of the testicle is a mass of ducts, the
_epididymis_. The _vas deferens_ is the canal or duct that passes
from the epididymis to the region of the bladder and terminates near its
neck by emptying into the seminal vesicles.

_The seminal vesicles_ are two membranous pouches situated just above the
bladder. They act as receptacles for the seminal fluid. Two short ducts,
the _ejaculatory_, carry the seminal fluid from the seminal vesicles to the
urethra.

_The prostate gland_ is situated near the origin of the urethra. _Cowper's
glands_ lie along the course of the urethra and near the origin of the
penis. These glands empty their secretions into the urethra and dilute the
seminal fluid.

_The penis_ is the male organ of copulation. It originates at the arch of
the ischium and extends forward between the thighs. It may be divided into
fixed and free portions. The free portion is lodged in the prepuce or
sheath, but at the time of erection protrudes from it.

STERILITY, IMPOTENCY.--Fecundation does not always follow intercourse of
the male and female. Impotency in the male and sterility in the female
frequently occur.

_The causes_ are quite varied. A normal copulation may be impossible
because of injuries to, and deformities of, the parts and tumor growths.
Deformed genital organs and obstructions of the os by growths and scar
tissue are causes of sterility in the female.

Failure to breed is commonly caused by faulty methods of feeding and care.
Over-feeding and insufficient exercise may result in the body tissues
becoming loaded with fat. This may cause a temporary sterility, but if
persisted in, as is frequently the case in show animals, the sterility
becomes permanent because of the genital glands failing to secrete ova and
spermatozoa, or the lack of vitality of the male and female elements. Old
age and debility from disease or poor care may induce loss of sexual desire
and an absence of, or weakened spermatozoa in, the seminal fluid. The
refusal of the male to serve certain females is sometimes noted.

Tuberculosis may affect the ovaries and cause permanent sterility. In
inflammation of the lining membrane of the womb and vagina, the secretions
are abnormal and may collect in the womb and the passages leading to it.
These secretions destroy the vitality of the spermatozoa, and this
condition may be considered a common cause of sterility in the larger
animals. Many vigorous young males are made impotent by excessive
copulation. The excessive use of the male at any time may result in failure
to impregnate a large percentage of the females that he serves.

Barren females do not become pregnant after frequent intercourse with the
male. Young sterile females may not come in heat. Sometimes unnatural
periods of heat are manifested, the animal coming in heat frequently or
remaining in heat for a longer period than usual. This sometimes occurs in
tuberculosis of the ovaries. In chronic inflammation of the maternal
passage there is more or less discharge from the vulva. Both sexes may be
overly fat or weakened and debilitated by disease. Deformity of the
generative organs and growths may be found on making an examination.
Absence of, or lack of vitality of the spermatozoa may be determined by
microscopic examination of the seminal fluid.

_The treatment_ is largely preventive. It is very important that breeding
animals be kept in proper physical condition by avoiding the feeding of too
heavy or too light a ration, and allowing them sufficient exercise. The
male is more often affected by the latter cause than the female. This is
because the average stockman does not consider exercise given under the
right conditions an important factor in maintaining the vigor of the male.
Young males should not be given excessive intercourse with the female. Such
practice is certain to seriously affect the potency of the animal. The
excessive use of the stallion can be avoided by practising artificial
impregnation of a part of the mares that he is called to serve. Sterility
caused by growths and closure of the os may be corrected by an operation.

Chronic inflammation of the maternal passages should be treated by
irrigating the parts with a one per cent warm water solution of lysol, or
liquor cresolis compound. The parts should be irrigated daily for as long a
period as necessary. Fat animals should be subjected to a rigid diet and
given plenty of exercise. Following this treatment a stimulating ration may
be fed for the purpose of encouraging the sexual desire. In weak and
debilitated animals, the cause should first be removed and a proper ration
fed. Cantharides and strychnine are the drugs most highly recommended for
increasing the sexual desire.

SIGNS OF PREGNANCY.--The signs which characterize pregnancy are numerous
and varied. For convenience we may classify the many signs of pregnancy
under two heads, probable and positive. Under the head of probable signs,
we may group the following symptoms of pregnancy: cessation of heat;
changes in the animal's disposition; increase in the volume of the abdomen
and tendency to put on fat. The positive signs are the change in the volume
of the udder; the secretion of milk; the movement of the foetus and
presence of the foetus in the womb, as determined by rectal examination or
by the feel of the abdomen.

_The probable signs_ are not reliable, and should be considered only in
connection with some positive sign. Persons who base their opinion of the
condition of an animal that is supposed to be pregnant on probable signs,
are frequently mistaken. It has frequently happened that animals whose
condition was not at all certain have given birth to young, without giving
rise to what may be termed characteristic probable signs.

The earliest probable symptom is the cessation of heat. In the large
pregnant animals, irregular heat periods may occur, but in the majority of
cases we may safely consider the animal impregnated if several heat periods
are passed over.

It has been generally observed that the disposition of the pregnant animal
is changed. They become more quiet and less nervous and irritable. The
tendency of pregnant animals to put on fat is frequently taken advantage of
by the stockman, who may allow the boar to run with the herd during the
latter period of fattening.

The increase in the volume of the abdomen may be considered a _positive_
sign of pregnancy in the small animals, but in the mare and cow it can not
be depended on. Animals that are pregnant for the first time, do not show
as great an increase in the volume of the abdomen as do animals that have
gone through successive pregnant periods. The volume of the abdomen may
vary greatly in the different individuals, and can not be depended on as a
positive indication of pregnancy during the first two-thirds of the period
of pregnancy in the larger domestic animals.

Comparatively early in pregnancy, the presence of a foetus can be
determined by feeling the uterus through the wall of the rectum. In the
small domestic animals the feeling of the abdomen gives the best results.
In the cow this method of diagnosis is practised during the latter periods
of pregnancy. The examiner stands with his back toward the animal's head,
and on the right side of the cow and the left side of the mare. The palm of
the hand is applied against the abdominal wall, about eight or ten inches
in front of the stifle and just below the flank. Moderate pressure is used,
and if a hard, voluminous mass is felt, or if the foetus moves, it is a
sure sign that the animal is pregnant. It is not uncommon for the foetus to
show some movement in the morning, or after the animal drinks freely of
cold water. The increase in the volume of the udder occurs at a
comparatively early period in animals that are pregnant for the first time.
The secretion of milk and the dropping of the muscles of the quarters
indicate that parturition is near. The Abderhalden test for determining
whether or not an animal is pregnant is now practised.

HYGIENE OF PREGNANT ANIMALS.--Pregnant animals that are confined in a
pasture that is free from injurious weeds and not too rough or hilly, and
where the animals have access to clean water and the necessary shelter,
seldom suffer from an abnormal birth. Here they live under the most
favorable conditions for taking exercise, securing a suitable diet and
avoiding injury. It may not be possible in managing breeding animals to
provide such surroundings at all times, but we should observe every
possible hygienic precaution, especially if the animal has reached the
later periods of pregnancy.

All pregnant animals are inclined to be lazy, but, if permitted, will take
the necessary exercise. Pregnant mares are usually worked. Such exercise
does no harm, providing the work is not hard or of an unusual character.
Cows are usually subject to more natural conditions than other domestic
animals.

Protecting pregnant animals against injuries resulting from crowding,
slipping and fighting is an important part of their care. Injuries from
crowding together in the sleeping quarters and about feeding-troughs, or
through doors and climbing over low partitions are common causes of injury
in pregnant sows. Crowding together in the stable or yard, or through
doorways, fighting, and slipping on floors, or icy places sometimes results
in injury. It is rare, however, for cows to abort from an injury, but
parturition may not be completely free from disagreeable complications.
Under the conditions mentioned retention of the fetal membranes is common.

Ewes frequently suffer from too close confinement during late winter. Sows
are often subject to the most unhygienic conditions. This is shown in the
heavy death-rate in sows and pigs. During the late winter and early spring
the conditions may be such as not to permit of exercise. Stormy, snowy,
muddy weather is common at this season of the year. Persons caring for ewes
and sows should see that they take sufficient exercise. It may be necessary
to drive them about for a short time each day. At such times it may be
advisable to give them a laxative dose of oil, or give a laxative with the
feed. When there is any indication of constipation, this should be
practised.

Pregnant animals should be fed carefully. We may feed animals that are not
in this condition in a careless fashion, but if pregnant, over-feeding, the
feeding of a fattening ration, or spoiled feed, and sudden changes in the
feed can not be practised with any degree of safety. A bulky ration of dry
feed and drinking impure, or too little, water may cause constipation,
acute indigestion and abortion. The ration fed should contain the necessary
inorganic and organic elements for the building up of the body tissues of
the foetus.

At the end of the parturition period, separate quarters should be provided.
The mare or cow should be given a comfortable clean stall away from the
other animals. The ewe should be provided with a warm room if the weather
is cold. It is always best to give the sow a separate pen that is dry and
clean, and away from the other animals. All danger from injury to the
mother and young should be guarded against.

ABORTION.--The expulsion of the foetus at any time during the period of
gestation, when it is not sufficiently developed to live independently of
the mother, is termed abortion. Abortion may be either _accidental_ or
_infectious_. Accidental abortion is more commonly met with in the mare and
sow than the infectious form. In ruminants the opposite holds true.

_The causes of accidental abortion_ are faulty methods of feeding and care.
Injuries, acute indigestion, mouldy, spoiled feeds, chilling resulting from
exposure and drinking ice-cold water, nervousness brought on by fright, or
excitement and general diseases are the common causes of abortion.

_Infectious abortion_ is most common in cows. Other domestic animals that
may be affected are the mare, sow and ewe.

_It is caused_ by a specific germ. The _Bacillus abortus_ of Bang is the
cause of abortion in cows, but the specific germ that produces abortion in
other species of animals has not been proven. In this country, Keer, Good,
Giltner and others have proven that the Bang bacillus of abortion is
infectious for other species of animals, and outbreaks of this disease have
been said to occur among breeding ewes pastured and fed on infected
premises. Its infectiousness for the females of other species has never
been proven in natural outbreaks.

The disease-producing germs are present in the body of the foetus, the
fetal membranes, the discharge from the maternal passages, the faeces and
milk of aborting animals. The male may carry the infection in the sheath,
urethra and on the penis. The natural avenues of infection are the maternal
passages and digestive tract.

It is very seldom that abortion is carried from one herd to another by
means other than through the breeding of animals free from abortion to
animals affected by this disease. The purchase of a bull or cow from an
infected herd and breeding them to animals that are free from disease, is a
common method of spreading the disease. After serving the diseased animal,
the male may carry the bacillus of abortion into the maternal passages of
the next cow he serves. There are numerous cases on record where the bull
was a permanent carrier of the Bacillus abortus and infected nearly every
animal served. The distribution of the disease in the herd following the
introduction of a cow, sow, or ewe that has aborted before or after being
purchased, takes place through contact of the other animals with the virus
that may be present on the floor, or in the manure, or by taking the virus
into the digestive tract along with the feed and drinking water.
Experimental evidence indicates the latter avenue of infection.

The stallion is the most common source of infectious abortion in mares. An
infected stallion may distribute the disease to a large percentage of the
mares that he serves. For this reason nearly all of the mares in a certain
locality may abort.

In case the infection occurs at the time of service, the abortion usually
takes place during the first half of the period of pregnancy. Cows that
become pregnant without recovering from the inflammation of the lining
membrane of the genital tract, may abort at a very early period. McFadyean
and Stockman from the artificially inoculated cases of infectious abortion
in cows, showed that the period of incubation averaged 126 days.

_The symptoms of accidental abortion_ are extremely variable. Animals that
abort during the early periods of pregnancy may show so little disturbance,
that the animal can be treated as if nothing had happened. During the
latter half of pregnancy, and especially when the accident is caused by an
injury, the symptoms are more serious. Loss of appetite, dulness,
restlessness, abdominal pain and haemorrhage are the symptoms commonly
noted. If the foetus is dead, it may be necessary to assist the animal in
expelling it. In the latter case, death of the mother may occur.

A slight falling of the flanks, swelling of the lips of the vulva and a
retention of the fetal membranes, or discharge from the vulva may be the
only symptoms noted at the time abortion occurs.

_The symptoms of infectious abortion_ vary in the different periods of
pregnancy. At an early period, the foetus may be passed with so little
evidence of labor that the animal pays little attention to it. The
recurrence of heat may be the first intimation of the abortion. All cases
of abortion are followed by more or less discharge from the vulva. This is
especially true if the fetal membranes are retained. In such cases, the
discharge has a very disagreeable odor. In most cases the foetus is dead.
When born alive, it is weak and puny, and usually dies or is destroyed
within a few days. When the attendant fails to give the animal the
necessary attention, or is careless in his manipulation of the parts,
inflammation of the womb, caused by the decomposition of the retained
membranes, or the introduction of irritating germs on the ropes,
instruments and hands, may occur. Death commonly follows this complication.

It is very important that the infectious form be diagnosed early in the
outbreak. For all practical purposes we are justified in diagnosing
infectious abortion, if several animals in the herd abort, especially if it
follows the introduction of new animals. Methods of serum diagnosis, the
agglutination and complement-fixation tests, are now used in the diagnosis
of this disease.

_The preventive treatment_ of the accidental form consists in avoiding
conditions that may result in this accident. Pregnant animals should not be
exposed to injuries from other animals or from the surroundings. Animals
which show a predisposition to abort should not be bred. We should see that
all animals receive the necessary exercise and a proper ration.

If the animal indicates by her actions that abortion may take place, we
should give her comfortable, quiet quarters. It is very necessary to keep
her quiet, and if restless, morphine may be given. A very light diet should
be fed and constipation prevented by administering a laxative. The
necessary attention should be given in case abortion occurs.

The enforcement of _preventive_ or _quarantine measures_ is very important
in the control of infectious abortion. This is especially true of breeding
herds and dairy cows. Breeders do not recognize the importance of keeping
their herds clean or free from disease. It is a well-known fact among
stockmen that abortion and other infectious diseases have been frequently
introduced into the herd through the purchase of one or more breeding
animals. Because of the prevalence of infectious abortion among cows, it is
advisable to subject newly purchased breeding animals, or a cow that has
been bred outside of the herd, to a short quarantine period before allowing
them to mix with the herd. The breeding of cows from neighboring herds to
the herd bull is not a safe practice. In communities where there are
outbreaks of this disease, animals that abort, or show indications of
aborting, should be quarantined for a period of from two to three months.
The separation from the herd should be so complete as to eliminate any
danger of carrying the disease to the healthy animals on the clothing and
farm tools. If this method of control were practised at the very beginning
of the outbreaks, the disease could be checked in the large majority of
herds.

The foetus and membranes should be destroyed by burning. In case the animal
does not pass the fetal membranes, they should be completely removed. In
the cow, it is advisable to wait twenty-four hours before doing this. The
animal's stall should be thoroughly cleaned and disinfected. It is very
advisable to give the entire stable a thorough disinfecting. For this
purpose a three or four per cent water solution of liquor cresolis compound
may be used. It is advisable to apply it with a spray pump. The floor and
feed troughs should be sprinkled daily with the disinfectant. All manure
should be removed to a place where the animals can not come in contact with
it. It is not advisable to confine the cows to a small yard. The more range
they have the easier it is to control the disease.

_Individual treatment_ is very necessary. In infectious abortion the mucous
lining of the womb and the passages leading to it become inflamed. This
should be treated by irrigating the parts with a warm water solution of a
disinfectant that is non-irritating. This treatment should be repeated
daily for a period of from two to four weeks. We must be very careful not
to irritate the parts. A one-half per cent water solution of liquor
cresolis compound may be used.

Animals that abort should not be bred until they have completely recovered.
Small animals that have no special value as breeding animals should be
marketed. Cows and mares should not be bred for a period of at least three
months.

Infected males should not be used for service. The male should receive the
necessary attention in the way of irrigating the sheath before and after
each service.

PHYSIOLOGY OF PARTURITION.--Parturition or birth, when occurring in the
mare, is designated as foaling; in the cow, calving; in the sheep, lambing;
and in the sow, farrowing. A normal or natural birth occurs when no
complications are present and the mother needs no assistance. When the act
is complicated and prolonged, it is termed abnormal birth. The length of
time required for different individuals of the same species to give birth
to their young varies widely. It may require but a few minutes, or be
prolonged for a day or more. The cause of this variation in the length of
time required for different animals to bring forth their young, can be
better understood if we study the anatomy of the parts and their functions.

Throughout the pregnant period the _expulsion of the foetus_ is being
prepared for. As the foetus develops there is a corresponding development
of the muscular wall of the womb. The last period of pregnancy is
characterized by the relaxation of the muscles and ligaments that form the
pelvic walls, and a relaxation and dilation of the maternal passages. In
addition, degenerative changes occur in the structures that attach the
foetus to the womb, the normal structures being gradually destroyed by a
fatty degeneration. This results in a separation between the fetal and
maternal placenta. The contents of the womb begin to affect the organ in
the same manner as a foreign body, irritating the nerve endings and
producing contractions of the muscles. These contractions of the muscles
help greatly in breaking down the attachments until finally the labor pains
begin in earnest, and the foetus is gradually forced out of the womb,
through the dilated os and into the vagina and vulva.

_A normal birth_ is possible, only when the expelling power of the womb is
able to overcome the resistance offered by the foetus and its membranes,
the pelvic walls and the vagina and vulva.

[Illustration: FIG. 18.--Photograph of model of uterus of cow containing a
foetus: foetus; umbilical cord; placenta; horn containing foetus; and
opposite horn. Note the difference in the development of the two horns.]

The relative size of the foetus to the inlet of the pelvic cavity and its
position are the most important factors for the veterinarian and stockman
to consider (Fig. 18). On leaving the womb, the foetus passes into the
vagina and vulva. This portion of the maternal passages is situated in the
pelvic cavity which continues the abdominal cavity posteriorly. The pelvic
walls are formed by bones and ligaments that are covered by heavy muscles.
As previously mentioned, the ligaments and muscles relax toward the end of
pregnancy in order to prepare the way for the passage of the foetus. Before
entering the pelvis it is necessary for the foetus to be forced through the
inlet to this cavity. This is the most difficult part of the birth, as the
bones that form the framework of the pelvis completely enclose the entrance
to it. It is only in the young mother that the pelvic bones give way
slightly to the pressure on them by the foetus. It can be readily
understood, that when the young is large in proportion to the diameter of
the pelvic inlet, it is difficult for it to pass through. This occurs when
mothers belonging to a small breed, are impregnated by a sire belonging to
a large breed of animals. It may also occur if the mother is fed too
fattening a ration and not permitted sufficient exercise.

The part of the foetus that presents itself for entrance into the pelvic
cavity and its position are of the greatest importance in giving birth to
the young. Either end of the foetus, or its middle portion may be presented
for entrance. The _anterior_ and _posterior presentations_ may be modified
by the position that the foetus assumes. It may be in a position that
places the back or vertebrae opposite the upper portion of the inlet, or
the floor or sides of the pelvic cavity. These positions may be modified by
the position of one or both limbs, or the head and neck being directed
forwards instead of backwards. In the _transverse presentations_, the back,
or the feet and abdomen of the foetus may present themselves for entrance
to the pelvic cavity. These presentations may show three positions each.
The head may be opposite the upper walls of the inlet, the foetus assuming
a dog-sitting position, or it may lie on either side.

In order to overcome the friction between the foetus and the wall of the
maternal passages, these parts are lubricated by the fluids that escape
from the "water bags." If birth is prolonged and the passages become dry,
birth is retarded. The hair offers some resistance in a posterior
presentation. Young mares that become hysterical have abnormal labor pains
that seem to hold the foetus in the womb instead of expelling it.

CARE OF THE MOTHER AND YOUNG.--Although birth is generally easy in the
different domestic animals, it may be difficult and complicated, and it is
of the greatest economic importance that special attention be given the
mother at this time. It is very necessary for her to be free if confined in
a stall. If running in a pasture or lot, the necessary shelter from storms,
cold or extreme heat should be provided. Other farm animals, such as hogs,
horses and cattle, should not be allowed to run in the same lot or pasture.

When parturition commences, the mother should be kept under close
observation. If the labor is difficult and prolonged, we may then examine
the parts and determine the cause of the abnormal birth. Unnecessary
meddling is not advisable. Before attempting this examination, the hands
should be cleaned and disinfected, and the finger nails shortened if
necessary. The different conditions to be determined are the nature of the
labor pains, the condition of the maternal passages, and the position and
presentation of the foetus. In the smaller animals this examination may be
difficult. In prolonged labor the parts may be found dry and the labor
pains violent and irregular, or weak. The foetus may be jammed tightly into
the pelvic inlet, it may be well forward in the womb, the head and fore or
hind limbs may be directed backwards, or one or more of these parts may be
directed forward in such a position as to prevent the entrance of the
foetus into the pelvic inlet. Sometimes the foetus is in a transverse
position. The parts that present themselves at the pelvic inlet should be
carefully examined and their position determined. The necessary assistance
should then be given. Any delay in assisting in the birth may result in the
death of the young or mother, or both. On the other hand, unintelligent
meddling may aggravate the case and render treatment difficult or
impossible. There is no line of veterinary work that requires the attention
of a skilled veterinarian more than assisting an irregular or abnormal
birth.

The attendant must guard against infecting the parts with irritating germs,
or irritating and injuring them in any way. The hands, instruments, and
cords must be freed from germs by washing with a disinfectant, or
sterilization with heat. The quarters must be clean in order to prevent
contamination of the instruments and clothing of the attendant by filth.
Extreme force is injurious. For illustration, we may take a case of
difficult birth caused by an unusually large foetus. Both presentation and
position are normal, the forefeet and head having entered the pelvic
cavity, but the shoulders and chest are jammed tightly in the inlet, and
the progress of the foetus along the maternal passages is retarded. By
using sufficient force, we may succeed in delivering the young, but by
pulling on one limb until the shoulder has entered the pelvis, and
repeating this with the opposite limb we are able to deliver the young
without exposing the mother to injury. It may be necessary to change an
abnormal presentation, or position, to a normal presentation, or as nearly
normal as possible. This should be done before any attempt is made to
remove the foetus.

Following birth the mother should not be unnecessarily disturbed. The
quarters should be clean, well bedded and ventilated, but free from
draughts. If the parturition has been normal, a small quantity of easily
digested feed may be fed. If weak and feverish, feed should be withheld for
at least twelve hours. The mare should be rested for a few weeks. The young
needs no special attention if it is strong and vigorous, but if weak, it
may be necessary to support it while nursing, or milk the mother and feed
it by hand. If the mother is nervous and irritable, it may be necessary to
remove the young temporarily to a place where she can hear and see it,
until a time when she can be induced to care for it. The principal
attention required for young pigs is protection against being crushed by
the mother. The cutting off and ligation of the umbilical cord at a point a
few inches from the abdomen, and applying tincture of iodine or any
reliable disinfectant is very advisable in the colt and calf.

RETENTION OF THE FETAL MEMBRANES.--The foetus is enveloped by several
layers of membranes. The _external envelope, the chorion_, is exactly
adapted to the uterus. The _innermost envelope, the amnion_, encloses the
foetus. Covering the external face of the amnion and lining the inner face
of the chorion is a double membrane, _the allantois_. The envelopes
mentioned are not the only protection that the foetus has against injury.
It is enveloped in fluids as well. Immediately surrounding it is the
_liquor amnii_, and within allantois is the _allantoic fluid._

[Illustration: FIG. 19.--Placenta of cow.]

_The placenta_ is a highly vascular structure spread out or scattered over
the surface of the chorion and the mucous membrane of the uterus, that
attaches the foetus and its envelopes to the womb (Fig. 19). It is by means
of this vascular apparatus that the foetus is furnished with nourishment.
The fetal and maternal placentas are made up of vascular villi and
depressions that are separated only by the thin walls of capillaries, and a
layer of epithelial cells. This permits a change of material between the
fetal and maternal circulation. The arrangement of the placenta differs in
the different species. In the mare and sow, the villi are diffused. In
ruminants, the villi are grouped at certain points. These vascular masses
are termed cotyledons. The maternal cotyledons or "buttons" form appendages
or thickened points that become greatly enlarged in the pregnant animal.

Toward the end of the pregnant period, the attachments between the fetal
and maternal placentulae undergo a fatty degeneration and finally separate.
This results in contractions of the muscular wall of the uterus, and the
expulsion of the foetus and its envelopes. In the mare, it is not uncommon
for the colt to be born with the covering intact. This does not occur in
the cow. Usually the envelopes are not expelled until a short time after
birth in all animals, and it is not uncommon for them to be retained. This
complication is most commonly met with in the cow.

In the mare the _retention of the fetal envelopes_ or "afterbirth" is
commonly due to the muscles of the womb not contracting properly following
birth. Abortion, especially the infectious form, is commonly complicated by
a retention of the fetal membranes. Any condition that may produce an
inflammation of the lining membrane of the womb may result in retention of
the "after-birth." Injuries to the uterus resulting from the animal
slipping, fighting and becoming crowded are, no doubt, common causes of
failure to "clean" in cows.

_The symptoms_ are so marked that a mistaken diagnosis is seldom made. A
portion of the membranes is usually seen hanging from the vulva, and the
tail and hind parts may be more or less soiled. The latter symptom is
especially prominent if the membranes have been retained for several days,
and decomposition has begun. In such case, the discharge from the vulva is
dark in color, contains small pieces of the decomposed membrane and has a
very disagreeable odor. In the mare, acute inflammation of the womb may
result if the removal of the "after-birth" is neglected. Loss of appetite,
abnormal body temperature, weakness and diarrhoea may follow. Such cases
usually terminate in death. Retention of the fetal membranes is a very
common cause of leucorrhoea.

_The treatment_ consists in removing the fetal envelopes before there is
any opportunity for them to undergo decomposition. In the mare, this should
be practised within a few hours after birth has occurred, and in other
animals, from one to forty-eight hours. In warm stables and during the warm
weather, treatment should not be postponed later than twenty-four hours.
The only successful method of treatment is to introduce the hand and arm
into the uterus, and break down the attachments with the fingers. In the
larger animals, the use of the arm must not be interfered with by clothing.
Every possible precaution should be taken to prevent infection of the
genital organs with irritating germs. It is advisable in most cases to
flush out the womb with a one per cent water solution of liquor cresolis
compound after the removal of the fetal envelopes.

LEUCORRHOEA.--This is a chronic inflammation of the mucous membrane lining
the genital tract, that is associated with more or less of a discharge from
the vulva. It is common in animals that abort, or retain the "after-birth."

The discharge may be white, sticky, albuminous, and without odor, or it may
be chocolate colored and foul smelling. The tail and hind parts are usually
soiled with it. In chronic inflammation of the womb the discharge is
intermittent. In mild cases the health of the animal is in no way impaired.
Sterility is common. Loss of appetite and unthriftiness occur in severe
cases.

_Treatment_.--Mild cases readily yield to treatment. This consists in
irrigating the maternal passages with a one-half per cent warm water
solution of liquor cresolis compound. This treatment should be repeated
daily and continued for as long a time as necessary.

MAMMITIS.--Inflammation of the mammary gland or udder is more common in the
cow than in any of the other domestic animals. In all animals it is most
frequently met with during the first few weeks after birth.

_A predisposing cause_ in the development of mammitis is a high development
of the mammary glands. The following _direct causes_ may be mentioned:
incomplete milking, or milking at irregular intervals; injury to the udder
by stepping on the teat; blows from the horns and pressure caused by lying
on a rough, uneven surface; chilling of the udder by draughts and lying on
frozen ground; and infection of the glandular tissue by _irritating germs_.
The latter cause produces the most serious, and, sometimes, a very
extensive inflammation. This form of inflammation may spread from one cow
to another, causing the milk to be unfit for food, and bringing about the
loss of one or more quarters of the udder.

_The symptoms_ occurring in the different forms of mammitis differ. The
inflammation may involve one or more of the glands, and may affect either
the glandular or the connective tissue. In some cases the gland may appear
congested for a few days before the inflammatory changes occur. The part
becomes hot, swollen, tender and reddened. It may feel doughy or hard. If
the connective tissue is involved (interstitial form), there is apt to be a
high body temperature, the udder may be much larger than normal, is tender
and pits on pressure. Loss of appetite usually accompanies this form of
mammitis. Very little or no milk is secreted. Sometimes, the milk is
greatly changed in appearance, is foul smelling and contains pus. In
congestion of the udder and rupture of the capillary vessels, the milk may
contain blood.

Mild inflammation of the udder responds readily to treatment. The
interstitial form may terminate in abscesses and gangrene. The replacement
of the glandular tissue by fibrous tissue in one or more quarters is not
uncommon. Death seldom occurs.

_The preventive treatment_ consists in avoiding conditions that may favor
or cause an inflammation of the gland. Animals that have highly developed
mammary glands should be fed a light diet just before and following
parturition. Following parturition, a dose of Epsom or Glauber's salts may
be given. If the young does not take all the milk, the udder should be
milked out as clean as possible. Massaging the udder by kneading or
stroking may be practised.

The following _treatment_ is recommended: The application of a thick
coating of antiphlogistin once or twice daily is a useful remedy. If the
udder becomes badly swollen, it should be supported with a bandage.
Extensive inflammation may be treated by the application of cold in the
form of packs of cracked ice. Irrigating the gland with a four per cent
water solution of boric acid is an important treatment for certain forms of
mammitis. Abscess formation or suppuration should be promptly treated by
opening and treating the abscesses. If gangrene occurs, it may be necessary
to remove a part, or the whole of the udder.

The giving of milk discolored with blood may be treated by applying
camphorated ointment twice daily.

SORE AND WARTY TEATS.--Irritation to the teats by filth, cold, moisture and
injuries cause the skin to become inflamed, sore and scabby.

_Preventive treatment_ is the most satisfactory. Sore teats may be treated
by applying the following ointment after each milking: vaseline ten parts
and oxide of zinc one part. Pendulous warts may be clipped off with a sharp
pair of scissors. Castor oil applied to the wart daily by rubbing may be
used for the removal of flat warts.

"MILK-FEVER" OR POST-PARTUM PARALYSIS.--This is a disease peculiar to cows,
especially heavy milkers that are in good condition. It most commonly
occurs after the third, fourth and fifth calving. The disease usually
appears within the first two or three days after calving, but it has been
known to occur before, and as late as several weeks after calving. The
cause is not certainly known. The Schmidt theory is that certain toxins are
formed in the udder, owing to the over activity of the cells of the
glandular tissue.

[Illustration: FIG. 20.--A case of milk-fever.]

_The symptoms_ are characteristic of the disease. At the very beginning of
the attack the cow stops eating and ruminating, becomes uneasy, switches
the tail, stamps the feet, trembles, staggers when forced to walk and
finally falls and is unable to get up. At first she may lie in a natural
position; later, as the paralytic symptoms become more pronounced, the head
is laid against the side of the body and the animal seems to be in a deep
sleep (Fig. 20). In the more severe form the cow lies on her side,
consciousness is lost and the paralysis of the muscles is marked. The
different body functions are interfered with; the urine is retained,
bloating occurs, respirations are slow, pulse weak and temperature
subnormal or normal.

_Preventive treatment_, such as feeding a spare diet during the latter
period of pregnancy, is not always advisable. Heavy milkers should be given
one-half pound of Glauber's salts a day or two before calving, and the dose
repeated when the cow becomes fresh. Cows affected with milk-fever seldom
die if treated promptly.

The _treatment_ consists in emptying the udder by milking and injecting air
or oxygen gas into the gland until it is completely distended (Fig. 21).
The milk-fever apparatus should be clean, and the air injected filtered.
Before introducing the milking tube into the milk duct, the udder should
first be washed with a disinfectant, and a clean towel laid on the floor
for the gland to rest on. After injecting the quarter, strips of muslin or
tape should be tied around the ends of the teats to prevent the escape of
the air. If the cow does not show indications of recovery in from four to
five hours, the treatment should be repeated.

[Illustration: FIG. 21.--Milk-fever apparatus: pump; filter; rubber tubing;
and milk tube.]

It is very necessary to give the cow a comfortable stall and protect her
from any kind of exposure. No bulky drenches should be administered. If she
lies stretched out, the fore parts should be raised by packing straw under
her. This is necessary in order to prevent pneumonia, caused by
regurgitated feed entering the air passages and lungs. It is very advisable
to give her the following mixture for a few days after the attack: tincture
of nux vomica two ounces, and alcohol six ounces. One ounce of this mixture
may be given four times daily in a little water.


QUESTIONS

 1. Name the generative organs of the female.

 2. Name the generative organs of the male.

 3. Give the causes of sterility or impotency in the male and female.

 4. Give the treatment of impotency in the male and female.

 5. Describe the probable signs of pregnancy; positive signs of pregnancy.

 6. Describe the hygienic care of the pregnant female in a general way.

 7. Name the different forms of abortion; give the causes.

 8. Describe the preventive treatment of infectious abortion.

 9. Give a general discussion of the physiology of parturition.

10. What are the common causes of difficult birth?

11. What parts of the foetus may present themselves at the inlet of the
    pelvic cavity? What are the different positions of the foetus?

12. What attention should be given the mother at the time of parturition?

13. What attention should be given the young immediately after birth?

14. Give the causes of retention of the fetal membranes; state the method
    of removing them.

15. Give the causes and treatment of inflammation of the udder.

16. Give the cause of milk-fever; give the treatment.



CHAPTER VIII

DISEASES OF THE RESPIRATORY APPARATUS


GENERAL DISCUSSION.--The respiratory apparatus may be divided into two
groups of organs, anterior and posterior. The anterior group, the
_nostrils, nasal cavities, pharynx, larynx_ and _trachea_, is situated in
the region of the head and neck. The posterior group, the _bronchial tubes_
and _lungs_, is situated in the chest or thoracic cavity.

_The nostrils_ are the anterior openings of the air passages. The nasal
cavities are situated in the anterior region of the head, and extend the
entire length of the face. Each cavity is divided into three long, narrow
passages by the two pairs of turbinated bones. The lining membrane is the
nasal mucous membrane, the lower two-thirds or respiratory portion
differing from the upper one-third, in that the latter possesses the nerve
endings of the olfactory nerve and is the seat of smell. The five pairs of
head sinuses communicate with the nasal cavities. Posteriorly and near the
superior extremity of the nasal passages, are two large openings, the
guttural, that open into the pharyngeal cavity.

_The pharynx_ is a somewhat funnel-shaped cavity. The walls are thin and
formed by muscles and mucous membrane. This is the cross-road between the
digestive and respiratory passages. In the posterior portion of the cavity
there are two openings. The inferior opening leads to the larynx and the
superior one to the oesophagus. All feed on its way to the stomach must
pass over the opening into the larynx. It is impossible, however, for the
feed to enter this opening, unless accidentally when the animal coughs. The
cartilage closing this opening is pressed shut by the base of the tongue
when the bolus of feed is passed back and into the oesophageal opening.

_The larynx_ may be compared to a box open at both ends. The several
cartilages that form it are united by ligaments. It is lined by a mucous
membrane. The posterior extremity is united to the first cartilaginous ring
of the trachea. The anterior opening is closed by the epiglottis. Just
within is a V-shaped opening that is limited laterally by the folds of the
laryngeal mucous membrane, the vocal chords.

_The trachea_ is a cylindrical tube originating at the posterior extremity
of the larynx, and terminating within the chest cavity at a point just
above the heart in the right and left bronchial tubes. It is formed by a
series of cartilaginous rings joined together at their borders by ligaments
and lined by a mucous membrane.

_The bronchial tubes_ resemble the trachea in structure. They enter the
lungs a short distance from their origin, where they subdivide into
branches and sub-branches, gradually decreasing in calibre and losing the
cartilaginous rings, ligaments and muscular layer until only the thin
mucous membrane is left. They become capillary in diameter, and finally
open into the infundibula of the air cells of the lungs.

_The lungs_ take up all of the space in the thoracic cavity not occupied by
the heart, blood-vessels and oesophagus. This cavity resembles a cone in
shape that is cut obliquely downwards and forward at its base. The base is
formed by the diaphragm which is pushed forward at its middle. It is lined
by the pleura, a serous membrane, that is inflected from the wall over the
different organs within the cavity. The median folds of the pleura divide
the cavity into right and left portions. A second method of describing the
arrangement of the pleura is to state that it forms two sacks, right and
left, that enclose the lungs. The lungs are the essential organs of
respiration. The tissue that forms them is light, will float in water, is
elastic and somewhat rose-colored. Each lung is divided into lobes, and
each lobe into a great number of lobules by the supporting connective
tissue. The lobule is the smallest division of the lung and is formed by
capillary bronchial tubes, air cells and blood-vessels. It is here that the
external respiration or the exchange of gases between the capillaries and
the air cells occurs.

VENTILATION.--It is agreed by all persons who have investigated the
subject, that unventilated stable air is injurious to animals. At one time
it was believed that the injurious effects resulting from the breathing of
air charged with gases and moisture from the expired air and the animal's
surroundings, were due to a deficiency in oxygen. It is now believed that
the ill-effects are mainly due to the stagnation of air, the humid
atmosphere, and the irritating gases emanating from the body excretions.

The common impurities found in _stable air_ are carbonic and ammonia gas,
moisture charged with injurious matter and dust from the floor and bodies
of the animals. As a rule, the more crowded and filthy the stable, the more
impurities there are in the air. If any of the animals are affected with an
infectious disease, such as tuberculosis or glanders, the moisture and dust
may act as carriers of the disease-producing germs. Infectious diseases
spread rapidly in crowded, poorly ventilated stables. The two factors
responsible for this rapid spread of disease are the lowered vitality of
the animal, due to breathing the vitiated air, and the greater opportunity
for infection, because of the comparatively large number of bacteria
present in the air.

_The purpose of stable ventilation_ is to replace the stable air with purer
air. The frequency with which the air in the stable should be changed
depends on the cubic feet of air space provided for each animal, and the
sanitary conditions present. The principal factor in stable ventilation is
the force of the wind. In cold weather it is very difficult to properly
ventilate a crowded stable without too much loss of animal heat and
creating draughts.

For practical purposes, the _need of ventilation_ in a stable can be
determined by the odor of the air, the amount of moisture present and the
temperature. It is impossible to keep the air within the stable as pure as
the atmosphere outside.

All dangers from injury by breathing impure air, or by draughts can be
eliminated by proper stable construction, attention to the ventilation and
keeping the quarters clean.

[Illustration: FIG. 22.--A case of catarrhal cold.]

CATARRH (COLD IN THE HEAD).--Catarrh is an inflammation of the mucous
membrane lining the nasal cavities that usually extends to the membrane
lining of the sinuses of the head. It may be acute or chronic. The
inflammation very often extends to the pharynx and larynx. Cold in the head
is more common in the horse than in any of the other animals (Fig. 22).

_The most common causes_ of "colds" are standing or lying in a draught,
becoming wet, and exposure to the cold. "Colds" are common during cold,
changeable weather. Horses that are accustomed to warm stables, are very
apt to take "cold" if changed to a cold stable and not protected with a
blanket. Most animals are not affected by the cold weather if given dry
quarters and a dry bed. Irritation to the mucous membrane by dust, gases
and germs is a common cause. Influenza and colt distemper are characterized
by an inflammation of the respiratory mucous membranes. In the horse,
chronic catarrh is commonly caused by diseased teeth, and injuries to the
wall of the maxillary sinus. In sheep, the larvae of the bot-fly may cause
catarrh.

_The early symptoms_ usually pass unnoticed by the attendant. The lining
membrane of the nostrils is at first dry and red. During this stage
sneezing is common. In a few days a discharge appears. This is watery at
first, but may become catarrhal, heavy, mucous-like and turbid. In severe
cases it resembles pus. The lining membrane of the eyelids appears red and
tears may flow from the eye. Sometimes the animal acts dull and feverish,
but this symptom does not last longer than one or two days unless
complicated by sore throat.

_Inflammation of the throat_ is a common complication of "colds." It is
characterized by difficulty in swallowing and partial, or complete loss of
appetite. Drinking or exercising causes the animal to cough. If the larynx
as well as the pharynx is inflamed, distressed and noisy breathing may
occur. Pressure over the region of the throat causes the animal pain.

Common "cold" terminates favorably within a week. Chronic catarrh may
persist until the cause is removed and the necessary local treatment
applied. Inflammation of the pharynx and larynx may persist for several
weeks unless properly treated. Abscesses may form in the region of the
throat. Horses frequently become thick winded as a result of severe attacks
of sore throat.

_The treatment_ is both preventive and curative. "Colds" and sore throat
can be largely prevented by good care, exercise and properly ventilated
stables. Mild cases require a light diet, comfortable quarters and a dry
bed. Allowing the animal to inhale steam three or four times daily is
useful in relieving the inflammation. Easily digested feeds, and in case
the animal has difficulty in swallowing, soft feeds and gruels, should be
given. The throat may be kept covered with a layer of antiphlogistin and
bandaged. Glycoheroin may be given in from teaspoonful to tablespoonful
doses, depending on the size of the animal. Chlorate of potassium may be
given in the drinking water.

If the animal becomes run down in flesh, as sometimes occurs in chronic
catarrh, bitter tonics should be given. In the latter disease, it is
sometimes necessary to trephine and wash out the sinus or sinuses affected
with an antiseptic solution. It may be necessary to continue this treatment
for several weeks.

BRONCHITIS.--Inflammation of the bronchial tubes may be either acute or
chronic. Acute bronchitis is especially common in the horse, while the
chronic form is more often met with in the smaller animals, especially
hogs. This disease is most common among horses during the changeable
seasons of the years. It is _caused_ by warm, close stables or stalls, and
irritating gases emanating from the floor, or manure in the stall. In
general, the causes are about the same as in cold in the head. In young
animals and hogs, the inhalation of dust, and bronchial and lung worms
commonly cause it. Verminous bronchitis usually becomes chronic.

_In the acute form_ of the disease the _symptoms_ come on very quickly, the
fever is high and the pulse beats and respirations are rapid. Chilling of
the body occurs, and the animal may appear dull and refuse to eat. The
animal coughs frequently. Recovery occurs within a few days, unless
complicated by sore throat and pneumonia. In the horse, bronchitis is not a
serious disease, but in other animals recovery is delayed and complications
are more common.

_In chronic bronchitis_ in the horse, the animal coughs frequently, there
is more or less discharge from the nostrils and the respirations may become
labored when exercised. The animal is usually weak, in poor flesh and unfit
for work. In other cases, symptoms of broken wind are noticed. Severe
coughing spells on getting up from the bed, or on moving about are
characteristic of bronchitis in hogs. Verminous bronchitis in calves and
lambs is characterized by severe spells of coughing, difficult and labored
breathing and a weak, emaciated condition.

_The preventive treatment_ is the same as for "colds." In the acute form
the treatment consists largely in careful nursing. Properly ventilated,
clean quarters that are free from dust should be provided. The animal
should be covered with a light or heavy blanket, depending on the
temperature of the stable, and the limbs bandaged. A light diet should be
fed for a few days. It is advisable to give the animal a physic of oil. The
inhalation of steam every few hours during the first few days should be
practised. Glycoheroin may be given three or four times a day.

Animals affected with chronic bronchitis should not be exercised or worked.
We should guard against their taking cold, give nourishing feeds, and a
tonic if necessary.

CONGESTION OF THE LUNGS.--Pulmonary congestion is generally due to
overexertion and exposure to extreme heat or cold. It may occur if the
animal is exercised when sick or exhausted. Hogs that are heated from
exercise and allowed access to cold water, may suffer from a congestion or
engorgement of the lungs. It may be present at the beginning of an attack
of pneumonia or pleurisy.

_The symptoms_ are difficult breathing and the animal fights for its
breath. The body temperature may be several degrees above the normal. In
the mild form, the above symptoms are not so marked. The onset and course
of the disease are rapid, recovery, pneumonia, or death often occurring
within twenty-four hours.

_Pulmonary haemorrhage_ is not uncommon. The discharge from the nostrils
may be slightly tinged with blood, or there may be an intermittent
discharge of blood from the nostrils or mouth. The mucous membranes are
pale, the animal trembles and shows marked dyspnoea.

_The preventive treatment_ consists in using the proper judgment in caring
for, and in working or exercising animals. This is especially true if the
animal is affected with acute or chronic disease. At the very beginning,
bleeding should be practised. Hot blankets renewed frequently and bandages
to the limbs is a very necessary part of the treatment. In case of severe
pulmonary haemorrhage, treatment is of little use.

PNEUMONIA.--Inflammation of the lungs is more common in horses than in any
of the other domestic animals. The croupous form is the most common. The
inflammation may affect one or both lungs, one or more lobes, or scattered
lobules of lung tissue. The inflammation may be acute, subacute or chronic.

_The causes_ are very much the same as in other respiratory diseases.
Exposure to cold and wet, stable draughts, becoming chilled after
perspiring freely and washing the animal with cold water are the common
causes of pneumonia. Inflammation of the lungs is especially apt to occur
if the animal is not accustomed to such exposure. Animals affected with
other respiratory diseases are predisposed to pneumonia. Drenching animals
by way of the nostril and irritating drenches, or regurgitated feed passing
into the air passages and lungs are the traumatic causes of pneumonia.

_The symptoms_ vary in the different forms of pneumonia. In case pneumonia
occurs secondarily, the earliest symptoms are confounded with those of the
primary disease. The first symptoms noticed may be a high body temperature,
as indicated by chills, and refusing to eat. The visible mucous membranes
are red and congested, the nostrils dilated, the respirations quickened and
difficult, the expired air hot and the pulse beats accelerated. The animal
coughs, and in the horse, a rusty discharge may be noticed adhering to the
margins of the nostrils. The horse refuses to lie down if both lungs are
inflamed. In severe cases the expression of the face indicates pain, the
respirations are labored, the general symptoms aggravated, and the animal
stands with the front feet spread apart. Cattle are inclined to lie down,
unless the lungs are seriously affected. Hogs like to burrow under the
litter.

_The course of croupous pneumonia_ is typical, and unless it terminates
fatally in the first stage, the periods of congestion, hepatization and
resolution follow each other in regular manner. Auscultation of the lungs
is of great value in diagnosing and watching the progress of the disease.
It is more difficult to determine the character of the lung sounds in the
horse and cow than it is in the small animals. This is especially difficult
if the animal is fat. During the period of _congestion_ which lasts about a
day, one can hear both healthy and crepitating sounds. The period of
_hepatization_ is characterized by an absence of sound over the diseased
area. The inflammatory exudates become organized at the beginning of this
stage, and the air can not enter the air cells. This period lasts several
days. _Resolution_ marks the beginning of recovery or convalescence. Toward
the end of the second period, the inflammatory exudate in the air cells has
begun to degenerate. In the last stage, these exudates undergo liquefaction
and are absorbed, or expelled by coughing, in from seven days to two weeks,
depending on the extent of the inflammation and the general condition of
the animal.

_In the subacute form_ the symptoms are mild and may subside within a week.
Sometimes _abscesses_ form in the lung. _Gangrenous inflammation_ of the
lung can be recognized by the odor of the expired air and the severity of
the symptoms. This form of pneumonia terminates fatally. If the larger
portion of the lung tissue is inflamed, death from asphyxia may occur in
the second stage.

The success in the _treatment_ of pneumonia depends largely on the care.
Properly ventilated, clean, comfortable quarters and careful nursing are
highly important. Large animals should be given a roomy box stall. Cold
does not aggravate pneumonia, providing the animal's body is well protected
with blankets and the limbs bandaged. Wet, damp quarters and draughts are
injurious. Hogs should be given plenty of bedding to burrow in. A light,
easily digested diet should be fed. Very little roughage should be fed. If
the animal does not eat well, it may be given eggs and milk. Weak pulse
beats should be treated by giving digitalis and strychnine.
Counterirritation to the chest wall is indicated. During convalescence,
bitter tonics may be given. Constipation should be treated by giving the
animal castor or linseed oil.

PLEURISY.--Inflammation of the pleura is most common in horses. It occurs
in all farm animals and is frequently unilateral. There are two forms of
pleurisy, acute and chronic. Pleuropneumonia is common when the cause is a
specific germ. This occurs in tuberculosis, pleuropneumonia of horses and
pneumococcus infection.

_The common causes_ are exposure to cold, chilling winds, draughty, damp
quarters, and drinking cold water when perspiring. Injuries to the costal
pleura by fractured ribs and punctured wounds may cause it to become
inflamed.

The early symptoms of acute pleurisy are chills, rise in body temperature,
pain and abdominal breathing. The most characteristic symptom is the ridge
extending along the lower extremities of the ribs (pleuritic ridge). The
animal does not stand still as in pneumonia, but changes its position
occasionally, its movements in many cases being accompanied by a grunt.
Pressure on the wall of the chest causes the animal to flinch and show
evidence of severe pain. Large animals rarely lie down. The cough is short
and painful. On placing the ear against the wall of the chest and listening
to the respirations, we are able to hear friction sounds. After a few days
effusion occurs in the pleural cavity. Although the animal may have refused
to eat up to this time, it now appears greatly relieved and may offer to
eat its feed. This relief may be only temporary. If the fluid exudate forms
in sufficient quantity to cause pressure on the heart and lungs and
interfere with their movement, the pulse beat is weak, the respirations
quick and labored, the elbows are turned out and the feet are spread apart.
All of the respiratory muscles may be used. The expression of the face may
indicate threatened asphyxia. We may determine the extent of the pleural
exudate by auscultation. There is no evidence of respiratory sounds in that
portion of the chest below the surface of the fluid. Dropsical swellings
may occur on the under surface of the breast and abdomen.

_In subacute cases_ evidence of recovery is noted in from four to ten days.
_Acute pleurisy_ very often terminates fatally. Under the most favorable
conditions, recovery takes place very slowly, sometimes extending over a
period of several months. It is not uncommon for the horse to continue
having "defective wind."

_The treatment_ consists in good care, well ventilated quarters and careful
nursing, the same as recommended in the treatment of pneumonia. At the very
beginning, the pain may be relieved by the administration of small doses of
morphine. If the conditions in the stable permit, a hot blanket that has
been dipped in hot water and wrung out as dry as possible, may be applied
to the chest wall and covered with a rubber blanket. This treatment should
be continued during the first few days of the inflammation. These
applications may be reinforced by occasionally applying mustard paste to
the sides of the chest.

The animal should be allowed to drink but a limited amount of water. The
feed must be highly nutritious. Milk and eggs should be given if necessary.
A laxative dose of oil should be given. Calomel, aloes, and digitalis are
recommended when the effusion period approaches in order to increase the
elimination of fluid, and lessen its entrance into the body cavity. If the
amount of effusion is large, puncture of the thoracic cavity with a trocar
and cannula may be practised. This operation should be performed carefully,
and all possible precautions used against infection of the wound. During
the later period of the disease iodide of potassium, iron and bitter tonics
should be given.

BROKEN-WIND, HEAVES.--The terms broken-wind and heaves are used in a way to
include a number of different diseases of the respiratory organs of the
horse. The term heaves is applied almost wholly to an emphysematous
condition of the lungs. Broken-wind may include the following diseased
conditions: obstruction of the nasal passages by bony enlargements and
tumors; tumors in the pharynx; enlarged neck glands; collection of pus in
the guttural pouches and paralysis of the left, or both recurrent nerves
(roaring).

_The common causes_ of heaves are pre-existing diseases of the respiratory
organs, severe exercise when the animal is not in condition and wrong
methods of feeding. Heaves is more common in horses that are fed heavily on
dusty timothy and clover hay and allowed to drink large quantities of water
after feeding, than in horses that are fed green feeds, graze on pastures
or receive prairie hay for roughage. Chronic indigestion seems to aggravate
the disease. Over-distention of the stomach and intestines due to feeding
too much roughage and grain interferes with respiration. Severe exercise
when in this condition may result in over-distention, dilation and rupture
of the air cells. This is the most common structural change met with in the
lungs of horses affected with heaves. It is termed emphysema.

_The common symptoms_ noted are the double contraction of the muscles of
the flank with each expiration, a short, dry cough and the dilated
nostrils. The frequent passage of gas is a prominent symptom in
well-established cases of heaves. Chronic indigestion is commonly present
in heavy horses that are not well cared for, or are given hard work. This
condition aggravates the distressed breathing.

Heaves is a permanent disorder, but it may be relieved by climatic changes
and careful attention to the animal's diet.

The following _preventive treatment_ is recommended: Dusty hay should not
be fed to horses. Clover hay is not a safe feed for horses that are worked
hard. When starting on a drive after feeding, the horse should not be
driven fast, but allowed to go slowly for a few miles.

The symptoms can be greatly relieved by careful attention to the diet. A
limited quantity of roughage should be fed, and this should be good in
quality and fed in the evening. During the warm weather, the animal should
be watered frequently. After quitting work in the evening the animal may be
allowed to drink as much water as it wants. Plenty of grain, soft feed and
roots may be fed. A small handful of flaxseed meal given with the feed
helps in keeping down constipation. Fowler's solution of arsenic may be
given twice daily with the feed, in half-ounce doses for a period of ten
days or two weeks. Chronic indigestion should be combated by digestive
tonics.


QUESTIONS

1. Name the organs that form the anterior and posterior air passages.

2. To what conditions are the injurious effects of keeping animals in a
   poorly ventilated stable due?

3. State the purpose of ventilation. How can the need of ventilation be
   determined in a stable?

4. State the causes of "cold" in the head; give the treatment.

5. State the cause of bronchitis; give the treatment.

6. What are the causes of pneumonia? Describe the symptoms and treatment.

7. What symptoms are characteristic of pleurisy? Give the treatment for
   pleurisy.

8. Give the causes and treatment of "heaves."



CHAPTER IX

DISEASES OF THE CIRCULATORY ORGANS


GENERAL DISCUSSION.--The circulatory organs are the heart, arteries, veins
and lymphatics. The _heart_ is the central organ of the circulatory system
(Fig. 23). Its function is to force the blood through the blood-vessels. It
is situated in the thoracic cavity between the lungs, and enclosed by a
special fold of the pleura, the pericardial sack. There are two kinds of
blood-vessels, arteries and veins. The _arteries_ leave the heart and carry
the blood to the many different organs of the body. The _veins_ return to
the heart and carry the blood from the body tissues. The _capillaries_ are
small blood-vessels, microscopic in size, that connect the arteries with
the veins. The arteries carry the pure blood. The opposite is true,
however, of the lesser or pulmonary system. The pulmonary artery carries
the impure blood to the lungs, and the pulmonary veins carry the pure blood
back from the lungs. The _lymphatic vessels_ carry a transparent or
slightly colored fluid and chyle from the tissues and alimentary canal.
This system of vessels empties into the venous system.

[Illustration: FIG. 23.--Photograph of model of horse's heart: auricle;
ventricle; pulmonary artery; pulmonary veins; posterior aorta; and anterior
aorta.]

_The functions of the blood_ are to nourish the body tissues; furnish
material for the purpose of the body secretions; supply the cells of the
body with oxygen; convey from the tissues injurious substances produced by
the cellular activity; and destroy organisms that may have entered the body
tissues. The cellular and fluid portions of the blood are not always
destructive to disease-producing organisms. In certain infectious diseases,
the fluid portion of the blood may contain innumerable organisms, and
destruction of the blood cells occurs.

_In inflammation_ of tissue the circulation of the blood in the inflamed
part undergoes certain characteristic changes. At the beginning there is an
increase in the blood going to the part. This is followed by a slowing of
the blood stream in the small vessels, and the collecting of the blood
cells in the capillaries and veins. These circulatory changes are followed
by the migration of the blood cells, and the escape of the fluid portion of
the blood into the surrounding tissue. The character of the above
circulatory changes depends on the extent of the injury to the tissue.

PALPITATION.--This disturbance in domestic animals seems to be purely
functional. It may occur independent of any organic heart disease. A highly
nervous condition, excitement, over-exertion, debility from disease and the
feeding of an improper ration are the common causes.

The heart beats are so violent and tumultuous as to shake the body, and be
noticed when standing near the animal. The heart sounds are louder than
normal and the pulse beats small and irregular. It may be differentiated
from spasm of the diaphragm by determining the relationship of the heart
beats to the abrupt shocks observed in the costal and flank regions.

_The treatment_ consists in keeping the animal quiet and avoiding any
excitement. A quiet stall away from the other animals is best. The
treatment of palpitation resulting from some organic heart disease must be
directed largely at the original disease. Morphine is commonly used for the
treatment of this disorder. Weak, anaemic animals should receive blood and
bitter tonics. If we have reason to believe that the disturbance is caused
by improper feeding, the animal should receive a spare diet for a few days.
In such cases it is advisable to administer a physic.

PERICARDITIS.--Inflammation of the pericardial sack is usually a secondary
disease. It is frequently met with in influenza, contagious
pleuropneumonia, hog-cholera and rheumatism. Cattle may suffer from
traumatic pericarditis caused by sharp, pointed, foreign bodies passing
through the wall of the reticulum and penetrating the pericardial sack. The
jagged ends of fractured ribs may cause extensive injury to neighboring
parts, and the inflammation spreads to the pericardial sack.

_The symptoms_ of pericarditis may not be recognized at the very beginning
when the disease occurs as a complication of influenza, or infectious
pleuropneumonia. The manifestation of pain by moving about in the stall,
refusing to eat and the anxious expression of the face are the first
symptoms that the attendant may notice. The body temperature is higher than
normal, and the pulse rapid and irregular. On auscultation, friction sounds
that correspond to the tumultuous beats of the heart are heard. When fluid
collects within the pericardial sack, the heart beats become feeble and the
pulse weak. Labored breathing and bluish discoloration of the lips follow.
The disease usually runs a very acute course. The prognosis is unfavorable.

_The treatment_ recommended in pneumonia is indicated in this disease.
Absolute rest and the feeding of an easily digested, laxative diet is a
very essential part of the treatment. At the very beginning morphine may be
given to quiet the tumultuous beats of the heart. Cold applications to the
chest wall in the form of ice packs should be used. Heart tonics and
stimulants such as digitalis, strychnine and alcohol should be administered
when the pulse beats weaken. To promote absorption of the exudate, iodide
of sodium may be given. Mustard paste, or a cantharides blister applied
over the region of the heart is useful in easing the pain and overcoming
the inflammation. If fluid collects in sufficient quantity to seriously
interfere with the heart action, the sack may be punctured with the trocar
and cannula and the fluid withdrawn. Great care must be used to avoid
injury to the heart and infection of the part.

[Illustration: FIG. 24.--Elephantiasis in horse.]

ACUTE LYMPHANGITIS.--This is an inflammation of the lymphatic vessels of
one or both hind limbs. The attack comes on suddenly and usually occurs in
connection with rest, and in horses that are of slow, quiet temperament.
The _exciting cause_ is an infection of the part with bacteria, the
infection probably occurring through some abrasion or small wound in the
skin.

_The local symptoms_ are swelling, tenderness and lameness in the affected
limb. The animal may refuse to support its weight on the affected limb. The
lymphatic glands in the region are swollen, and the swelling of the limb
pits on pressure. In the chronic form of the disease, the regions of the
cannon and foot remain permanently enlarged, and the swelling is more firm
than it is in the acute form (Fig. 24).

_The general symptoms_ are high body temperature, rapid pulse and the
partial or complete loss of appetite.

_The following treatment_ is recommended: Exercise is indicated in cases
that are not sufficiently advanced to cause severe lameness, or inability
to use the limb; rest and the application of woollen bandages wrung out of
a hot water solution of liquor cresolis compound are recommended; Epsom
salts in one-half pound doses may be given and repeated in two or three
days; a very light diet of soft feed should be given; liniments should
_not_ be applied until the soreness in the limb has subsided; iodide of
potassium may be given twice daily with the feed.


QUESTIONS

1. What are the functions of the blood and lymph?

2. State the changes occurring in the circulation in inflamed tissue.

3. What is palpitation? Give the causes and treatment.

4. What are the common causes of pericarditis?

5. Give the causes and treatment of acute lymphangitis.



CHAPTER X

DISEASES OF THE NERVOUS SYSTEM


GENERAL DISCUSSION.--The nervous system may be divided into central and
peripheral portions. The _central portion_ comprises the brain or
encephalon and the spinal cord. These organs are lodged in the cranial
cavity and spinal canal. The nerves and ganglia comprise the _peripheral
portion_. The nerves form white cords that are made up of nerve fibres. The
ganglia are grayish enlargements formed by nerve cells and supporting
tissue, situated at the origin of the nerve trunk or along its course.

_The brain_ is an oval mass of nerve tissue elongated from before to
behind, and slightly depressed from above to below. It terminates
posteriorly in the spinal cord. It is divided into three portions:
_cerebrum, isthmus_ and _cerebellum_ (Fig. 25).

_The cerebrum_ forms the anterior portion. It is divided into two lateral
lobes or hemispheres by a deep longitudinal fissure. The surface of the
cerebral hemispheres is gray and roughened by pleats or folds separated by
grooves or fissures. The gray or cortical layer is distinct from the white
or connecting structure. The cortical layer is made up of nerve cells or
areas which control the voluntary muscles of the body. It is connected with
the special senses of touch, temperature and muscle-sense. The gray layer
is connected with the posterior portion of the brain, the isthmus or
medulla oblongata, by the white nerve tissue.

_The isthmus_ or _medulla oblongata_ is elongated from before to behind and
connects the cerebral hemispheres with the spinal cord, anteriorly and
posteriorly. It is divided into several different portions, and is made up
largely of white connecting fibres with nuclei of gray matter scattered
through them. The isthmus is hollowed out by a system of small ventricles
that extend from the cerebral hemispheres to the spinal cord, where they
terminate in a small, central canal. The isthmus is the highway between the
spinal cord and the higher nerve centres. It has in it certain cell centres
that give origin to six of the cranial nerves.

[Illustration: FIG. 25.--Photograph of model of horse's brain: longitudinal
section; lateral view; cerebrum; cerebellum; and isthmus.]

The third division of the brain is the _cerebellum_. This is a single mass
supported by the isthmus. It is situated posterior to the cerebrum, from
which it is separated by a transverse fold of the membranes covering the
brain. This mass of nerve tissue is much smaller than the cerebrum. The
white nerve tissue forms central nuclei which send out branches that ramify
in every direction. The centre of the muscular sense is said to be located
in this division of the brain. A second function is the maintenance of body
equilibrium through its connection with the nerve of the middle ear.

_The spinal cord_ commences at the posterior opening (occipital foramen) of
the cranial cavity, and terminates posteriorly in the lumbar region at the
upper third of that portion of the spinal canal belonging to the sacrum. It
is thick, white in color, irregularly cylindrical in shape, slightly
flattened above and below and reaches its largest diameter in the lower
cervical and lumbar regions. The spinal canal is lined by the outer
membrane that envelops the cord, which aids in fixing this organ to the
wall of the canal. The spinal cord is formed by white and gray nerve
tissue. The gray tissue is situated within the white, and it is arranged in
the form of two lateral comma-shaped columns connected by a narrow
commissure of gray matter. The extremities of the lateral gray columns mark
the origin of the superior and inferior roots of the spinal nerves. The
white tissue of the cord is also divided into lateral portions by superior
and median fissures. The inferior fissure does not extend as far as the
gray commissure, leaving the lateral inferior columns connected by a white
commissure. There are certain centres in the spinal cord that are capable
of carrying on certain reflex actions independent of the chief centre in
the brain. The white matter of the cord is made up of paths over which
impulses to and from the brain are transmitted.

_There are twelve pairs of cranial nerves_. Two pairs belong exclusively to
the special senses, smell and sight. Altogether there are ten pairs that
are devoted to functions connected with the head, either as nerves of the
special senses or in a motor or sensory capacity (Figs. 26 and 27). There
are two pairs distributed to other regions. These are the tenth and
eleventh pairs. The tenth pair or pneumogastric is distributed to the vital
organs lodged within the body cavities.

There are forty-two or forty-three pairs of spinal nerves given off from
the spinal cord. The spinal nerves have two roots, superior and inferior.
The superior is the sensory root and the inferior is the motor root, both
uniting to form a mixed nerve trunk. The sensory root possesses a ganglion
from which it originates.

Generally speaking, the cerebrospinal system deals with the special senses,
movement of skeletal or voluntary muscles and cutaneous and muscular
sensations. In addition to the above there is a distinct system termed the
sympathetic. The _sympathetic system_ consists of a long cord, studded with
ganglia, extending from the base of the neck to the sacrum. The ganglia are
connected with the inferior roots of the spinal nerves. This cord is
connected with groups of ganglia and nerve fibres in the abdominal region,
and this in turn is connected with terminal ganglia in distant tissues.
This system of nerves is distributed to the vital organs of the body.

[Illustration: FIG. 26.--Unilateral facial paralysis caused by injury to
seventh cranial nerve; note position of lip.]

[Illustration: FIG. 27.--Bilateral facial paralysis. This colt was affected
with facial paralysis when born.]

CONGESTION AND ANAEMIA OF THE BRAIN.--In congestion of the brain, the
blood-vessels distributed to the nerve tissue become engorged with blood.
It may be either active or passive.

_The cause of anaemia_ of the brain is an insufficient blood supply. This
may be due to an abundant haemorrhage and cardiac weakness caused by shock
or organic heart disease.

_The causes of congestion_ of the brain are faulty methods of care and
feeding. It sometimes occurs when horses are shipped in poorly ventilated
cars, or kept in close stables. Climatic changes, or changing the stable
and feed, may cause it. Extremely fat animals and animals that are rapidly
putting on fat are predisposed to this disorder. Improper methods of
feeding, lack of exercise, constipation and excitement are the most common
causes. Passive congestion may result from pressure on the jugular vein by
obstructing the flow of blood from the brain, and raising blood pressure in
the blood-vessels of the brain. It is sometimes caused by organic heart
trouble.

_The symptoms_ come on very suddenly in congestion of the brain. The
disease may manifest itself as soon as the animal is moved out of the stall
or bed, or it may come on while it is feeding. In slight cases, the animal
appears excited and restless, the eyes are bright, the pupils are dilated,
and the pulse beats and respirations quickened. If the animal is moving
about, it may stop suddenly and show marked symptoms of a nervous disorder,
such as turning around, running straight ahead and falling down. The period
of excitement is usually brief and may be followed by marked depression.
The mucous membranes of the head are a deep, red color.

_The symptoms_ in anaemic conditions of the brain are loss of
consciousness, stumbling, falling to the ground and sometimes convulsions.
The pig and dog may vomit. Favorable cases return to the normal within a
few hours. Acute inflammatory diseases of the brain and its coverings are
associated with cerebral hyperaemia or congestion.

_The treatment_ of mild cases is to give the animal quiet, well-ventilated
quarters, where it can not injure itself. The animal should be first
subjected to a severe diet and later given easily-digested feed. If it
appears greatly excited, bleeding should be practised. Cold applications to
the head should be used in all cases in the small animals. For internal
treatment, purgatives are indicated. In cases of anaemia, stimulants,
vigorous massage, artificial respiration and injection of physiological
salt solution are indicated.

SUNSTROKE AND HEATSTROKE.--Most writers make no distinction between
heatstroke and sunstroke. The latter is caused by the direct rays of the
sun falling on the animal, and the former from a high temperature and poor
circulation of air in the surroundings. Under such conditions, the physical
condition of the animal and exertion play an important part in the
production of the nervous disturbance.

_The first symptoms_ usually noted are rapid, labored breathing, depression
and an anxious expression on the face. The horse usually stops sweating.
The body temperature is extremely high, the pulse beats weak, the animal
trembles, falls to the ground and dies in a convulsion. Unless measures
directed toward relief of the animal are taken early in the attack, death
commonly occurs. Overheating is rather common in horses that are worked
hard during the extremely warm weather. Horses that have been once
overheated are afterwards unable to stand severe work during the hot months
of the year. Horses in this condition become unthrifty, do not sweat freely
and pant if the work is hard and the weather is warm.

_The preventive measures_ consist in not exposing animals that are fat, or
out of condition to severe exercise if the day is close and hot, especially
if they are not accustomed to it. When handling or working animals during
hot weather all possible precautions to prevent overheating should be
practised.

_The treatment_ consists in placing the animal in a cool, shady place and
fomenting the body with cold water. The cold packs or cold fomentations
should be applied to the head and forepart of the body only. Small doses of
stimulants may be given.

MENINGO-CEREBRITIS.--The discussion of inflammation of the brain and its
coverings can be combined conveniently, as the causes, symptoms and
treatment vary but little. This disorder is met with in all species of
domestic animals, but it is most common in horses and mules. Some writers
state that meningo-cerebritis is more common during the warm season than it
is in the winter. However, this does not hold true in all sections. In the
middle west, this disease is more common in late fall and winter.

_It is commonly caused_ by taking into the body with the feed and water
certain organisms and toxins that are capable of producing an inflammation
of the brain. The infectious organism or toxins are taken up by the
absorbing vessels of the intestines.

The secondary form of the disease usually occurs in connection with other
diseases such as influenza, tuberculosis and acute pharyngitis, or as a
result of wound infection. Unhygienic conditions, as unsanitary and poorly
ventilated stables and filthy drinking places, play a very important part
in the production of the simple or acute form of meningitis.

Sudden changes in the feed and the feeding of rotten, mouldy feeds may
cause it. In the fall and winter it may follow the feeding of too heavy a
ration of shredded fodder or any other dry feed. Other exciting causes are
overexertion, changes in climate, excitement, injuries to the head and the
feeding of too heavy and concentrated a ration.

_The symptoms_ vary in the different individuals, but in general they are
the same. At first the animal is dull, or extremely nervous and sensitive
to sounds. The pupils of the eye are unevenly contracted at first, later
dilated. The eyes may appear staring, or they are rolled about, so that the
white portion is prominent. The unusual excitement is manifested in
different ways by the different species. During the dull period the animal
is indifferent to its surroundings. When it is excited, the pulse beats and
respirations are accelerated. The body temperature is often elevated early
in the disease. There is a partial or complete loss of appetite. Paralysis
may be the most prominent symptom. The animal lies in a natural position,
or stretched out and lifting the head occasionally and moving the limbs,
but it is unable to rise. Loss of sensibility may gradually progress until
the animal becomes semiconscious, or comatose.

In case the inflammation is acute and involves the greater portion of the
brain and its coverings, death occurs within a few days. Occasionally the
animal survives several weeks. There are few permanent or complete
recoveries.

_The principal lines of treatment_ are preventive measures and careful
nursing. This is one of the diseases that can be largely prevented by
observing all possible sanitary precautions in caring for animals. It is
admitted by writers that the greater majority of cases of inflammation of
the brain and its coverings are caused by infection. Proper stable
construction, ventilation and disposal of the manure, an occasional
disinfection of the stable, cleaning and disinfecting the drinking places
and water tanks, and the necessary attention to the ration greatly reduce
the loss from this disease.

The animal should be gotten into a dark, quiet, roomy stall that is well
bedded. A swing may be placed under a large animal if it is able to support
any of its weight, and there is no evidence of nervous excitement. We
should do nothing to disturb it. If possible, the position of the animal
that is unable to get up should be changed, and the bed kept clean and dry.
Cold in the form of wet or ice packs should be applied to the head during
the acute stage. Symptoms of excitement must be overcome by large doses of
sedatives. Iodide of potassium and strychnine may help in overcoming the
paralysis. The bowels should be emptied by giving an occasional physic. A
very light, easily digested diet should be fed.

PARTIAL OR COMPLETE PARALYSIS OF THE POSTERIOR PORTION OF THE BODY.--This
disorder is especially common in the small animals. The hog is most
frequently affected.

_The following causes_ may be mentioned: Inflammation of the spinal cord
commonly occurs in influenza, strangles and mixed infections; constipation
brought on by improper feeding and insufficient exercise is a predisposing
cause; injuries such as strains and blows in the region of the back may
also cause it; compression of the spinal cord by the vertebrae is no doubt
a very common cause; dislocation, enlargement of the disks between the
vertebrae, bony enlargements resulting from strains and injuries, rickets,
tuberculosis and actinomycosis and tumors commonly cause compression of the
cord. It is rarely caused by parasites. Young, fat animals are especially
prone to injuries in the region of the back. Such animals may suffer from
malnutrition of the bones, and complete fractures of the thigh bones may
occur. Extreme heat from the sun's rays and close, hot quarters are
probable causes.

_The symptom_ that is most prominent is the partial or complete loss of
control over the movements of the hind parts. The appetite may be little
interfered with. The animal may sit on the haunches, with the limbs
projecting forward, or swing the hind quarters from side to side in walking
or trotting. Irregularity in the animal's movements is especially
noticeable when turning or backing. In case the animal suffers pain, the
spine is held rigid or arched, and when forced to move, marked evidence of
pain occurs. There may be a decrease or increase in the sensibility of the
part. The increase in sensibility is noticed on striking the muscles with
the hand or rubbing the hair the wrong way. Spasmodic twitching or
contractions in the muscles sometimes occur. There is frequent elevation of
temperature. The animal is unable to pass urine or faeces, or there may be
an involuntary passage of the body excretions.

The outcome of this disease is unfavorable. Acute inflammation of the
covering of the cord may subside within a few days. Cases that do not
recover within a few weeks should be destroyed. Paralysis of the hind parts
should not be confused with rheumatism, azoturia and other disorders that
may interfere with the movements of the posterior portion of the body.

_The treatment_ is largely along preventive lines. A predisposition toward
rickets, and injuries, may be prevented by feeding a proper ration, and
permitting the animal to take exercise. The quarters and the attendant are
frequently responsible for injuries. If this is the case, the rough
handling of the animals should be immediately corrected, and any condition
of the quarters that favors the crowding or piling up of animals should be
changed. Large animals may be placed in swings if they are able to support
a part of their weight on the hind limbs. This is especially indicated at
the very beginning of the disorder. Small animals should be given a good
bed. A very light, easily digested ration should be fed. An occasional
physic should be administered. Strychnine and iodide of potassium may be
given. Cold applications to the back are indicated.


QUESTIONS

1. What organs comprise the central portion of the nervous system?
   Peripheral portion?

2. Give a general description of the brain.

3. Give a general description of the spinal cord.

4. What is the sympathetic system?

5. Describe the causes and symptoms of congestion of the brain.

6. What is heatstroke? Give the treatment.

7. Give the preventive and curative treatment of inflammation of the brain.

8. State the causes, and give the proper treatment of paralysis of the
   posterior portion of the body.



CHAPTER XI

DISEASES OF THE SKIN


GENERAL DISCUSSION.--The two layers that form the skin are the _epidermis_
and the _derma_. The cells of the outer layer or epidermis are of two
kinds. The superficial portion is formed by horny, flattened cells and the
deeper by softer cells. This layer of the skin varies greatly in thickness
in the different species. The derma is composed of some muscular fibres
interwoven with the connective-tissue fibres. It contains the roots of the
hair follicles, sweat and oil glands. The external face which is covered by
the epidermis shows a multitude of little elevations. These are the
vascular and nervous papillae. In addition, it shows openings through which
the hairs and the skin glands pass. The inner surface is united more or
less closely to the muscular or underlying tissue by a layer of fibro-fatty
tissue.

_The appendages of the skin_ are the hairs and horny productions. The horny
productions comprise the horns, chestnuts, ergots, claws and hoofs.

_The hair varies_ in length, thickness and coarseness in the different
species, and the different regions of the body. In addition, breeding,
care, heat and cold may cause marked variations in the thickness of the
coat. Exposure to cold causes the coat to thicken. High temperatures cause
the short hairs to drop out and the coat to become thin.

Diseases of the skin may be _classified as parasitic_ and _non-parasitic_.
Parasitic skin diseases are caused by animal and vegetable parasites.
Non-parasitic skin diseases are caused by irritation to the skin and
internal causes. Irritation to the skin may be either chemical, thermic or
mechanical. The internal causes may be due to an individual predisposition
together with digestive disturbances and the eating of feeds too rich in
protein. In this chapter parasitic skin diseases produced by insects will
not be discussed.

FALLING OUT OF THE HAIR AND FEATHERS.--Falling out of the hair and feathers
frequently occurs independent of parasitic diseases. This condition does
not occur as an independent disorder, but as a secondary affection. It is
due to faulty nutrition, and irritation to the skin. Intestinal diseases,
insufficient feed and feed of bad quality are common causes. Animals that
are fed a heavy ration, or that lie on dirty, wet bedding frequently lose
large patches of hair. Sheep that are dipped in late fall and early winter,
or exposed to wet, cold weather may lose a part of their fleece. It is not
uncommon for animals toward the latter period of pregnancy, or that sweat
freely, to lose patches of hair.

Falling out of the hair heals of itself within a few weeks.

_The preventive measures_ are of special importance in sheep and horses.
This consists in avoiding conditions that may lead to alopecia and in
correcting the diet. In horses the regions of the mane and tail should be
washed with soap, or rubbed with alcohol and spirits of camphor, equal
parts. Treatment should be persisted in for a long period if necessary.

URTICARIA, "NETTLERASH."--Urticaria is characterized by roundish elevations
that appear quickly and become scattered over a part or the whole surface
of the skin. They are caused by an inflammatory infiltration of the deeper
layers of the skin. Horses and hogs are most frequently affected.

_The causes_ of urticaria are irritating juices of certain plants,
secretions of flies, ants and some caterpillars, irritating drugs,
scratching, sweating and the action of cold on a warm skin. It has been
observed in connection with the feeding of certain leguminous feeds and
digestive disturbances. Horses that are fat, or putting on flesh rapidly,
seem to be predisposed to this disorder. Urticaria may occur in certain
infectious diseases.

_The characteristic symptom_ is the formation on the skin of roundish
elevations or "hives." There may be an elevation of body temperature and
partial loss of appetite. Small animals may act restless and show evidence
of itching or pain. This symptom is very common in hogs. The eruption may
last only a few hours or a few days, or, because of the animal's scratching
or rubbing the part, the skin may become scabby and small pustules form.

An important _preventive measure_ is to avoid the use of agents capable of
irritating the skin and producing urticaria when treating parasitic skin
diseases. It is very advisable to give the animal a saline cathartic (Epsom
or Glauber's salts). The skin may be washed with cold water, or a weak
water solution of permanganate of potassium.

ACNE, "SUMMER RASH."--In this skin disease the oil glands and hair
follicles are inflamed and sometimes infected with pus germs. This results
in skin eruptions varying in size from the point of a pin to about a
quarter of an inch in diameter. This inflammation is most prominent during
the warm weather.

_The causes_ are local irritation to the skin from lying on filthy floors,
sweating and irritation from the harness. According to some writers, pus
germs are the only cause, the mechanical agents merely aiding in the
production of the infection.

The face, side of the neck, shoulders, back and sides of the trunk and
quarters are the usual seats of disease. The pimples or nodules may
disappear within a few weeks, or persist throughout the warm season. The
eruption may disappear without leaving scars, or suppuration occurs and
small bald spots result.

_The treatment_ consists in removing the cause of the disease and cleaning
the skin with antiseptic washes. The surroundings of the animal must be
kept clean and a good bed provided. If possible, the horse should be laid
off from work as soon as the condition is noted. Washing the part with a
weak water solution of permanganate of potassium may be practised daily.
Fowler's solution of arsenic may be given. This may be given with the feed.

ECZEMA.--This is an inflammation of the vascular capillary bodies and the
superficial layer of the skin. There may be marked inflammatory exudate,
causing the surface of the skin to become excessively moist and more or
less itching. Redness, vesicles and pustules may characterize the
inflammation. In the chronic form the skin may become thickened and greatly
changed in structure.

Eczematous inflammation of the skin may occur in all domestic animals, but
it is most common in the dog. In the horse local eczema (scratches) is
common.

The most frequent _cause_ is external irritation. Accumulations of filth on
the skin and continual wetting of the part are common causes. Mechanical
causes are rubbing, pressure, the action of the sun's rays and chemical
irritants. Internal causes, such as catarrhal diseases of the stomach and
weakness and emaciation from disease, may act as direct or predisposing
causes. Tender-skinned animals seem to be predisposed to the disease.

_The symptoms_ vary in the different species of animals. In the horse the
thin skin posterior to the fetlock and knee, in front of the hock and on
the under side of the body is most commonly inflamed. Moisture and dirt
seem to be the most common causes. Eczema may involve the skin covered by
the mane and tail in animals that are not properly groomed and inclined to
rub or scratch. Cattle may suffer from eczematous inflammations in the
region of the forehead, back of neck and base of tail. A very common form
of the disease involves the space between the toes. Sheep frequently suffer
from inflammation of the skin over the fetlock region. The skin of animals
having long fleeces, or heavy coats of hair that become wet at a time when
there is no opportunity to dry out quickly, may become inflamed. Dogs are
commonly affected by the acute and chronic forms of eczema. Eczema of swine
is limited mostly to young hogs. It is rather rare, excepting in hogs that
are pasturing on certain kinds of clover and rape, or on muck lands.

The inflammation is accompanied by a marked tenderness and itching, and the
animal licks and scratches the part. This increases the extent of the skin
lesions. The skin appears moist, later dirty, scabby and thickened. Cracks
and pustules may form. Gangrene and sloughing of the skin may occur.

_The treatment_ is both preventive and curative. Cases of eczema caused by
filth and wetness can be prevented by giving the necessary attention to
keeping the skin clean and not allowing animals access to muddy, filthy
places. Keeping the bed clean and regulating the diet are important
preventive measures. Before the inflammation can be successfully treated
the cause must be removed.

In acute eczema it is advisable to protect the part against water, filth
and air. Powders and ointments may be used during the early stages of the
inflammation. Two parts boric acid, four parts flour, and one part tannic
acid may be dusted over the moist surface. One part zinc oxide and twelve
parts vaseline is a useful ointment. Scratching the part should be
controlled in every case by muzzles, collars and bandages. Dirt and scales
may be removed from the skin by washing with cotton soaked in lime water or
linseed oil. The animal should receive laxative doses of Glauber's salts or
oil every few days. A simple, easily digested ration should be fed. The
following mixture may be applied in obstinate cases: oil of tar and soft
soap, two parts each, and alcohol one part.

COMMON FEED RASHES.--This title includes inflammation of the skin caused by
pasturing on buckwheat, certain clovers and rape, together with moisture
and sunlight.

Green, flowering buckwheat is more dangerous as a feed for stock than is
the grain or straw. Clovers and rape are not as dangerous a feed. The
actual cause of the skin becoming inflamed is not known.

The skin in the regions of the face, ears, neck, lower surface of the body
and limbs becomes red and covered with vesicles. Later, scabs and pus may
form.

_The treatment_ consists in changing the ration and keeping the animals out
of the sun, or long grass and weeds for a few days. This is all the
treatment required in most cases. It may be advisable to administer a
physic. If pus and scabs form, the part should be cleansed daily with a one
per cent water solution of permanganate of potassium.

HERPES (FUNGOUS SKIN DISEASE).--This is a contagious disease of the skin
caused by thread fungi, _Tricophyton tonsurans_ and _epilans_, which
develop in the skin in localized areas, causing vesicles, scabs or scales
to appear, and the loss of the hair over the part. This skin disease occurs
in all domestic animals, but it is most commonly met with in cattle. It
usually affects young cattle. It most commonly occurs in the region of the
face and neck. Thick, bran-like crusts form over the scattered areas of the
skin and the hair drops out or breaks off. The animals frequently rub the
infected area.

_Prompt treatment_ may prevent the spread of this disease in the herd. It
may be checked by quarantining the infected animals and scrubbing the
stalls, stanchions and walls with a disinfecting solution. Grooming the
infected animal should be discontinued. This skin disease responds most
readily to ointments. Flowers of sulfur one part and lard ten parts is
commonly used by stockmen. Sulfur-iodide ointment, or tincture of iodine
may be applied.


QUESTIONS

1. Give a general description of the skin.

2. Give the causes and treatment of falling of the hair.

3. What is urticaria? Give the treatment.

4. What is summer rash? Give the treatment.

5. What is "scratches"? Give the treatment.

6. What feeds produce rashes of the skin?

7. What fungus produces an inflammation of the skin in cattle? Give the
   treatment.



CHAPTER XII

DISEASES OF THE EYE


GENERAL DISCUSSION.--_The eye_ is situated in the orbital cavity, to which
it is attached by muscles that rotate it in different directions. The
_orbit_ is lined by fibro-fatty tissues that form a cushion for the eye.
Anteriorly it is protected by the _eyelids_, and in birds by a third eyelid
that corresponds to the membrana nictitans of quadrupeds. The _lachrymal
gland_ which secretes the tears keeps the above parts moist.

_The eye_ is the essential organ of vision. It is formed by a spherical
shell which encloses fluid or semisolid parts. The shell is anteriorly made
up of a transparent convex membrane, the cornea, while the remainder of its
wall is formed by three opaque layers or tunics.

The external tunic is the _sclerotic_. It is a white, solid membrane,
forming about four-fifths of the external shell. Its external face is
related to the muscles and fatty cushion. It receives posteriorly, a little
lower than its middle portion, the insertion of the _optic nerve_, which
passes through the shell and spreads out to form a very thin membrane, the
retina or internal coat.

_The retina_ lines about two-thirds of the posterior portion of the shell
of the eye. It is made up of seven layers. The essential layer is named
from its appearance, rods and cones.

The middle coat is the _choroid_. This is a dark, pigmented, vascular and
muscular membrane. The posterior portion is in contact with the retina.
Anteriorly it forms the ciliary processes and the iris.

_The media_ of the eye are the crystalline lens, vitreous and aqueous
humors. The _crystalline lens_ is a transparent, biconvex body sustained by
the ciliary processes. The _vitreous humor_ is a transparent jelly-like
substance that fills all the cavity of the eye posterior to the lens. The
_aqueous humor_ is a liquid, contained in the anterior and posterior
chambers of the eye in front of the lens. This fluid separates the iris
from the front of the lens.

EXAMINATION OF THE EYE.--In examining and treating the eye we should avoid
rough and hasty manipulation. The animal should be approached slowly. It is
best for the attendant who is familiar with the animal to hold it for the
examiner. It is advisable on approaching the animal to stroke its face, and
in the horse to brush its foretop away. The hand should be carried slowly
to the front of the eye, and the lids separated with the fingers and thumb
if we wish to obtain a better view of the cornea. In cattle the best view
of these parts can be obtained by taking hold of the nose and lifting the
head. It is impossible to make a satisfactory examination of the eye
outside of the stable where the light is coming from all directions. The
most satisfactory conditions under which a general examination can be made
is to stand the animal facing a transom, window or open door. We may then
look directly into the eye and note the condition of the different
refracting media.

The lens should appear transparent and free from scars. The aqueous humor
free from any cloudiness or precipitate. Both pupillary openings should be
the same size, and not too small or too large in the bright light. As we
look through the pupillary openings, both the lens and the vitreous humor
should refract the light properly and not appear white or greenish-white in
color. The color of the iris should be noted. If it lacks lustre or appears
dull, this may indicate an inflammation. In periodic ophthalmia in horses
the iris loses its lustre and becomes a rusty-brown color. It is very
important to note this change in the appearance of the iris. We should
note, in addition, the expression of the animal's face, the position of the
ears and eyelids and manner of the walk. Horses that have defective sight
may show a deep wrinkle in the upper eyelid when startled or looking
directly at an object. Animals that are blind hold the ears in a
characteristic position, and may stumble and walk over, or run into objects
unless stopped. The ophthalmoscope is a very useful instrument for
determining the condition of the different structures of the eyes, when in
the hands of persons who are trained in its use.

CONJUNCTIVITIS.--This is an inflammation of the mucous membrane lining the
eyelids and covering the eyeball. The two forms of conjunctivitis common in
domestic animals are the _catarrhal_ and _purulent_.

_The symptoms differ_ in the two forms of conjunctivitis. They may be
distinguished from each other by the difference in the character of the
inflammatory discharge. In the catarrhal form, there is a discharge of
tears and the lids are held more or less closed. The mucous membrane is
usually brick red in color and swollen. A little later the discharge
becomes heavier and adheres more to the margins of the lids. The lids
continue tender and the inflammation painful. The surface of the cornea may
appear white and the blood-vessels prominent, but it is only in the severe
cases that inflammation of this portion of the eye occurs. In such cases an
elevation in body temperature may occur. This is especially true of
purulent conjunctivitis when primarily caused by an infectious agent. In
the purulent form the discharge is heavy and pus-like.

_The treatment_ is both preventive and curative. The first object must be
to remove the cause. Irritating gases resulting from stable filth should be
remedied by correcting the unsanitary conditions in the stable. Conditions
favoring injury to the eye from foreign bodies, such as chaff and a
careless attendant, should be corrected. Animals suffering from the
infectious or purulent form of inflammation should be separated from the
other animals. Foreign bodies should be removed promptly before they have
had an opportunity to set up a serious inflammation. It is necessary to
confine the animal in some way before attempting to do this. Horses should
be twitched, cattle held by the nose, and the head of a small animal held
firmly with the hands. It may be necessary to cocainize the eye before the
operator can remove the foreign object with absorbent cotton or with
forceps.

In case of injuries and irritation to the lids by foreign bodies, the eye
may be flooded with a three per cent water solution of boric acid twice
daily, or as often as necessary. Such washes or lotions may be applied with
a small piece of absorbent cotton, using a fresh piece each time the eye is
dressed. A medicine dropper may also be used. A lotion containing silver
nitrate two to four grains and distilled water one ounce, is useful in
combating the inflammation. This may be applied twice daily. Irritating
lotions should be avoided, if possible, in the treatment of eye diseases of
horses, because of the danger of making the animal disagreeable to handle.
Boric acid may be dusted over the ball of the eye of cattle with a powder
blower.

PERIODIC OPHTHALMIA, "MOONBLINDNESS."--This is a periodic inflammation of
one or both eyes of the horse. The internal structures of the eye are
involved by the inflammation, but it may appear as a conjunctivitis.

_The cause_ of this disease is not well understood. Certain local
conditions seem to favor its development. Undrained land, a humid climate,
the feeding of a one-sided ration or one that does not maintain the
vitality of the animal, and severe work seem to produce it. Heredity must
be accepted as a prominent accessory cause. A number of different bacteria
have been mentioned as causative factors for this disease.

_The symptoms_ at the very beginning indicate a general inflammation of the
eye. The eyelids are swollen, there is an abundant secretion of tears, the
eyeball is retracted and the lids are held more or less closed. As the
inflammation progresses, the cornea becomes milky in appearance and the
aqueous humor may show a precipitate toward the bottom of the anterior
chamber. The pupil is usually contracted and dilates slowly when the animal
is moved into the light. The acute inflammation gradually subsides, and
about the tenth to the fourteenth day the lids and cornea may appear
normal.

The periods between these acute attacks of ophthalmia may vary from a few
weeks to several months. Severe work, debility and the character of the
ration influence their frequency. It is not uncommon for animals that have
been given a rest to suffer from a second attack on being put to work. The
attendant may observe a hazy or whitish condition of the margin of the
cornea. The upper lid may show an abrupt bend of its margin and a deep
wrinkle. The color of the iris appears to have lost its lustre, and the
aqueous humor and lens may be cloudy. After a variable number of attacks
glaucoma or cataract develops.

_The history_ of the case will enable the attendant to recognize this form
of ophthalmia.

_Treatment_ is unsatisfactory. Preventive measures consist in avoiding
conditions favorable to the production of the disease. This should be
practised so far as possible. At the time the attack occurs, the animal
should be given a cathartic. One pound of Glauber's salts in a drench is to
be preferred. Rest in a darkened stall is indicated. An eye lotion
containing three grains of silver nitrate in one ounce of distilled water
should be applied to the eye three times daily. A water solution of
atropine or eserine should be used for the purpose of relieving the
symptoms of iritis or glaucoma. A very light diet should be fed.

INFECTIOUS OPHTHALMIA OF RUMINANTS.--This occurs as an acute inflammation
of the eyelids and cornea. The disease is highly infectious, affecting all
of the susceptible animals in the herd. It commonly occurs during the late
summer and fall.

_The symptoms appear_ suddenly. The animal is feverish, the eyes closed and
the cheeks are wet with tears. The cornea becomes clouded, white and
opaque. In severe cases, the blood-vessels around the margin of the cornea
become prominent, and ulcers form on its surface. The animal's appetite is
impaired or lost. There is loss of flesh and temporary blindness. The
blindness in one or both eyes may persist for a period of from two weeks to
several months. Permanent blindness is comparatively rare.

_The preventive treatment_ consists in practising the necessary precautions
against the introduction of the disease into the herd, and in carefully
quarantining the first cases of the disease that appear. The affected
animal should be given a darkened stall, and fed a very light ration until
the acute inflammation has subsided. From one to one and one-half pounds of
Glauber's salts should be given. The _local treatment_ consists in the
application of antiseptic lotions or powders to the eye. Equal parts of
boric acid and calomel, dusted into the eye twice daily with a powder
blower, is a very effective treatment.


QUESTIONS

1. Name the different structures that form the shell of the eye; name and
   describe the different media of the eye.

2. Give the general method of examining the eyes of horses.

3. What is conjunctivitis? Give causes and treatment.

4. What is "moonblindness"? Give the symptoms.

5. Describe the symptoms of infectious ophthalmia of ruminants and the
   treatment.



CHAPTER XIII

GENERAL DISEASES OF THE LOCOMOTORY APPARATUS


GENERAL DISCUSSION.--The movements of the different parts of the animal
body depend on the union of the bones that form the skeleton (Fig. 28), and
mode of insertion of the muscles. The bones meet and form _joints_ or
_articulations_. These are divided into three classes: _movable_, _mixed_
and _immovable_. Nearly all of the articulations in the extremities belong
to the movable class. The articulations between the bodies of the vertebrae
belong to the mixed, and those between the flat bones of the head to the
immovable class.

[Illustration: FIG. 28.--Skeleton of horse.]

The bony surfaces that meet and form the different types of articulations
are held together by ligaments (Fig. 29). Sometimes the ligament is placed
between the bony surfaces, but usually it is attached to the margins of the
articular surfaces that it unites. The _immovable class_ possesses
fibrous-like ligaments that are placed between the margins of the flat
bones that form the articulation. The _mixed articulations_ are united by a
fibro-cartilaginous pad that is firmly attached to the articular faces of
the bones, and by peripheral ligaments that may be flat or formed by
scattered fibres. All _movable articulations_ are formed by bony surfaces
encrusted with a thin cartilaginous layer that makes them perfectly smooth,
ligaments and complimentary cartilages. Sometimes the bony surfaces do not
fit each other, and we find between them _fibro-cartilages_ that complete
the articulation by adapting the articular surfaces to each other. _Round_
or _flat ligaments_ may extend from one articular surface to the other, and
attached to the margins of the articulation are _membranous, flat_ or
_round ligaments_. Muscles and tendons that cross the articulations should
be included among the structures binding them together.

[Illustration: FIG. 29.--Photograph of model of stifle joint, showing:
ligaments; complementary cartilages; femur; and tibia.]

Movable joints possess a _synovial membrane_. This membrane lines the
structures that enclose the articulation and secretes a fluid, _the
synovia_, that lubricates the surfaces.

_The muscles_ are the contractile organs that move the body. The movement
of the different parts of the body is rendered possible through the manner
in which the skeletal muscles are inserted into the long bones, by which
the lever motion is possible. A muscle originating on one bone and
terminating on another either moves both bones toward each other or, if one
attachment is fixed, the movable is drawn toward the fixed part.

We may class muscles as _striated_ or _voluntary_ and _unstriated_ or
_involuntary._ A third class, _mixed,_ is represented by the heart muscle.
The striated is represented by the skeletal muscles, and the unstriated by
the thin muscular layers that form part of the wall of the stomach,
intestines, bladder and other hollow organs.

RHEUMATISM.--This is an inflammation of the tissues that form the
locomotory apparatus. The effect of cold on the muscles and tendons is an
important factor in its production. It differs from other inflammations by
shifting from one part to another. It is termed _muscular rheumatism_ when
it affects the muscles, tendons and fascia, and _articular rheumatism_ when
it involves the articulations. A second classification, _acute_ and
_chronic,_ depends on the character of the inflammation. The muscular form
is common in horses, dogs and hogs, while the articular form more commonly
affects cattle.

_The following causes_ may be considered. Animals that are exposed to cold,
wet, changeable weather, or kept in cold, damp, draughty quarters
frequently suffer from rheumatism. Under such conditions it is very
probable that imperfect metabolism of body tissue occurs, and certain toxic
products that are capable of irritating the muscles and articulations form.
Clinical symptoms, and the presence of bacteria in the inflamed tissue
indicate that bacteria and their toxins play an important part in the
development of articular rheumatism. Heredity is said to be an important
predisposing factor. One attack always predisposes the animal to a second.

_The symptoms vary_ according to the severity of the attack. Local
rheumatism is not accompanied by serious symptoms. The regions most
commonly involved in local, muscular rheumatism are the shoulder, neck and
back. The joints affected in the articular form are the knee, fetlock, hip,
elbow and shoulder. The attack is usually sudden and accompanied by fever,
more or less loss of appetite and soreness. Loss of control over the
movement of the hind parts or walking on the knees may occur in the smaller
animals. The larger animals show a slight or severe lameness. The affected
muscle or articulation may be swollen, hot and tender. Pressing on the part
with the hand or forcing the animal to move about may cause severe pain.
Weakness and emaciation may occur in generalized and articular rheumatism,
especially if suppuration takes place in the affected joint.

_The prognosis_ is more favorable in muscular rheumatism than in the
articular form. Both forms may become chronic. It is frequently advisable
to destroy animals suffering from the articular form because of their
emaciated, weakened condition and the deformed condition of the joints.

_The preventive treatment_ consists in avoiding conditions favorable to the
production of rheumatism. In ventilating the stable we should avoid
draughts. Practical experience indicates that allowing a horse to stand in
a draught after it has been warmed up by exercise is a very common source
of muscular rheumatism and is especially to be avoided. Young hogs and sows
that are thin are very prone to rheumatism when given wet, draughty
sleeping quarters. Houses having dirt or loose board floors are very often
draughty. Concrete floors when wet and not properly bedded with straw are
objectionable. Although we do not fully understand the causative factors,
we can take advantage of the knowledge we have gained from practical
experience, and avoid keeping animals under conditions that are favorable
for the production of the disease. It is almost useless to treat rheumatism
unless the conditions under which it occurred are corrected.

_The treatment_ is both local and internal. The local treatment consists in
applying a mild liniment to the part, together with massage. If the part is
tender and painful, hot applications may be used. Spirits of camphor ten
parts and turpentine two parts, applied daily, are useful in relieving the
soreness of rheumatic muscles. Salicylate of soda two ounces, fluid extract
of gentian one ounce, and sufficient water to make an eight-ounce mixture
may be given internally three times daily after feeding. Of the above
mixture horses and cattle may be given one-half ounce and sheep and swine
from one to two drachms. The treatment should be continued for a period of
from eight to ten days or longer. It may be repeated in from one to two
weeks.

[Illustration: FIG. 30.--Atrophy of the muscles of the thigh resulting from
an attack of azoturia.]

Iodide of potassium is very useful in the treatment of chronic articular
rheumatism. A very light diet should be fed and the animal given as
complete rest as possible. An occasional physic should be given.

AZOTURIA, HAEMOGLOBINURIA.--This is a disease of solipeds affecting the
muscles of the quarters. The affected muscles become swollen, hard and
paralyzed. The disease follows a short rest, and rarely occurs when the
animal is running in pasture or idle for a long period. Animals that are
fat or rapidly putting on fat are predisposed to it. Animals that have had
one attack are predisposed to a second.

_The cause_ of this disease is not positively known. The German
veterinarians attribute it to irritation of the muscles by cold, and
classify azoturia as a rheumatic disorder. The conditions preceding the
attack are not in favor of this theory, and cold can not be considered an
important causative factor. The most acceptable is the auto-poisoning
theory advanced by Dr. Law.

Azoturia is common in the country where feed is abundant and wrong methods
of feeding horses are commonly practised. It is a very common practice to
feed horses accustomed to hard work the same ration when idle for a few
days as when working. The blood of horses cared for in this way may become
abnormally rich in albuminoids. The suddenness of the attack, occurring
shortly after the animal is given exercise, indicates auto-poisoning. This
may be due to the blood in the portal vessels and the liver capillaries,
charged with nutritious and waste products from the overfed animal's
intestines, being suddenly thrown into the general circulation by a more
active circulation of the blood brought on by exercise.

_The symptoms_ of disease are manifested shortly after the animal is moved
out of the stall and given exercise. When the animal is first exercised it
is usually in high spirits. After travelling a short distance it is noticed
to sweat more freely than ordinarily, breathe rapidly, lag and go lame,
usually in the hind limbs. It trembles, shows evidence of suffering severe
pain by turning its head and looking around toward the flanks, knuckles
over in the hind pasterns, and may fall down and be unable to get up. The
affected muscles appear to be swollen and feel unusually firm when pressed
upon with the hand. If the horse does not go down recovery may occur within
a few hours, and we are able to move the horse to the stable. Dark brown
urine may be passed. At other times, the animal lies in a natural position,
possesses a good appetite, but can not stand. In the severe form, it is
restless and shows marked nervous symptoms.

_The prognosis_ is unfavorable in the severe form. When nervous symptoms
are absent recovery usually occurs in from two to ten days. Complications
are common. More or less atrophy of the muscles of the quarters may result
(Fig. 30).

_The preventive treatment_ consists in avoiding conditions that may favor
the production of the disease. More attention should be given the feeding
and care of work animals. If it is not possible to permit horses that are
worked to exercise in a lot or pasture when idle, the ration should be
reduced and roots, chopped, or soft feed given.

Careful nursing is an important part of the _treatment_. As soon as the
horse shows evidence of an attack, it should be stopped and allowed to
stand until sufficiently recovered to be moved. If paralysis occurs, we
should make it as comfortable as possible and arrange to move it to a
comfortable, warm, well-bedded stall. It may be advisable to place the
animal in slings. This is not advisable in the serious form of the disease
because of the extent of the paralysis and the nervous symptoms. A very
light diet, bran mashes, chopped hay or green feed, should be fed during
the convalescent period and for several days after complete recovery has
occurred.

The following lines of _medicinal treatment_ may be recommended. We should
endeavor to stimulate the elimination of the waste products from the body
by way of the kidneys, intestines and skin. This may be accomplished by
administering saline cathartics, covering the body with blankets,
encouraging the animal to drink plenty of water and feeding soft feeds.
Glauber's salts may be given as a drench, or eserine may be given
hypodermically. Sedatives such as chloral hydrate may be used to quiet the
animal.


QUESTIONS

1. Give a general description of the locomotory apparatus.

2. Give the causes of rheumatism; describe the treatment.

3. What is azoturia? Give the cause of this disease.



CHAPTER XIV

STRUCTURE OF THE LIMBS OF THE HORSE


GENERAL DISCUSSION.--Each limb is formed by a column of bones that rest
upon one another, forming more or less open angles. The bones of the column
meet and form articulations that are held together by ligaments, and
attached to their faces, borders and extremities are muscles and tendons.
In the superior portion of the limb the muscles are heavy, tapering
inferiorly, and terminating in the region of the foot in long tendons. Each
limb is divided into four regions. The regions of the _fore-limb_ are the
shoulder, arm, forearm and forefoot. In the _hind limb_ are the regions of
the pelvis, haunch, thigh, leg and hind-foot. The feet in turn are divided
into three sub-regions each. The _forefoot_ is formed by the knee, cannon
and toe, and the _hindfoot_ by the hock, cannon and toe.

THE SHOULDER BONE OR SCAPULA is flat and triangular in shape. It is
attached to the trunk by heavy muscles, one of which, together with its
fellow on the opposite side, may be compared to a great, muscular sling
that supports about two-thirds of the body weight. Attached to the internal
and external faces of the scapula are heavy muscles that pass over the
shoulder-joint, and become attached to the arm bone through the insertion
of their muscular fibres or by a short tendon.

THE ARMBONE OR HUMERUS belongs to the class of long bones. Its superior
extremity forms a flattened head that fits rather imperfectly into a
shallow cavity in the humeral angle of the scapula. The inferior extremity
resembles a portion of a cylinder in shape, and fits into shallow
depressions in the superior extremity of the principal bone of the forearm.
The muscles here are divided into two regions, anterior and posterior
brachial. The most of these muscles originate on the posterior border and
inferior extremity of the shoulder bone, and terminate inferiorly on the
superior extremities of the principal and second or rudimentary bone of the
forearm. The posterior brachial muscles are heavy and powerful. They are
sometimes termed elbow muscles, because they are attached to the point of
the elbow.

THE REGION OF THE FOREARM is formed by two bones, the _radius_ and _ulna_.
The radius is the principal bone and is classed among the long bones. The
ulna is an elongated flat bone. It is attached to the external portion of
the posterior face of the radius and extends above the superior extremity
of this bone to form the point of the elbow. The radius articulates with
the upper row of knee bones. The muscles of this region, the antibrachial,
are divided into two sub-regions, anterior and posterior. They originate
superiorly from the lower extremity of the arm bone and the superior
extremities of the bones of the forearm, and terminate toward the lower
extremity of the region in tendons that become attached to the bones of the
knee, cannon and digit.

THE KNEE OR CARPAL region is formed by seven short bones that are arranged
in two rows. They form a series of articulations. These are the
articulations between the two rows, between the bones of each row, and
between the upper and lower rows and the neighboring regions. Nearly all
the motion takes place in the articulation between the upper row and the
principal bone of the forearm.

THE CANNON OR METACARPAL region is formed by three bones. These are the
principal metacarpal or cannon bone, and the rudimentary metacarpal or
splint bones. The latter are attached to the margins of the posterior face
of the cannon bone. The superior extremities of these bones articulate with
the lower row of carpal bones. The convex extremity of the cannon bone
meets shallow depressions in the superior extremity of the first digital
bone. This is termed the fetlock joint. The anterior and posterior faces of
this region are travelled by the long tendons belonging to the extensor and
flexor muscles of the digit.

THE DIGIT OR TOE is formed by six bones, three of which are termed
accessory or sesamoids. The digital bones may be given numerical names.

THE APPROXIMAL OR THIRD DIGITAL BONE is the shortest long bone in the body.
The two shallow articular cavities belonging to the superior extremity are
completed posteriorly by the two sesamoid bones. The inferior extremity is
smaller than the superior and resembles the inferior extremity of the
cannon bone in shape, excepting that it shows a middle groove. The anterior
and posterior faces are travelled by the tendons of the digital muscles.

THE MIDDLE OR SECOND DIGITAL BONE is quite short. It articulates superiorly
with the first, and inferiorly with the third bone of the digit. The
superior face shows two shallow cavities, and the inferior two convex
surfaces separated by a median groove. The latter face articulates with the
third and navicular bones. The popular name for this articulation is the
coffin joint.

THE THIRD OR DISTAL DIGITAL BONE may be compared to a cone that has been
cut away posteriorly, obliquely downwards and backwards. The superior face
shows two shallow cavities that are completed posteriorly by the superior
face of the coffin or navicular bone. The anterior face is convex and
cribbled by openings, and the inferior face is concave, forming the sole.
Tendons belonging to the digital muscles terminate on the summit and
inferior face of this bone.

THE PELVIS OR HAUNCH is formed by a single bone, the _coxa_ that in the
foetus may be divided into three bones. These are the _ilium, pubis_ and
_ischium_. It belongs to the class of flat bones. Anteriorly it is
flattened from before to behind and directed inward and upward. The
external angle is rugged and is generally termed the angle of the haunch.
The internal face of the opposite angle articulates with the sacrum, to
which it is firmly attached by ligaments. The middle portion is constricted
and forms a neck. The inferior or posterior portion is flattened from above
to below, and directed inward to meet the border of the opposite bone. Just
below the neck and externally, there is a cup-shaped cavity into which the
head of the thigh bone fits. The two coxa, together with the sacral
ligaments (sacrum) and the muscles of the quarter, enclose the pelvic
cavity.

THE REGION OF THE THIGH is formed by the _femur_, the largest long bone in
the body. The superior extremity is formed by a rugged eminence, to which
the heavy muscles of the quarter are attached, and by an articular head.
The inferior extremity is formed by two convex articular surfaces that are
separated by a deep notch, and a third pulley-like articular surface, with
which the patella or knee-cap articulates. The pair of condyles articulates
with the superior extremity of the leg bone. The thigh or femoral region is
heavily muscled.

THE LEG is formed by three bones. The patella, a short bone, has already
been mentioned as articulating with the thigh bone. The tibia and fibula
are the other two bones in the region.

THE TIBIA belongs to the class of long bones and the fibula is quite
rudimentary, being represented by a stylet-shaped bone that lies posterior
to, and along the outer border of the tibia. The superior extremity of the
tibia shows a central spine margined laterally by rather plain articular
faces. It articulates with the thigh bone. The muscles of this region are
divided into two sub-regions, _anterior_ and _posterior_ tibial. The
muscles originate from the lower extremity of the femur and the two bones
in this region, and terminate inferiorly in tendons that are attached to
the bones of the hock, cannon and digit.

THE HOCK OR TARSAL region is formed by six bones. They are described as
forming two rows. In the upper row there are two bones and in the lower
four. They form a series of articulations, the same as the bones of the
knee. Practically all of the movement occurs in the articulation between
one of the large bones in the upper row and the lower extremity of the
tibia. It may be mentioned here that this is the most perfect hinge-joint
in the body. A very large tendon is attached to the summit of the hock.
Other tendons cross and become attached to the hock bones.

The regions of the _hind cannon_ and digit are practically the same as the
corresponding regions of the forefoot.


QUESTIONS

1. Name the different bones of the fore-limb; hind limb.

2. Describe the regions of the shoulder, arm and forearm.

3. Describe the region of the forefoot.

4. Describe the regions of the haunch, thigh and leg.

5. Describe the region of the hindfoot.



CHAPTER XV

UNSOUNDNESSES AND BLEMISHES


GENERAL DISCUSSION.--The value of a horse depends largely on the condition
of the limbs and their ability to do the work for which they are intended.
This fact is frequently overlooked by experienced horsemen, who give
attention to general conformation and action rather than to soundness of
limb.

Diseases affecting the limbs may be classed as _unsoundnesses_ and
_blemishes_. This classification is based on the degree to which the
disease interferes or may interfere with the work that the animal is called
on to perform. Unsoundnesses interfere with the use of the part or the use
of the animal for a certain work; blemishes do not. Such a basis for the
classification of diseases does not enable us to place certain diseased
conditions of the limbs in the unsound, or the blemish class at all times.
A curb may, if it produces lameness, be classed as an unsoundness. If it
does not cause the animal to go lame, and the enlargement on the posterior
border of the hock is small, it is classed as a blemish. A high splint may
place the animal in the unsound class, but usually a low splint is not
considered a serious blemish. This classification is based to a certain
extent on the relative economic importance of the disease, or the influence
that the disease may have on the value of the animal, as well as any
interference with the animal's ability to work.

RECOGNITION OF THE DISEASE.--The seat of the disease may be in a muscle,
tendon, bone or ligament. The general symptom manifested is lameness or
pain. The local symptoms are heat, pain, swelling and bony enlargements.
The degree of lameness and the character of the local lesions vary greatly
in the different cases. When the animal shows a slight lameness and there
is little evidence of any local symptom, it requires the services of a
skilled and experienced person to locate the diseased part. When the part
shows local lesions of disease and the lameness is characteristic,
diagnosis is not difficult.

THE EXAMINATION should be made while the animal is at rest; while standing
in the stall and on level ground; when moved at a walk, or a slow trot on
soft ground, or a hard roadway; and when moved out after resting a few
hours. While examining the animal under the different conditions mentioned,
the examiner must be careful and not pass over any part of a limb without
determining whether it is normal or not. He should note any abnormal
position that the animal may take while standing at rest. Every movement
should be watched closely, as the manner of favoring the part may
characterize the lameness. Negative symptoms of lameness in a part may at
times prove as valuable in forming a diagnosis as positive symptoms.

The resting of either of the front feet, when the horse is standing at
ease, indicates that there is some soreness in the rested limb. _Pointing_
or placing one or both feet well in front of the line of support, when the
animal is standing, usually indicates a diseased condition of the feet. It
is natural for a horse that is standing in a stall to rest the hindfeet
alternately. When the hindfoot is rested because of a soreness in some
portion of the limb, it may be flexed or extended, the weight rested on the
toe, and the foot flexed and bearing practically no weight. In serious
inflammation of the front feet, both feet may be placed well in front of
the normal position, and the hindfeet well under the body.

WHEN EXAMINING A HORSE, the blanket or harness should be removed. The horse
should have on an open bridle or halter, and the attendant should give it
as much freedom of the head as possible. The examiner should examine each
limb carefully and note any symptom of disease that may be present. The
attendant should walk the animal straight away from the person making the
examination, toward, and past him, so that the animal's movements can be
observed from both sides, from behind and in front. This examination should
be repeated with the horse at a slow trot.

The character of the lameness may enable us to locate the seat of the
disease. We must first determine in which limb the animal is lame. This
part of the diagnosis is not difficult. The pain suffered every time weight
is thrown on the diseased limb causes the horse to step quickly and shift
as much of the body weight as possible on the well foot. The foot of the
lame limb is jerked up rather quickly after weight is thrown on it. This
favoring of the part varies in the different diseases. When the foot of the
sound limb comes to the ground, more weight than common is placed on it. If
the seat of the lameness is in a front limb, there is a decided nodding or
movement of the head downward when the weight is placed on the well foot.
If both forefeet are diseased, the animal steps shorter and more quickly
than common. Lameness in a hind limb is characterized by more or less
dropping of the quarter of the well limb when weight is thrown on it, and
sometimes by a "hitch" or elevation of the quarter of the diseased limb
when it is carried forward.

Unless there are _local symptoms of disease_ present, it may be quite
difficult to locate the seat of lameness. Sometimes local symptoms are
misleading. After the lameness has been located in a certain limb, its
movement must be carefully noted in order to detect the part favored. If
the lameness is not characteristic enough to enable the examiner to locate
the seat of it, it is then necessary to put the animal through some
movement that may emphasize the soreness in the part. The animal may show a
certain reluctance to throw weight on the limb when turned to the right or
left. Moving the horse in a small circle with the lame limb on the outside
may cause the animal to use the muscles of the shoulder more freely, and
emphasize any soreness that may be present. If the lame limb is on the
inside, soreness anywhere in the foot may be increased, because of the
extra weight thrown on this portion of the limb. Moving the animal over a
hard driveway may increase the pain resulting from an inflammation of the
feet. Causing the animal to trot on soft ground, step over high objects,
flexing, extending, abducting and adducting the part may enable the
examiner to locate the exact group of shoulder or arm muscles involved by
the disease.

IN EXAMINING THE FEET it may be necessary to remove the shoes and practise
percussion and pressure over the region of the sole. In some forms of
lameness it may be necessary to destroy the sensation in the foot by
injecting cocaine along the course of the nerves that supply the foot
before arriving at a definite diagnosis.


QUESTIONS

1. Define the term unsoundness and give an example.

2. Define the term blemish and give an example.

3. Give the general method of examining a horse for soundness.



CHAPTER XVI

DISEASES OF THE FORE-LIMB


SPRAINS AND INJURIES IN THE REGION OF THE SHOULDER.--Sprains and injuries
of the structures in the shoulder region are more common in horses that are
called on to do heavy work than among driving horses.

The following _causes_ may be mentioned: Ill-fitting collars, pulling heavy
loads over uneven streets or soft ground, where the footing is not secure,
and slipping are common causes. Young horses that do not know how to pull,
or horses that are tired out by hard work, are predisposed to muscular
strain, and are apt to suffer injury if forced to do heavy work. Sore
shoulders, or an ignorant driver, may cause the animal to pull awkwardly
and throw more strain on certain groups of muscles than they can stand.
Rheumatism frequently causes shoulder lameness. The muscle usually affected
by rheumatism is the large muscle extending from the region of the point of
the shoulder to the summit of the head.

[Illustration: FIG. 31.--Shoulder lameness.]

_The symptoms_ of shoulder lameness vary in the different cases. The horse
may walk without going lame, but when made to trot lameness is quite
noticeable. The animal may point with the foot of the diseased limb,
holding it forward, but squarely on the floor. In severe strain, little
weight is thrown on the limb and the lameness is marked (Fig. 31). In
"shoulder slip" the head of the arm bone pushes outward every time the
animal throws weight on the limb. This luxation can be noticed best when
standing in front of the animal. Marked atrophy of the external shoulder
muscles may occur. Such atrophy may appear and disappear quickly, and may
result from an injury to the nerve supply of the muscle as well as from
favoring the part. Atrophy of the shoulder may occur if the animal is lame
in other regions of the limb, especially the feet. The outcome of shoulder
lameness is favorable if the disease causing it is given prompt treatment.

_Rest_ is a very important part of the _treatment_. It may be advisable to
restrict the horse's movements by placing it in a single stall, and tying
the animal so that it can not lie down. This should be continued for at
least one week. If the horse is restless, it should be given a box-stall or
turned out in a small lot alone. It should be watered and fed in the
quarters where confined. The _local treatment_ consists in applying mild
liniments or blisters to the shoulder. It is not advisable, however, to
apply a blister if the muscles feel hot and tender.

CAPPED ELBOW, "SHOE-BOIL."--Capped elbow is an inflammation of the bursa at
the posterior surface of the elbow (Fig. 32). The swelling that results is
usually sharply defined. It may feel abnormally warm and doughy, and it may
be painful. Later, the enlargement may be well defined and hard. Sometimes
the skin is indurated and lies in folds, or the shoe-boil shows abrasions
on its surface and fistulous openings leading from abscess centres. The
cystic or soft tumor is a common form. Such an enlargement fluctuates on
pressure, and when opened, a blood-stained fluid escapes. All forms of
capped elbow tend to become chronic.

_The treatment_ is both preventive and local. As capped elbow is caused by
bruising the part with the hoof or heel of the shoe, the preventive
treatment consists in hindering the animal from taking a position that may
favor injury to the part. Confining the animal in a small stall and tying
it with too short a halter strap favors a sternal position when lying down.
A roomy stall that permits the animal to stretch or change position is an
important preventive measure. Shoes that project beyond the quarters should
be avoided. The elbow may be protected by placing a thick pad over the
heels when the animal is in the stable.

[Illustration: FIG. 32.--Shoe-boil.]

_Local treatment_ varies according to the character of the enlargement.
Soft, doughy swellings may be treated by application of cold, iodine and
blisters. The cystic form of tumor must be opened, the fluid removed and
the lining membrane destroyed by the injection of tincture of iodine. Hard,
indurated shoe-boils may be treated by completely removing the diseased
tissue. The surgical treatment of capped elbow requires the service of an
experienced veterinarian. His efforts may prove a complete failure, unless
the irritation to the part by the shoe or hoof is prevented.

INJURIES TO THE KNEE (BROKEN KNEE).--Horses frequently fall and bruise or
lacerate the knee when moving at trot or canter. The injury varies
according to the force of the fall, and the character of the road that the
animal is travelling over. Some individuals are more liable to suffer from
this class of injuries than others. Horses that are weak-kneed because of
poor conformation, or knee-sprung, are inclined to stumble. Careless
driving, especially if the animal is tired, predisposes it to this class of
injury. Because of the predisposition toward stumbling on the part of some
horses, scars on the front of the knee are termed broken knee, and the
animal is considered unsound.

_The symptoms_ vary with the extent of the injury. Slight bruises or
abrasions result in local swelling and soreness that disappear within a few
days. Laceration of skin interferes with the movement of the knee and the
animal may be quite lame. The part becomes swollen and painful. In injuries
involving the sheaths of the tendons and the synovial membrane, the pain is
severe and the accompanying inflammation may take on a serious form.

_The preventive treatment_ should not be overlooked. Horses should be
trained to carry the head at a proper height when moving. The driver should
handle the reins properly and keep his attention on the horse or horses
that he is driving. Superficial bruises require no special treatment other
than rest. Laceration of the skin and underlying tissue requires complete
rest and careful removal of any particles, of dirt and gravel that may be
present in the wound. Shreds of tissue that may take no part in the healing
should be cut away. The hair in the region of the wound should be trimmed
short. Careful and repeated dressings with antiseptics are necessary until
the inflammation has largely disappeared and healing is rapidly taking
place. It may be advisable to tie the horse in the stall so that it can not
lie down.

DISTENDED SYNOVIAL SACS, JOINT SHEATHS AND BURSAE, "GALLS."--Soft
enlargements may occur in the region of the knee and fetlock. They are
commonly termed "galls," "wind-galls," or "road-puffs." They are usually
due to the sheaths surrounding the tendons becoming distended with synovia.
"Galls" are caused by strains, direct injury to the part and severe,
continuous work. Certain individuals may develop this class of blemishes
without being subject to any unusual conditions. This condition is seldom
accompanied by lameness.

_The treatment_ may vary in the different cases. If the distended sheath,
or bursal enlargement, is caused by a direct injury or strain, cold
bandages should be applied and the part given as complete rest as possible.
"Wind-galls" may be removed by a surgical operation. It is not advisable to
attempt the removal of "road-puffs." Rest, stimulating leg washes and
bandages may temporarily remove the latter.

SPRUNG KNEES (BUCK KNEES).--This condition of the knee is characterized by
the partly flexed condition of the region. It is best observed by standing
to one side of the horse (Fig. 33). Instead of the forearm and cannon
regions appearing perpendicular or in line, they are directed forward. This
condition may exist in varying degrees. Some individuals show it to a
slight degree, the condition being accompanied by a weakness or shakiness
of the knee when standing at rest. Sometimes, but one knee is involved.

_The causes_ of this unsoundness are hereditary and accidental. Weak knees
due to faulty conformation seldom escape becoming sprung in animals that
are given hard work. Severe and continuous driving is a common factor in
the production of this condition. Strains of the flexor muscles of the
region may cause it. The retraction of the flexor muscles and their tendons
and the aponeurosis of the antibrachial region occurs in this disorder and
prevents the animal from extending the knee.

The region is greatly weakened by this condition and the animal may be
unfitted for active work. For this reason the value of the animal is
greatly diminished.

_Treatment_ is unsatisfactory. The preventive treatment consists in not
breeding animals that have poorly conformed knees and using the proper
judgment in working young horses and when driving or riding horses. Certain
cases may be greatly benefited by sectioning the tendons of the external
and middle flexors of the metacarpi. To insure a successful outcome in any
case that is operated on, a long period of rest is required.

[Illustration: FIG. 33.--Sprung knees.]

[Illustration: FIG. 34.--Splints.]

SPLINTS.--A splint is a bony enlargement situated along the line of
articulation between the splint and cannon bones (Fig. 34). This blemish is
due to an inflammation of the periosteum. It is a very common blemish and
is generally located along the splint bones of the forefeet, especially the
internal ones.

_Splints are caused_ by strains and rupture of the ligament that binds the
splint bone to the cannon bone. The result is an inflammation of the
periosteum. Slipping, or an unbalanced condition of the foot, may cause
this injury by distributing the weight unequally on the splint bones.
Faulty action and bad shoeing may cause the horse to strike and bruise the
region.

_Symptoms of lameness_ are not always present. A high splint involving the
articulation between the lower row of carpal, splint and cannon bones may
be considered an unsoundness, because of the persistent character of the
lameness. The animal may show little or no lameness when walked, but if
moved at a trot, especially over a hard roadway, it may show marked
lameness. The local inflammation is characterized by a small swelling lying
along the splint bone, that feels hot and may pit on pressure. After a time
the inflammation disappears and is replaced by a hard, bony enlargement.
When this occurs the lameness disappears.

_The preventive treatment_ consists in keeping the feet of young horses in
proper balance by frequent trimming and proper shoeing. This attention is
very necessary in young colts that are running in pasture. It is very
advisable to rest the animal during the period of inflammation. Cold
bandages should be applied. As soon as the inflammation has subsided mild
counterirritants and absorbents may be used. In. case the lameness
persists, more severe counterirritation is indicated.

INFLAMMATION OF THE FLEXOR TENDONS OF THE DIGIT.--The large tendons
posterior to the foot and the suspensory ligament that separates them from
the cannon bone frequently become inflamed. Sometimes complete rupture of
one or more of these structures occurs. The lighter breeds of horses are
the most frequent sufferers. Because of the greater strain thrown on the
tendons of the forefeet, inflammation of these tendons is far more common
than it is in the hindfoot. Diseased conditions of the hind tendons are
usually due to other causes than strain.

The following _predisposing_ and _accidental causes_ should be considered:
Weak flexor tendons and heavy bodies predispose animals to inflammation of
the tendons and suspensory ligament; quality, not size, is the factor to
consider when judging the strength of a tendon; long, slender pasterns
increase the strain on these structures, and this mechanical strain is
further increased by low heels and long toes; the character of the work and
the condition of the road that the animal travels over are important
factors to consider; trotting and running horses more often suffer from
injuries to tendons and ligaments than draft horses; travelling at a high
rate of speed over an uneven road, slipping and catching the foot in a rut
or car track, are common causes; bruises and wounds may result in the
tendons becoming inflamed; inflammation of the tendinous sheaths and the
tendons as well sometimes occurs in influenza.

_Lameness_ is a prominent _symptom._ The pastern is held in a more upright
position than normal. When the animal is standing, the foot is rested on
the toe, and it may take advantage of any uneven place on which to rest the
heel. In severe strains the local symptoms are quite prominent. The tendons
may be hot and swollen. Pressure may cause the animal pain. In chronic
tendinitis the tendon may be thickened and rough or knotty. Pain is not a
prominent symptom in this class of cases. Shortening of the inflamed tendon
may occur, causing the animal to knuckle over. Rupture of one or more of
the tendons and the suspensory ligament can be recognized by the abnormal
extension of the pastern. If the ruptured tendon heals, it always results
in a thickening at the point of the rupture that gives the tendons a bowed
appearance. This is termed bowed-tendon.

The lameness resulting from an inflammation of tendons resembles that
resulting from strains and injuries to the fetlock joint, especially in the
region of the sesamoid bones.

INFLAMMATION OF THE SESAMOID BONES differs slightly from the former.
Pressure over the posterior region of the fetlock may cause the animal
pain. The lameness shows a tendency to disappear with rest and reappear
when the animal is again worked. Lameness is most prominent in some cases
when the animal is first moved out. There may be a lack of local symptoms,
such as heat and swelling. It is not uncommon for a bony enlargement to
form on the sesamoid bone after a few months or a year.

The following _treatment_ is recommended. Horses that have a poor quality
of tendon and weak fetlocks and pasterns should not be used for breeding
purposes. Careful driving would prevent a large percentage of injuries to
tendons. The most important treatment for all injuries due to strains is
rest. In all cases of severe strain to the structures in this region, it is
very advisable to apply a plaster bandage. This should be left on for at
least two weeks. When the acute inflammation has subsided, counterirritants
may be applied. Either cold or hot applications are recommended. Cold
applications are to be preferred at the beginning of the inflammation.
Covering the tendons with a cold bandage, or with a heavy layer of
antiphlogistin, is recommended. The horse should not be worked until after
the tendons have had an opportunity to completely recover from the
inflammation.

CONTRACTED TENDONS, KNUCKLING-OVER.--New-born foals are sometimes unable to
stand on their front feet because of the excessive knuckling-over. The colt
may walk on the front of the pastern and fetlock. This sometimes results in
severe injury to the skin and the underlying tissues.

Knuckling-over in the mature horse is not always due to contracted tendons.
It may occur as a symptom of inflammation of the flexor tendons, ligaments
of the fetlock joint and the articulation as well. It may be noticed in
animals that have ring-bone, or coffin-joint lameness.

The most _common cause_ for this unsoundness is inflammation of the muscles
and tendons of the flexors of the digit. As a result of long standing or
severe inflammation, shortening of these structures occurs in consequence
of the contraction of the inflammatory or cicatricial tissue.
Knuckling-over in the newborn colt is commonly caused by a weakness or lack
of innervation of the extensor muscle of the digit. Judging from the quick
recovery that usually occurs, other causes for this condition are seldom
present.

_The treatment_ recommended for the new-born colt is supporting the fetlock
with a light plaster bandage. This should be applied very soon after birth
in order to prevent bruising of the fetlock. A light cheese-cloth bandage
should be applied to the limb from the hoof to the knee. The colt is laid
on its side, the toe extended as much as possible, and the plaster bandage
applied. This should be removed in about one week and fresh bandages
applied. In about two weeks the young animal is usually able to walk on the
toe. As soon as it is able to do this a bandage is unnecessary. It is not
advisable to turn the colt outside if there is any chance for the bandages
to become wet.

Knuckling-over due to faulty conformation is difficult to correct. Light
work and careful shoeing are the most valuable preventive measures in young
horses. Sprains and injuries to the region of the fetlock should receive
the necessary treatment. The treatment for contracted tendon is largely
surgical and consists in sectioning it.

INJURIES CAUSED BY INTERFERING.--Horses that have faulty action may strike
the opposite fetlock with the moving foot, the inside of the opposite limb
in the region of the knee, and the quarters of the front foot with the shoe
of the hindfoot. It is very common for horses to "brush" the inside of the
hind fetlock with the opposite foot when trotting, especially if tired.
Interfering in the front feet is less common. Striking the inside of the
region of the knee with the opposite foot or "_speedy cutting_" occurs in
driving and speed horses. Both of the latter forms of interfering may be
considered unsoundnesses.

The most _common cause_ of interfering is faulty conformation, such as
narrowness of the chest or pelvis, faulty conformation of the limbs and
irregularity in the action of the joints. Shoeing and the condition of the
feet are also important factors. Animals that have a narrow chest or pelvis
interfere because the legs are placed too closely together. Turning in of
the knees or "knock-kneed," winging in or out of the feet, or any other
defective conformation of the limbs that tends to prevent the animal from
moving the feet in line, lead to serious interfering. A wide-spreading
hoof, an unbalanced condition of the foot and improper fitting of the shoes
are common causes for interfering in horses that would otherwise move the
feet in line. Debility from disease and overwork may cause the animal to
interfere temporarily. An unbalanced gait and shortness of the body are the
common causes for injuries to the quarters.

All degrees of injury to the part struck by the shoe or wall of the foot
may be noted. Horses that interfere lightly, wear the hair off and produce
slight abrasions of the skin on the inside of the fetlock. Sometimes the
skin is bruised, inflamed or scarred. Injuries to the inside of the knee
and quarter are the most serious. Lameness, inflammation of the periosteum
and bony enlargement may result from "speedy cutting." Deep wounds in the
region of the heel or quarter may occur when a horse strikes this part with
the shoe of the hindfoot in moving at a high rate of speed.

_The treatment_ is largely preventive. No doubt many cases of interfering
could be prevented by careful training and balancing of the foot when the
animal is growing and developing. The feet of colts should be trimmed every
three or four weeks. Interfering in the hindfeet may be stopped by noting
the character of the animal's gait and the portion of the wall that strikes
the part, and by practising intelligent methods of shoeing. Slight injuries
should be treated by the application of antiseptic powders. The treatment
for injuries to the periosteum is the same as that recommended for splints.
As a last resort boots and button rings may be used for the purpose of
preventing serious injury to that part which is struck by the foot.

RING-BONE.--Chronic inflammation of the articulation between the first and
second bones of the digit is termed ring-bone (Fig. 35). Not all ring-bones
involve the articular surfaces. The periarticular, or false ring-bone, is a
chronic inflammation of the bone near the articular surface. The bony
enlargement varies in size. It may form a ring encircling the part, or it
may be limited to the lateral surface of the joint. The bony enlargement
may be so small as to be detected only by a careful examination. Ring-bone
may occur on any of the feet, but it is said to be more common in the front
feet.

[Illustration: FIG. 35.--Bones of digit, showing side bones and ring-bones,
and normal bones of digit.]

_The predisposing cause_ of ring-bone is faulty conformation. Long, weak
pasterns that are predisposed to strains, upright pasterns, especially if
small, and exposed to concussion and jarring, and crooked feet that
distribute the weight on the part irregularly are important factors in the
production of ring-bones. The _external causes_ are sprains or any injury
to the region. _Lameness_ is nearly always present. The degree of lameness
varies, and does not depend altogether on the size of the bony enlargement.
Large ring-bones interfere with the movement of the tendon. Lameness is
most pronounced when weight is thrown on one foot, the later phase of the
step being shortened and the pastern more upright. Some cases improve with
rest, but the lameness returns when the animal is given hard work.

_The preventive treatment_ consists in giving the necessary attention to
the feet of young animals, by trimming the wall frequently and keeping the
feet in balance and the careful selection of breeding stock. Resting the
animal, keeping the foot that has the ring-bone on it in proper balance and
counterirritation by means of blisters and cautery (searing) are important
lines of treatment. Shortening the toe and raising the heel, if necessary,
greatly relieves the lameness in some cases. Sectioning the sensory nerves
that go to the part should not be practised, unless in exceptional cases.


QUESTIONS

 1. Give the causes of shoulder lameness; give the treatment.

 2. Describe capped elbow; give the treatment.

 3. What is "broken knee"?

 4. What are "wind-galls" and "road-puffs"?

 5. Give the cause and treatment of sprung-knee.

 6. Give the cause and treatment of splints.

 7. What class of horses most commonly have strained tendons? Give the
    causes and treatment of this form of lameness.

 8. Give the treatment of contracted tendons in the new-born colt.

 9. Give the causes for interfering.

10. What are the different forms of ring-bone? Give the causes and
    treatment of ring-bone.



CHAPTER XVII

DISEASES OF THE FOOT


GENERAL DISCUSSION.--The foot of the horse as generally spoken of, includes
the hoof and the structures that are enclosed by it (Fig. 36). It may be
divided into three parts, the insensitive and sensitive structures and the
bony core. The _insensitive foot_ or _hoof_ is divided into wall, sole,
frog and bars. The _sensitive foot_ is divided into vascular tissue and
elastic apparatus. The vascular tissue is in turn divided into coronary
cushion, laminae and velvety tissue. The elastic apparatus is divided into
plantar cushion and fibro-cartilages. The _bony core_ is formed by the
navicular and third digital bones. The hoof and vascular tissue in turn
enclose the elastic apparatus and bony core.

[Illustration: FIG. 36.--Photograph of a model of the foot: wall; sensitive
tissue; plantar cushion, inferior dark portion, sole and frog; lateral
cartilage; and pedal bone.]

THE WALL forms that portion of the hoof seen when the foot rests on the
ground (Fig. 37). It is covered by a thin layer of horny tissue, the
_peripole,_ that coats over the wall and assists in preventing its drying
out. On lifting the foot and examining its inferior surface, it is noticed
that the wall at the heels is inflected under the foot and in a forward
direction. This portion of the wall is termed the _bars._ Within the
bearing margin of the wall and in front of the bars is a thick, concave,
horny plate that forms the _sole._ At the heels and between the bars is a
wedge-shaped mass of rather soft horny tissue that projects forward into
the sole. This is the _foot pad_ or _horny frog._ It is divided into two
lateral portions by a medium cleft.

THE CORONARY CUSHION projects into the upper border of the wall. It is
covered with vascular papillae which secrete the horny fibres that form the
wall. The _vascular laminae_ are leaf-like projections, the sides of which
are covered by secondary leaves. _Horny laminae_, arranged the same as
vascular laminae, line the wall. These two structures are so firmly united
that it is impossible to tear them apart without destroying the tissue. The
_velvety tissue_ covers all of the inferior surface of the foot, with the
exception of the bars. As the name indicates, its surface is covered by
vascular papillae that resemble the ply on velvet. It is firmly united to
the horny sole which it secretes.

[Illustration: FIG. 37.--Foot showing neglect in trimming wall.]

The lateral cartilages are attached to the posterior angles of the pedal
bone. They are flattened from side to side, and the portion that projects
above the coronary cushion may be felt by pressing on the skin that covers
it. The _plantar cushion_ is a wedge-shaped piece of tissue formed by
interlacing connective-tissue fibres and fat. It is limited on each side by
the lateral cartilages. Its inferior face is moulded to the frog.

THE BONY CORE formed by the last bone of the digit and the coffin bone was
described briefly with the other foot bones. A very important bursa,
because it is so frequently inflamed in coffin-joint lameness, facilitates
the gliding of the flexor tendon over the navicular bone before it becomes
attached to the inferior face of the pedal or digital bone.

SIDE-BONES.--This is a chronic inflammation of the lateral cartilages of
the foot that results in their ossification (Fig. 38). This unsoundness is
common in heavy horses, especially if worked on city streets. The
inflammation affects the cartilages of the front feet, rarely those of the
hindfeet.

_The hereditary tendency_ toward the development of side-bones is an
important predisposing factor. It is not uncommon to meet with this
unsoundness in young horses that have never been worked. Low, weak heels,
flat, spreading feet, or any other faulty conformation of the foot are
predisposing factors.

[Illustration: FIG. 38.--A very large side bone.]

The character of the work is an important _exciting cause._ Continuous work
over paved streets, especially if the horse is shod with high-heeled shoes,
increases the shock received by the elastic apparatus of the foot. This
produces more or less irritation to the lateral cartilages, which may
result in their complete ossification. Punctured wounds in the regions of
the cartilage may cause it to become inflamed and changed to bone.

The following _symptoms_ may be noted. Farm horses that have side-bones
seldom show lameness. This is because they are worked on soft ground and
not on a hard street or road. Driving and dray horses may step short with
the front feet, or show a stilty action. This may disappear with exercise.
The lameness is sometimes marked. The local diseased changes are the
greatest help in the recognition of side-bones. Horses should not be passed
as sound without making a careful examination of the lateral cartilages.
This examination is made by pressure over the region of the cartilage with
the thumb or fingers. This is for the purpose of testing its elasticity. If
it feels rigid and rough, the cartilaginous tissue has been replaced by
bony tissue, and the animal should be classed as unsound.

_The treatment_ is largely preventive. Horses with side-bones should not be
bred. It is not advisable to use horses with side-bones on the road or city
streets. Shoeing with rubber pads may help in overcoming the concussion and
relieve the lameness. Sectioning the sensory nerves going to this portion
of the foot is advisable in driving horses. Rest and counterirritation
relieve the lameness for a short time.

NAVICULAR DISEASE.--In navicular disease the bursa, flexor tendon, and
navicular bone may become chronically inflamed. Because of the seat of the
lameness, it is commonly known as "coffin-joint" lameness. This disease
affects standard and thoroughbred horses more often than it does the
coarser breeds. One or both front feet may be affected (Fig. 39).

_Hereditary causes_ are largely responsible for navicular disease. The
tendency toward this disease probably depends on such peculiarities of
conformation as narrow, weak, high heels, long pasterns and too long a toe.
The character of the work is an important factor. Hurried, rapid movements
throw considerable strain on the navicular region, increasing the danger
from injury. This is, no doubt, one reason for "coffin-joint" lameness
being more common in driving and speed horses than in slow-going work
animals. Rheumatic inflammation, bad shoeing and punctured wounds in the
region of the bursa many cause it.

[Illustration: FIG. 39.--A case of navicular disease involving one front
foot. The diseased foot is the smaller.]

The _first symptom_ usually noted is a tendency to stumble. When standing
in the stable, the animal "points" or rests the diseased foot. Sometimes it
rests the heel of the lame foot on the wall of the opposite foot. If both
feet are affected, the animal may rest them alternately, or take a position
with both feet well in front of the normal position. The inflamed
structures are so covered by other tissues that it is difficult to detect
the local inflammation, or cause the animal to flinch by applying pressure
over the region. As the disease becomes more advanced, the lameness becomes
permanent. The limb is carried forward stiffly and rapidly and the animal
stumbles when travelling over rough ground. In time, because of the little
weight thrown on the posterior portion of the foot, the quarters may become
higher, contracted and more upright and the frog smaller. If one foot is
diseased, it becomes smaller than the opposite foot.

The following _preventive measures_ may be recommended. We should not use
animals having faulty conformation of the feet for breeding, because the
offspring of such individuals have an inherent tendency toward navicular
and other foot diseases. Animals that have "coffin-joint" lameness should
be allowed to run in pasture as much as possible, because natural
conditions help to keep down the inflammation and soreness and promote a
more healthy condition of the foot. In shoeing the horse it is best to
shorten the toe and raise the heel. It is advisable in the more favorable
cases to cut the sensory nerves of the foot. This operation destroys the
sensation in the foot, and should not be performed on feet with weak heels,
or that are wide or spreading.

[Illustration: FIG. 40.--An improperly shod foot; note the manner in which
the wall is cut away at the toe.]

CONTRACTED QUARTERS.--This condition of the feet is characterized by the
foot becoming narrow in its posterior portion. One or both of the quarters
may be affected. It is principally observed in the forefeet.

The _causes_ of contraction of the foot may be classed as _predisposing_,
_secondary_ and _exciting_. It may accompany chronic diseases of the foot,
such as navicular disease and side-bones. Weak heels is the principal
predisposing factor. Any condition that tends to prevent the hoof from
taking up moisture, or causes it to lose moisture, may cause the horn to
lose flexibility and contract. This is one of the reasons why horses that
are worked continuously in cities, or used for driving, frequently develop
contracted feet. Ill-fitting shoes, excessive rasping of the wall and bars,
and allowing the shoes to stay on the foot for too long a time are
responsible to a very large degree for this disorder of the foot (Fig. 40).

The following _local symptoms_ may occur: The wall of the foot at the
quarters may appear drawn in at its superior or inferior portion. Sometimes
one or both quarters are perpendicular, or nearly so. The foot then appears
too narrow at the heel, too elongated and less rounded than normal. The
changes in the appearance of the inferior surface of the hoof vary. The
changes here may be so slight that they are not noticed. In well advanced
and neglected cases the arch of the sole is increased, the frog is narrow
and atrophied and the bars high and perpendicular. Corns may accompany the
contraction. The foot may feel feverish. The animal may manifest the pain
in the feet when standing at rest by pointing and changing their position.
When lameness is present, it may resemble that occurring in inflammation of
lateral cartilages and navicular disease.

_Preventive treatment_ is of the greatest importance. This consists in
giving the feet an opportunity to take up moisture when they are exposed to
abnormal conditions and become feverish. Under such conditions, it is
advisable to occasionally remove the shoes and turn the animal into a
pasture or lot. It is best to do this in the fall or winter when the ground
is wet. If this can not be practised, the shoes should be removed and a
poultice of ground flaxseed and bran, equal parts, applied to the feet for
a period of eight or ten hours, daily for a week or two. A plank trough six
inches deep, two feet wide and as long as the stall is wide may be filled
with a stiff clay, and the horse made to stand with its front feet in the
clay bath for ten or twelve hours daily. When grooming the horse, the foot
should be cleaned with a foot-hook and washed with clean water. Hoof
ointments should be avoided so far as possible. The importance of fitting
the shoe to the foot, avoiding the too free use of the rasp and hoof knife
and resetting or changing the shoe when necessary can not be overestimated.
Shoeing the animal with a special shoe is sometimes necessary. It is not
advisable to attempt the forcible expansion of the quarters. Lowering the
heels by careful trimming of the wall and sole and permitting frog pressure
may be all the special attention required.

SAND-CRACK.--A fissure in the wall of the foot running in the same
direction as the horny fibres, or a seam in the wall resulting from the
healing of the fissure is termed sand-crack. The position and extent of the
fissure or seam vary. It may involve the wall of the _toe_ (toe-crack)
(Fig. 41) or _quarter_ (quarter-crack) (Fig. 42). It is _superficial_ or
_deep_, according to the thickness of the wall involved; _complete_ or
_incomplete_, depending on whether it extends from the bearing margin of
the wall to the coronary band or only a portion of the distance; _simple_,
when the horny tissue only is involved; and _complicated_, when the
sensitive tissue beneath becomes injured and inflamed. Cracks of long
standing usually have thick, rough margins.

_The causes_ of this unsoundness are poor quality of horn, improper care
and injuries. Sand-cracks commonly occur in hoofs that are dry and brittle
and have thin walls. In young horses incomplete cracks due to the wall
becoming long and breaking off in large pieces are common. Unequal
distribution of weight, the result of unskilled shoeing, or any other
condition that may cause the foot to become unbalanced, using the foot rasp
too freely, and such diseases as quittor, corns and contracted quarters
subject the animal to this form of unsoundness. Any injury to the coronary
cushion that secretes the fibres of the horny wall may result in either
toe- or quarter-crack. Treads and barb-wire cuts are common injuries to the
region of the coronet.

_The preventive treatment_ consists in preserving a healthy condition of
the horn by giving the foot the necessary care and attention in the way of
proper trimming and shoeing, and providing it with the necessary moisture
by means of foot-baths, wet clay and poultices. Quarter-cracks respond to
treatment more quickly than toe-cracks. The treatment is practically the
same for both. This consists in preventing motion in the margins of the
fissure so far as possible.

[Illustration: FIG. 41.--Toe-cracks.]

[Illustration: FIG. 42.--Quarter-crack caused by barb-wire cut.]

_The treatment for fissures_ in the region of the toe and quarter is as
follows: The wall should be cut away along the margins of the crack until
it is quite thin; and extra nail holes should be made in the shoe, and a
nail driven into the bearing margin of the wall a little to each side of
the fissure. The wall at the toe should be shortened and the toe of the
shoe rolled if the animal's work permits the use of this kind of a shoe.

The margins of a quarter-crack and the wall just posterior and below it
should be cut away until quite thin. The bearing margin should then be
trimmed so that it does not rest on the shoe. A bar shoe that does not
press on the frog may be used. Light blisters to the region of the coronet
help in stimulating the growth of the horn. Rest is advisable.

CORNS.--This term is applied to injuries to the foot caused by bruises or
continuous pressure to the posterior portion of the sole. This condition is
common in the forefeet.

_The predisposing causes_ are faulty conformation that favors pressure from
the shoe on the sole between the bars and wall and weak heels. Corns are
commonly met with in feet having contracted quarters. The principal
_external causes_ are wrong methods of shoeing and allowing the shoes to
remain on the feet for too long a period.

_A common symptom_ of corns is lameness. In order to relieve the pressure
over the inflamed part, the animal stands with the foot slightly flexed at
the fetlock. The lameness is not characteristic. It is only by a local
examination of the foot, made by pressing on the sole or cutting away the
horn, that we are able to form a positive diagnosis.

We describe the _diseased changes_ by using the terms _dry_, _moist_ and
_suppurative corns_. In the _dry corn_ we find the horn stained and
infiltrated with blood. In the _moist corn_ the hoof may be colored the
same as in the former, but in addition there is a space between the
vascular and horny tissue that is filled with a serous-like fluid. If this
collection of fluid becomes infected with pus organisms and is changed to
pus, it is then termed a _suppurative corn_. Sometimes the pus pushes its
way upward and backward between the sensitive laminae and the wall, and
makes its appearance at the margin of the coronary band in the region of
the quarters or heels. This usually occurs when the tissues beneath the
horny frog become bruised or the sensitive tissue pricked by a nail. It is
commonly termed "gravelled." Pus rarely breaks through the thick horny
tissue, but follows the wall and breaks through the skin where it meets
with the least resistance. Corns may be considered a serious unsoundness in
driving horses.

_The treatment_ is largely preventive. Trimming the foot and fitting the
shoe properly are important preventive measures. The practice of cutting
away the bars and sole or "opening up the heels," as it is commonly termed,
should be condemned. This method of trimming the foot instead of preventing
corns is a very common factor in producing them. The shoe should not be too
short or too narrow. It should follow the outline of the wall and rest
evenly on its bearing margin. If this is practised, weakening the wall by
cutting off that portion allowed to project beyond the shoe is unnecessary.
Feet that have low heels and large, prominent frogs should be shod with
shoes thick at the heels. The best line of treatment for a horse that is
subject to corns is to remove the shoes and allow the animal to run in a
pasture. If this is impossible, poulticing the feet or standing the animal
in moist clay will help in relieving the soreness. Excessive cutting away
of the horny sole is contra-indicated. Suppurative corns should be given
proper drainage and treatment.

LAMINITIS, "FOUNDER."--This is an inflammation of the sensitive or vascular
stricture of the foot. The inflammation may be acute, subacute or chronic.
Stockmen frequently use a classification for laminitis based on the causes.
Feed, road and water founder are common terms used in speaking of this
disease. The inflammation is usually limited to the front feet.

_The causes_ of laminitis are overfeeding, sudden changes in the feed,
drinking a large quantity of water when the animal is overheated,
overexertion, exhaustion and chilling of the body by standing the animal in
a cold draft. It may be associated with such diseases as rheumatism,
influenza and colic.

_The symptoms_ vary in the different forms of the disease. Pain is the most
characteristic symptom. The sensitive or vascular structure of the foot has
an abundant supply of sensory nerves, and, as it is situated between the
hoof and the bony core, the pressure and pain resulting from the
inflammation are severe.

In the _acute form_ general symptoms are manifested. The appetite is
impaired, the body temperature elevated and the pulse beats and
respirations quickened. If the inflammation is severe, the animal prefers
to lie down. This is especially true if all four feet are inflamed. In most
cases the horse stands with the forefeet well forward and the hind feet in
front of their normal position and under the body. The affected feet are
feverish and very sensitive to jarring or pressure. Moving about increases
the pain in the feet, and it may be very difficult to make the animal step
about the stall.

In the _subacute form_ the symptoms are less severe. The irregularity in
the gait is especially noticeable when the animal is turned quickly. The
local symptoms are less marked than in the acute form and the general
symptoms may be absent.

_The chronic form_ is characterized by changes in the shape and appearance
of the hoofs (Fig. 43). The wall shows prominent ridges or rings, the toe
may be concave, thick and long and the sole less arched than usual, or
convex. The degree of lameness varies. It is more noticeable when the horse
is moved over a hard roadway than if moved over soft ground. One attack of
laminitis may predispose the animal to a second attack.

_The prognosis_ depends on the character of the inflammation and the
promptness and thoroughness of the treatment. Acute laminitis may respond
to prompt, careful treatment in from ten to fourteen days. Subacute
laminitis responds readily to treatment. The prognosis is least favorable
in the chronic form.

_The preventive treatment_ is very important. Dietetic causes are
responsible for a large percentage of the cases of this disease. Horses
that are accustomed to being fed and watered at irregular periods and after
severe or unusual exercise seem to be able to stand this treatment better
than animals that are more carefully cared for, but even this class of
animals do not always escape injury. Stockmen should realize the danger of
producing an inflammation of the feet by feeding grain and giving cold
water to horses immediately after severe exercise. Overfeeding should also
be avoided. Careful nursing may prevent the occurrence of laminitis as a
complication of other diseases.

[Illustration: FIG. 43.--This foot shows the changes in shape and
appearance of wall and sole occurring in chronic laminitis.]

_The treatment_ of the inflammation is as follows: The removal of the shoes
and the necessary trimming of the foot should be practised early in the
inflammation; the horse should be placed in a roomy box-stall that is well
bedded with cut straw; during the cool weather it may be necessary to
blanket the animal; if the weather is hot and the flies annoy the patient,
the stall should be darkened; in serious cases, and when the animal is
heavy, it may be advisable to use a sling; hot water fomentations are to be
preferred; the patient may be stood in a tub of hot water or heavy woollen
bandages that have been dipped in hot water and wrung, out as dry as
possible may be applied to the feet; the temperature of the water should be
no hotter than can be comfortably borne with the hands; the results of this
treatment depend on the faithfulness with which it is carried out; a
poultice of ground flaxseed should be applied to the foot at night, or
during the interval between the foot-baths. This treatment may be continued
until the acute inflammation has subsided.

If the animal is inclined to eat, it should be fed very little roughness
and grain. Soft feeds are to be preferred, and one quart of linseed oil
given as a physic. After a period of from ten days to three weeks,
depending on the tenderness of the feet, the wall at the toe should be
shortened, the sole trimmed if necessary, flat shoes rolled at the toe
placed on the feet, and the animal allowed to exercise a short time each
day in a lot or pasture. As the hoof grows rapidly, it is necessary to trim
it carefully every three or four weeks and replace the shoes. The wall at
the toe should be kept short, but excessive thinning of the sole should be
avoided.

The same line of treatment as recommended for the horse may be used for
laminitis in cattle. If marked diseased changes occur in the feet, it is
not advisable to attempt the treatment of chronic laminitis, unless it is
in valuable breeding animals.


QUESTIONS

1. Give a general description of the foot.

2. State the nature and causes of side-bones.

3. What are the causes of navicular disease? Give symptoms and treatment

4. What are corns? Give the treatment.

5. Give the nature and treatment of quarter- and toe-cracks.

6. Give the symptoms and causes of laminitis.

7. Give lines of treatment to be followed in the different forms of
   laminitis.

8. How may laminitis be prevented?



CHAPTER XVIII

DISEASES OF THE HIND LIMB


FRACTURE OF THE ILEUM, "Hipped."--Fracture of the angle and neck of the
ileum may be classed among the common fractures in horses and cattle.
Fractures involving other parts of the pelvic bones are less common. Such
fractures are due to accidental causes, as striking the point of the haunch
on the door frame when hurrying through a narrow doorway and falling on
frozen ground.

Fractures of the _external angle_ of the ileum or point of haunch are
usually followed by displacement of the fractured portion. The same is true
of fractures of the _neck of the ileum_. The result is a deformity of the
quarter.

In making an _examination_ of these parts the examiner should see that the
horse is standing squarely on its feet, and then compare the conformation
of the two quarters. Fractures of either the external angle or the neck of
the ileum cause the quarter to appear narrow and low. A close examination
may enable the examiner to differentiate between the two fractures.
Fractures of the neck of the ileum can be recognized by manipulating the
part through the walls of the rectum or vagina.

The degree of lameness may vary. In some cases there may be no lameness
when the animal walks, but a slight degree of lameness may be noticed when
it trots. For several weeks after the injury the horse may be unable to use
the limb, but it may eventually make nearly a complete recovery.

Atrophy of the muscles of the hip or quarter (Fig. 44) should not be
mistaken for fractures of the ileum. This condition involves the heavy
gluteal muscles and may occur as a complication of azoturia, or a lameness
of the hind limb that is usually due to a spavin.

It is very seldom necessary to give fractures of the ileum any special
care. If the animal is very lame, it should be given a narrow stall, and
placed in a sling until it can support its weight on the limb. The same
treatment is indicated in cattle. It is not advisable to breed a mare that
has had the ileum fractured. The bony enlargement that results from the
union of the broken ends of the bone may interfere with the passage of the
foetus through the pelvic cavity and cause difficult parturition.

[Illustration: FIG. 44.--Atrophy of the muscles of the quarter.]

LUXATION OF THE PATELLA, "Stifle Out."--This is a common accident in horses
and mules. Young, immature animals are more prone to displacement of the
patella than when mature. The displacement is usually upward or outward.
Outward displacement is comparatively rare.

_The causes_ of "stifle out" may be described as follows: The patella or
knee-cap rests on a pulley-like articular surface belonging to the inferior
extremity of the thigh-bone. The external lip of this articular surface is
smaller than the internal lip. The patella is held in place from above by
the heavy muscles of the anterior region of the thigh, and from below, by
straight ligaments that attach it to the leg-bone. If the retaining
structures mentioned become relaxed, the patella may, when the limb is
extended, become so displaced as to rest on the superior portion of the
external lip. Laxness of the muscles and ligaments in young animals is a
predisposing factor. Hard work that tires the muscles and causes them to
become relaxed, strains, unusual movements, as kicking in the stable and
slipping, may cause this accident. Congenital displacement results from
imperfect development of the external lip of the trochlea. Such a deformity
subjects the animal to frequent luxations.

_The symptoms may vary_. The displacement may be first noticed when the
horse is backed out of the stall or turned quickly. A slight "hitch" in the
movement of the limb is noted, that is followed by more noticeable flexion
of the hock than normal. In case the luxation is more permanent, the horse
stands quietly with the affected leg held stiffly and extended backward.
When made to move forward, it hops on the well leg and carries the affected
one, or drags it on the toe. If both limbs are affected, the animal is
unable to move. The inability to move the limb is due to the patella
resting on the external lip of the pulley surface, and a locking of the
stifle- and hock-joint.

This accident is annoying, and in case the horse is subject to it should be
considered an unsoundness.

The following _treatment_ may be recommended: The luxation may be reduced
in the large majority of cases by backing or turning the animal. If this
does not reduce the displacement, a collar should be placed on the animal,
and a hobble strap fastened to the pastern of the involved limb. One end of
a long rope is tied to the collar, passed backward between the front limbs,
through a ring in the hobble and back over the outside of the shoulder and
under the collar. While an attendant pulls the limb a little forward with
the rope, the operator takes hold of the foot and attempts to flex the
limb, at the same time pushing inward on the patella. After reducing the
luxation it is advisable to tie the rope to the collar, so that the limb is
carried forward. This prevents the animal from throwing weight on the foot.
It may be advisable to tie the animal so that it can not lie down, if the
foot is to be left hobbled for a few days. A fly blister should be applied
to the front and outside of the stifle and the application repeated in two
or three weeks.

STRING-HALT.--This term is applied to a peculiar involuntary movement of
one or both hind limbs that is characterized by a sudden, purposeless
flexion of the hock-joint (Fig. 45). Horses that are slightly affected may
show this movement of the hind limbs when first exercised. Other horses may
be "string-halted" when backed, turned, walked, or trotted, and fail to
drive out of it. The cause of true "string-halt" is not known.

_The treatment recommended is surgical._ This consists in cutting the
tendon of the peroneus muscle. The seat of the operation is a little below
the hock and on the external face of the cannon.

[Illustration: FIG. 45.--String-halt.]

SPAVIN.--A spavin is a chronic inflammation of the articular faces of the
hock bones, ligaments and synovial membranes. The inflammation may result
in the formation of a bony enlargement on the inner surface of the region,
and a union between the small bones forming the lower portion of the hock,
and the upper extremities of cannon and lower hock bones (Figs. 46 and 47).

[Illustration: FIG. 46.--A large bone spavin.]

The _predisposing causes_ are of the greatest importance. A spavin is one
of the unsoundnesses of horses that may be transmitted to the offspring.
Young colts that have heavy bodies and are fed a fattening ration are
predisposed to it. Crooked hind limbs, small hocks and quarters that are
heavily muscled are predisposing factors. The _external causes_ are strains
caused by slipping, turning quickly, rearing, pulling heavy loads and
kicks. Horses three or four years of age if given work that favors hock
strain, such as excavating cellars, may develop a spavin.

[Illustration: FIG. 47.--Normal cannon bone and cannon bone showing bony
enlargement and lower hock bones united to superior extremity; this occurs
in bone spavin.]

_The symptoms_ or lameness are more characteristic than in most diseases of
the limb. At the very beginning of the inflammation, and sometimes for
several months afterward, the lameness is intermittent and disappears with
exercise. After a time it is permanent. It is characterized by a stiffness
of the hock. The extension of the hock is incomplete, the step is short and
quick, the animal "goes on its toe" and the wall or shoe at the toe shows
considerable wear. Because of the stiffness in the hock the animal raises
the quarter when the limb is carried forward. Turning toward the well side
may increase the lameness. The _spavin test_ may be of value in diagnosing
lameness. This consists in picking up the foot and holding the hock in a
flexed position for a few minutes. The foot is then dropped to the ground
and the animal moved off at a brisk trot. If the lameness is more marked,
it indicates that the seat is in the region of the hock. This test is of
greatest value in young animals. The bony enlargement can usually be seen
best if the examiner stands in front and to one side of the animal. The
hock should be observed from directly behind as well. The hocks of both
limbs should be compared, and the general conformations of the other joints
as well. This may prevent the examiner from mistaking rough hocks for
spavin enlargements or "a pair" of spavins for rough hocks. A bony
enlargement does not always accompany the lameness, and a spavin may be
present without the horse going noticeably lame.

[Illustration: FIG. 48.--Bog spavins.]

_The prognosis_ is always uncertain and should be guided somewhat by the
conformation of the limb, character of the work required of the animal,
position of the bony enlargement and the degree of lameness. The size of
the enlargement is changed very little by the treatment. Veterinarians
report recoveries in from fifty to sixty per cent of the cases treated.

_The object of the treatment_ is to destroy the inflammation and bring
about a union between the bones. The treatment recommended is
counterirritation and rest. The most satisfactory method of
counterirritation is firing followed by blistering. Following this
treatment, the horse should be placed in a stall and given no exercise for
a period of five or six weeks. It is sometimes advisable to repeat the
counterirritation if the results of the first firing are unsatisfactory.

BOG SPAVIN.--Bog spavin is an extensive distention of the capular ligament
of the hock-joint by synovia (Fig. 48). It is generally due to chronic
inflammation of the synovial membrane. This blemish or unsoundness is most
common in young horses. Thorough pin (Fig. 49) involves the sheath of the
large tendon only. (Compare Figs. 48 and 49.)

[Illustration: FIG. 49.--Thorough pin. Note the relation of the enlargement
to the tendon, and the freedom of the hocks from bog spavin.]

Certain conformations of the hock favor the development of bog spavin. This
is especially true of upright and "fleshy" hocks. Hard work may cause the
hocks to "fill" when followed by a brief period of rest. The common cause
is a sprain due to slipping and pulling heavy loads.

The _following symptoms_ may be noted: Lameness is not a common symptom of
bog spavin. If there is inflammation present or the articulation is
injured, lameness occurs. The soft swelling that characterizes the bog
spavin is most prominent toward the inside and front of the region. In the
upper portion or hollow of the hock, and on the inside and outside, there
may be a second enlargement. Smaller enlargements may be present in other
regions. All of the swellings feel soft, and pressure on any one of them
moves the fluid present in the others.

_The treatment_ is directed at the removal of the lameness. Acute
inflammation resulting from spavin may be relieved by cold applications and
rest. Chronic lameness should be given the same treatment as recommended
for bone spavin. The enlargement can be successfully removed in growing
colts by the repeated application of mild blisters. It may be necessary to
continue the treatment for several months. The removal of the enlargement
in adult horses by an operation is recommended. The _greatest caution_ is
required in performing this operation.

CAPPED HOCK.--All swellings on the point of the hock are termed "capped
hock." The swellings may be due to an injury to the skin and the
subcutaneous tissue, or more important structures may be involved, as the
subcutaneous bursa, the tendon, or the synovial bursa or sack.

Capped hock is _caused_ by the animal kicking in the stall or in harness,
shipping in freight cars and lack of bedding in the stall. Unless the
deeper structures are bruised and inflamed the animal shows no lameness.

_The character_ of the enlargement varies. When the injury is superficial,
the swelling feels firm, or pits on pressure. Later it may become more firm
and feel like a loose, thickened, fibrous cap for the hock. Soft,
fluctuating swellings are due to an inflammation of the bursa. Recent
injuries feel hot.

_The preventive treatment_ consists in hobbling the hind limbs of a horse
that kicks in the stable. This is usually necessary only at night. It may
be advisable to pad certain parts of the stall. Horses that are transported
in cars should be protected against injuries during transit by the use of
proper care and such arrangement of the animals in the car as may expose
them to the least injury. Recent injuries should be treated by the
application of cold and rest.

After the inflammation has subsided tincture of iodine or blisters may be
applied. The treatment of bursal enlargements is surgical. This consists in
opening the bursa, destroying the lining membrane of the cavity and
treating the part daily until healed. The operation must be performed
carefully, as there is danger of infection with irritating organisms. The
animal should be given complete rest until the part is healed. Tincture of
iodine may be applied to the enlargement that may remain after healing has
occurred. This should be continued daily until the skin becomes noticeably
irritated. The treatment may be repeated, if necessary, after an interval
of two weeks.

[Illustration: FIG. 50.--Curbs.]

CURB.--This term is applied to all swellings on the posterior border of the
hock (Fig. 50). Thickenings or enlargements in this region may involve a
variety of structures. Thickening of the skin, tendons and sheath may
occur. The large ligament that extends from the posterior border of the
bone that forms the summit of the hock to the external splint bone, and
acts as a stay for the point of the hock, is the structure usually involved
in curb.

Faulty conformation is a _predisposing cause_. A narrow base weakens the
hock at this point, and the extreme length of the bone that forms its
summit gives the powerful muscles attached to it greater leverage than in a
well-conformed hock. This results in strain to the ligament at the
posterior portion of the region.

_The exciting causes_ are strains resulting from jumping, slipping,
rearing, heavy pulling and bruising of the part.

_In examining the hock_ for curb it is necessary to stand to the side and
note the profile of the posterior border. Excessive development of the head
of the external splint bone should not be mistaken for curb. As viewed from
the side, the posterior border of the hock should appear straight.

The curb appears as a swelling on this straight line. It varies in size. A
recent curb is usually hot and firm, or may feel soft if enlargement is
formed by fluid, hard if formed by bone. Lameness seldom occurs, but if
present, resembles spavin lameness.

_The preventive treatment_ consists in selecting for breeding, animals that
have strong, straight hocks, and using the necessary care in handling and
working horses. It is not uncommon for young horses at the time they are
broken to harness to develop a curb. This may be prevented to a large
degree by careful handling. At the beginning of the inflammation the
application of cold and hand rubbing is indicated. After the inflammation
has subsided tincture of iodine or blisters should be applied. Rest is a
necessary part of the treatment early in the inflammation. If the lameness
does not respond to the above treatment, it should be treated the same as
for bone spavin.


QUESTIONS

1. Describe the different fractures of the ileum and give treatment.

2. Describe string-halt lameness and give treatment.

3. What is bone spavin? Describe spavin lameness.

4. Give the causes and treatment of bog spavin.

5. Give the causes and treatment of capped hock.

6. Give the causes and treatment of curb.



PART III.--THE TEETH



CHAPTER XIX

DETERMINING THE AGE OF ANIMALS


[Illustration: FIG. 51.--Head of young horse with bone cut away, and
showing position and size of teeth.]

GENERAL DISCUSSION.--The teeth are the passive organs of digestion. They
are hard organs, implanted in the superior and inferior jaws in the form of
a long and narrow arch that is open posteriorly. The free portions of the
teeth project into the mouth, and present sharp or roughened table surfaces
for the crushing and tearing of food. In solipeds and ruminants the arch is
interrupted on each side by the inter-dental space or bars (Fig. 51). The
teeth that form the middle and anterior portion of the arch are termed
incisors (Fig. 52). Posterior to the incisors are the canines or tusks, and
forming the arms of the arch are the molar teeth. Animals have two sets of
teeth, temporary and permanent. The following table gives the number of the
different kinds of temporary and permanent teeth.

               Temporary Teeth            Permanent Teeth
           Incisors Canines Molars    Incisors Canines Molars

Solipeds       12             12         12       4      24
Ox              8             12          8       0      24
Sheep           8             12          8       0      24
Hog            12             12         12       4      24

The tusks or canine teeth are not always present in the female. Ruminants
do not have upper incisor teeth.  The temporary teeth are erupted either
before or within a few days to a few months after birth. The eruption of
the permanent teeth and the replacement of the temporary teeth occur at
different periods up to the age of four and one-half years (Fig. 53). It is
well to keep the following table of dentition in mind when examining the
mouths of animals for the purpose of determining their age.[1]

                    Horses              Cattle                Hogs
Teeth        Temporary Permanent  Temporary Permanent  Temporary Permanent

Incisors:              yrs. mos.           yrs. mos.               mos.
  Centrals   At birth   2    6    At birth  1    8     At birth,   12
                                                        or 3-4
                                                        weeks
  First      4-6 wks.   3    6    At birth  2    9     8-12 wks.   18
    laterals
  Second                          5-12 days 3    6
    laterals
  Corners    6-9 mos.   4    6   12-18 days 4    6     At birth     9
Molars:
  First      At birth   2    6    At birth  2    6     7 weeks      5
  Second     At birth   2    6    At birth  1    6     8-28 days   14
  Third      At birth   3    6    At birth  3          8-28 days   13
  Fourth              10-12                 1    6                 13
  Fifth                 2                   2                       5
  Sixth                4-5                  2    6                  9
  Seventh                                                          18
Canines or             4-5                                          9
  tusks

IN DETERMINING THE AGE of the different domestic animals by the development
and appearance of the teeth, most of the attention is given to the lower
incisor teeth. Up to the fifth year, the age of the horse or ox can be
easily determined by the eruption and replacement of the incisors.

At _one year_ of age the colt has a fully developed set of temporary
incisors. The ruminant's incisors at this age all show wear.

_The two-year-old colt_ shows a well-worn set of incisor teeth, and the
ruminant at this age has replaced the nippers or centrals.

_The third_, _fourth_ and _fifth years_ are indicated by the replacement of
the temporary nippers, dividers and corners in the horse, and the first and
second dividers and corner teeth in ruminants.

[Illustration: FIG. 52.--Longitudinal section of incisor tooth: cup;
cement; enamel; ivory; and pulp cavity.]

In the horse the permanent nippers are full grown and in wear at _three
years_ of age; the permanent dividers are full grown and in wear at _four
years_ of age; and the permanent corners are full grown and in wear at
_five years_ of age. The table surfaces of the incisor teeth of a
five-year-old horse show different degrees of wear. At this period in the
animal's age, the nippers have been in wear two years, the dividers one
year, and the corners are beginning to show wear. In ruminants, all of the
chisel-shaped table surfaces of the incisors show considerable wear when
the animal is five years old.

After the animal has a full set of permanent teeth, we judge the age by the
degree of wear or the appearance of the table surfaces of the incisors,
their shape, the angle with which they meet and the general appearance of
the head.

[Illustration: FIG. 53.--Cross-section of head of young horse showing
replacement of molar tooth.]

There are several different factors that may cause the wear on the teeth,
and the appearance of their table surfaces to vary in the different
individuals. The two factors that are of the most importance are the
quality of the teeth and the character of feed. Soft teeth wear more
quickly than hard teeth, and the teeth of horses that feed over closely
cropped and sandy pastures wear rapidly because of the dirt and grit
present on the short grass. This variation in the wear is of little
importance to the person who must judge the age of a horse that he expects
to purchase by the condition of the teeth. In reality, a horse is just as
old as the wear on the teeth and his general appearance indicate. In order
to stand severe work the animal must be able to masticate the feed, and
prepare it for digestion in the stomach and intestines. The degree of wear
on the molar teeth may be indicated by the wear on the incisors. The
general condition of the horse and his ability to stand hard work depend
very largely on the condition of the table surfaces of the molars.

It is very difficult to judge the age of horses that have deformed mouths
or that are in the habit of crib-biting, because of the irregularity in the
wear of the incisors.

When examining the teeth for the purpose of determining the horse's age,
the shape of the incisors, the angle with which they meet and the
appearance of their table surfaces should be observed. The teeth of young
horses show more or less yellowish cement. At about seven years of age the
anterior faces of the teeth are usually white, later a yellowish color. The
teeth of middle-aged horses may be long, and in aged animals, narrow and
short. The incisors meet at a more acute angle in old than young horses.

_The free portion of the incisor_ tooth is flattened from before to behind.
At the level of the gums its two diameters are about the same, but the
portion of the tooth imbedded in the jaw bone is flattened from side to
side. As the tooth becomes worn off, the length of the free portion is
maintained by a pushing out of the tooth, and a corresponding shortening of
the portion that is fixed or imbedded in the jaw.

_The table surface of the unworn incisor_ tooth is covered with enamel, and
in the middle portion the enamel forms a deep cup. After the tooth has
become worn the margin of the table portion is then limited by a ring of
enamel. This is termed the encircling enamel ring. The central portion of
the table shows a second ring, the central enamel ring, that limits the cup
margin (Fig. 54).

[Illustration: FIG. 54.--Transverse section of incisor tooth: peripheral
cement; peripheral enamel; ivory; central enamel; and central cement.]

_As the table surface_ represents a cross section of the tooth, its
appearance and shape will then depend on the portion of the tooth that it
represents. From year to year, there is a gradual shortening in the lateral
diameter, and an apparent increase in the diameter from before to behind.
These changes in shape are from a long, narrow table surface to an oval,
from oval to circular and from circular to triangular (Fig. 55). As the
original free portion of the tooth wears off, the cup becomes shallow and
smaller until the remnant is represented by a mere dot of enamel that
finally disappears from the posterior portion of the table. After the cup
has moved from the central portion of the crown and occupies a more
posterior position, the dental star, which represents a cross section of
the pulp cavity, puts in its appearance. It first takes the form of a brown
or dark streak, and later a circular dark spot which gradually increases in
size with the wear on the tooth and the age of the animal.

[Illustration: FIG. 55.--Table surfaces of nippers at different ages: four
years; six years; nine years, and fifteen years of age.]

The following changes in the shape and appearance of the incisor teeth of
the average horse occur in the different years. Unless otherwise mentioned,
the statements made regarding the appearance and wear on the table surfaces
apply to the lower incisor teeth.

SIX YEARS.--The table surfaces form the most accurate guide. The cups of
the nippers tend to an oval form. The corner teeth have been in wear one
year at this time. The cup is deep and the posterior margin may show little
wear. It is not uncommon to meet with corners that possess irregularly
developed tables, and have cups with posterior margins that are thin and do
not come into wear until later. For this reason, it is not best to depend
on the appearance of the corner teeth alone.

SEVEN YEARS.--The teeth are usually whiter than the previous year. The
profile of the upper corner teeth shows a notch in the posterior portion of
the table surface. This is due to the superior corners overhanging the
inferior corner teeth posteriorly, resulting in this portion not wearing
away. This notch is sometimes slightly in evidence the previous year. The
cups in the corners are smaller and the worn surface larger than at six.
The nippers show oval table surfaces and the dividers are beginning to take
on this shape. The shifting of the cups toward the posterior portion of the
tables of the nippers and dividers is noticeable.

EIGHT YEARS.--As viewed from the side, the profile of the teeth shows a
very noticeable increase in the obliquity with which they meet. The
posterior borders of the corners show considerable wear. The notch in the
superior corners is still present, but as the teeth come more nearly in
apposition it may begin to disappear. All of the inferior tables are level.
The nippers and dividers are oval in shape, and the cups have become
decidedly narrow. The nippers show a well-defined dark streak just in front
of the cups. This is the beginning of the dental star.

NINE YEARS.--The appearance of the table surface is more characteristic at
this time than the previous year. The cups are less prominent and the
plainness or smoothness of the inferior table is more noticeable. The
nippers are round, the cups triangular and the dark streak narrower and
more distinct than the previous year. The dividers are becoming round and
the corner teeth are oval.

TEN YEARS.--The teeth are more oblique than in the eight-year-old and
nine-year-old mouth. The table surfaces of the inferior nippers are
decidedly rounded, the cups are small, triangular and situated well toward
the posterior borders. The dark brown streak or dental star is situated in
the central portion of the nippers and dividers. The tables of the dividers
are round.

ELEVEN YEARS.--The tables of the corner teeth are rounded. The dark streak
or dental star is present in all of the teeth, and the remnants of the cups
appear as small rings or spots of enamel near to the posterior borders of
the tables. The notch in the superior corners may reappear at this time.

TWELVE YEARS.--The profile of the teeth when viewed from the side is quite
oblique. The table surfaces of all the incisors are round. But a trace of
the cup remains in the inferior incisors. The head of the animal is
beginning to show age. The inferior border of the jaw bone appears
narrower, or sharper than in the young horse.

THIRTEEN YEARS.--All of the specks of enamel or the remnants of the cups
are gone from the lower incisors. A larger notch may be present in the
upper corner teeth than at twelve. The tables of the inferior nippers are
becoming triangular and show a small, dark spot or dental star.

FOURTEEN YEARS.--The tables of the inferior nippers are triangular, and the
dental star appears as a dark round spot in both the nippers and dividers.

FIFTEEN YEARS.--The angle with which the teeth meet is greater than at
twelve, the teeth are smaller and dental stars are represented by dark
round spots in all of the inferior incisors. The tables of the nippers and
dividers are triangular.

SEVENTEEN YEARS.--All of the tables of the lower incisor teeth are
triangular. The teeth are narrower and smaller than at fifteen. The profile
of the incisors, viewed from the side, is quite angular. The dental stars
are prominent.

NINETEEN YEARS.--All of the signs of the seventeen-year-old mouth are more
prominent. The cups have usually disappeared from the upper incisors.

[Footnote 1: This table is from dentition tables given in "Age of the
Domestic Animals," by Huidekoper.]


QUESTIONS

1. Name the different kinds of teeth; state the arrangement and number.

2. How is the age of an animal determined?

3. Give the time of replacement of the temporary incisor teeth.

4. How is the age of the animal determined between the fifth and ninth
   years?

5. What changes in the appearance of the table surfaces occur between ten
   and fifteen years of age?



CHAPTER XX

IRREGULARITIES OF THE TEETH


Parrot-mouth, Lantern-jaw and Scissor-mouth.--The common deformities of the
jaw and teeth are the overshot or parrot-mouth, the undershot or
lantern-jaw, and the scissor-mouth. These different deformities result in
unequal wear on the table surfaces of the incisors and molars. In both the
overshot and undershot jaws, the incisor teeth become abnormally long. In
the _parrot-mouth_, the wear occurs on the posterior face of the superior
and the anterior face of the inferior incisors, the teeth becoming worn to
rather a sharp edge, depending on the degree of the deformity. In the
_lantern-jaw_, the wear occurs on the posterior face of the lower and the
anterior face of the superior row of incisors, the teeth taking on somewhat
the same shape as the parrot-mouth. The greater the deformity and the older
the horse becomes, the more difficult it is for the animal to feed or
graze on pasture.

In all horses, the two rows of molar teeth are wider apart in the superior
than in the inferior jaw. This results in the external border of the tables
of the superior row of molars becoming longer, or projecting further
downward than the internal border. The wear on the table surfaces of the
inferior row of molars is just the opposite of the superior row. In the
_scissor-mouth_ the wear takes place largely on the internal face of the
superior and the external face of the inferior row of molars. The teeth
become worn to more or less of a blunt cutting edge, and after a time the
molars come together somewhat like the jaws of a pair of scissors. A horse
with a badly deformed scissor-mouth is unable to grind the feed, and unless
given special care, suffers severely from innutrition.

_The treatment_ of deformed mouths consists in removing the irregular or
unworn portion of the teeth by means of the tooth float and cutters. This
attention should be given early before the free portion of the tooth has
become excessively long and irregular. This should be followed by dressing
the teeth every six or twelve months.

SHARP LATERAL BORDERS ON THE MOLAR TEETH.--This is a very common condition
in horses. The external border of the superior and the internal border of
the inferior row of molars wear away slowly, and sometimes become quite
sharp. This is objectionable because the sharp points lacerate the mucous
membrane of the cheek and tongue, and the mastication of the feed is
seriously interfered with.

This condition is _caused_ by an excessive difference in the width of the
jaws, unusually prominent ridges of enamel on the external face of the
superior molars, and any conditions that may limit the movements of the
jaw.

The following _symptoms_ may be noted. The animal has difficulty in
masticating the feed because of injury to the cheeks or tongue by the sharp
points of enamel. This condition may be indicated by holding the head to
one side. Salivation is usually present. Acute indigestion and innutrition
may occur.

By examining the teeth, their condition can be determined. The sharp
borders may be removed by dressing or floating the teeth. It is advisable
in the majority of horses to float the teeth at least once in every twelve
months.

IRREGULARITIES IN THE TABLE SURFACE OF THE MOLAR TEETH.--Horses eight years
of age or older frequently have irregular molars (Fig. 56). This is due
very largely to the difference in the quality of the teeth. The harder
molars do not wear off as rapidly as the softer ones. This results in the
table surfaces of the rows of molars becoming wavy or step-like in outline.
Sometimes the first or sixth molar overhangs or projects beyond the
corresponding tooth of the opposite jaw. When this occurs, the over-hanging
portion may become long and sharp. A molar tooth becomes excessively long
if the opposite one is decayed or removed.

_The symptoms_ are very much the same as when the borders of the molars
are sharp.

[Illustration: FIG. 56.--Teeth showing uneven wear occurring in
old horses.]

_The treatment_ consists in levelling the tables as frequently as necessary
by cutting off the longer projections, and removing the sharp edges with a
tooth float.

SMOOTH MOUTH.--In old age the tables of the molar teeth may become so
smooth that the horse cannot grind or masticate the feed. When all of the
molars are in this condition, a rubbing sound may be noted when the animal
is masticating hay. After attempting to chew the hay, it may be dropped
from the mouth. Innutrition always occurs.

_The treatment_ consists in feeding chops and soft feeds.

DENTAL DISEASES.--Inflammation of the alveolar periosteum is a common
dental disease in domestic animals. This is an inflammation of the alveolar
dental membrane that fixes the tooth in the tooth cavity.

Injuries to the gums and cracks or fissures in the tooth are the _common
causes_. Caries or tooth decay is not uncommon. The predisposing factor is
a poor quality of enamel and dentine. The process of decay is assisted by
microorganisms.

The _early symptoms_ may escape notice. Slobbering, masticating on one
side, holding the head to one side, retained masses of food in the mouth
and a disagreeable odor frequently occur. Caries may be indicated at first
by a dark spot on the table of the tooth, later by a cavity. In horses,
inflammation of the alveolar membrane results in a bony enlargement on the
side of the face if the superior molar is involved. A swelling of the jaw
and fistula may result if a lower molar is involved (Fig. 57).

[Illustration: FIG. 57.--Fistula of jaw. This condition was the result of
neglected treatment of decayed teeth.]

_The treatment_ consists in the prompt removal of the tooth. This is more
difficult in young animals than it is in the middle-aged or old. Unless the
tooth is already loosened it may be necessary to remove it by trephining.


QUESTIONS

1. Describe the appearance of the teeth in an overshot or undershot jaw.

2. Describe the appearance of sharp molar teeth; a scissor-mouth.

3. What are the causes of decayed teeth?



PART IV.--SURGICAL DISEASES



CHAPTER XXI

INFLAMMATION AND WOUNDS


Inflammation is a pathological condition of a tissue, characterized by
altered function, disturbance of circulation, and destructive and
constructive changes in the irritated part. Heat, redness, swelling, pain
and disturbed function are the symptoms which characterize inflammation.

_The changes in the circulation_ occurring in inflammation are as follows:
(1) An increase in the rate of the blood-flow through the blood-vessels of
the part and their dilation; (2) diminished velocity followed by the
blood-flow becoming entirely suspended; (3) following the retardation or
suspension of the blood stream, white blood-corpuscles accumulate along the
walls of the small veins and capillaries; (4) white and red
blood-corpuscles migrate from the vessels into the neighboring tissue, and
blood-serum transudes through the walls of the vessels, forming the
inflammatory swellings. The red blood-cells do not escape from the
blood-vessels in any numbers unless the walls of the blood-vessels become
injured or badly diseased.

_The causes of inflammation_ may be grouped under the following heads:
mechanical, chemical, thermic and infectious. The _mechanical_ or
_traumatic causes_ commonly produce inflammation in domestic animals. These
are kicks, strains of tendons, ligaments or muscles and wounds.
Inflammation originating from injuries very frequently changes to an
infectious form, through the infection of the part by bacteria. Bruised
tissue may become infected with pus-producing organisms, and an abscess or
local swelling form. All accidental wounds in domestic animals become more
or less infected by irritating microorganisms.

The following _symptoms_ occur in local inflammation. Increased heat in the
part is an important symptom. It is due to the increased blood-flow to the
part. Because of the pigmented, hairy skin of domestic animals, redness is
of little value in locating superficial inflammation. Swelling is a
valuable local symptom. It is produced by the inflammatory exudates. Pain
results from the pressure on the sensory nerves by the inflammatory
swelling. For example, the laminae of the foot are imprisoned between the
horny wall and the pedal bone. This structure is well supplied with sensory
nerves, and when it becomes inflamed and swollen, the tissues are subject
to severe pressure and the pain is severe. Inflammation of a tendon results
in lameness; of the udder, in suspension of milk secretions; and of the
stomach by interference with digestion of the feed. Such symptoms may be
grouped under the head of disturbed functions.

_The character of an inflammation_ is largely modified by the nature of the
tissue in which it occurs. A serous inflammation is characterized by
serous, watery exudates. This form occurs in the serous membranes, mucous
membranes and skin. Blisters on the skin and inflammation of bursae (capped
hock and shoe boil) are examples of this type. Sero-fibrinous
inflammations, such as occur in pleurisy and peritonitis, are common.
Chronic inflammation commonly results in new formations of tissue, and it
is named according to the character of the new tissue formed, as ossifying,
adhesive, and fibrous inflammation. Pus-forming bacteria produce
suppurative inflammation. Such diseases as tuberculosis, glanders and
hog-cholera are specific inflammations. Specific infectious diseases may be
classed as generalized inflammation, as they usually involve the entire
body.

Inflammation terminates in resolution when the serum is reabsorbed by the
blood-vessels and lymphatics, the living blood-cells find their way back
into the circulation and the dead cells disintegrate and are taken up by
the vessels. The time required for the tissues to return to the normal
varies from a few hours to several weeks. An acute inflammation may end in
the chronic form. This may then terminate in new formations, such as
adhesions, fibrous thickenings and bony enlargements. Severe inflammation,
especially if localized and superficial, may result in death of the part or
gangrene.

The following _treatment_ is recommended: The cause of the irritation to
the tissue must be removed. It is very essential that the part be rested.
The necessary rest may be obtained in different ways. Inflamed tendons,
ligaments, and muscles may be rested by placing the animal in a sling,
standing it in a stall, or fixing the part with bandages. Rest of the
stomach or intestinal tract may be obtained by feeding a light diet, or
withholding all feed. Comfortable quarters, special care and dieting the
animal are important factors in the treatment of inflammation.

The agents used in the treatment of superficial and localized inflammation
are _heat, cold, massage_ and _counterirritation_. _Heat_ is indicated in
all inflammations, excepting when of bacterial origin. It stimulates the
circulation and reabsorption of the inflammatory exudates, and by relaxing
the tissues helps greatly in relieving pain. _Cold_ is more effective in
the highly acute and septic (suppurative) inflammation. Its action consists
principally in the contraction of the dilated blood-vessels. Continuous
irrigation of the part with cold water is the most satisfactory method of
applying cold. _Massage_ is a very important method of treating superficial
inflammation. Mild, stimulating liniments are usually used in connection
with hand-rubbing or friction. Chronic inflammation is usually treated with
_counterirritants._ Blistering and firing are the most important methods
of treatment. Such counterirritation makes possible the absorption of the
inflammatory exudates by changing the chronic inflammation to the acute
form.

WOUNDS.--A wound, in the restricted sense that the term is commonly used,
includes only such injuries that are accompanied by breaks or divisions of
the skin and mucous membrane. It is usually an open, hemorrhagic injury.

If the tissues are severed by a sharp instrument and the edges of the wound
are smooth, it is classed as an _incised_ or _clean-cut wound_. This class
is not commonly met with in domestic animals outside of operative wounds.

When the tissues are torn irregularly, the injury is classed as a
_lacerated wound_. A barb-wire cut is the best example of this class.

A _contused wound_ is an injury caused by a blunt object. Such injuries may
be divided into superficial and deep. Superficial-contused wounds may be an
abrasion to the skin or mucous surface. Deep-contused wounds may be
followed by loss of tissue or sloughing, and may present irregular, swollen
margins. Such injuries are commonly caused by kicks.

_Punctured wounds_ are many times deeper than the width of the opening or
break in the skin or mucous membrane. This class is produced by sharp
objects, such as nails, splinters of wood, and forks.

Sometimes, wounds are given special names, as gun-shot, poisoned, and open
joint, depending on the nature of the cause and region involved.

Bleeding or hemorrhage is the most constant symptom. The degree of
hemorrhage depends on the kind, number and size of the blood-vessels
severed. In arterial hemorrhage, the blood is bright red and spurts from
the mouth of the cut vessel. In venous hemorrhage, the blood is darker and
flows in a continuous stream. In abrasions and superficial wounds capillary
hemorrhage occurs. Death may follow severe hemorrhage. Weak pulse,
general weakness, vertigo, loss of consciousness and death may result if
one-third of the total quantity of blood is lost. Unthriftiness and general
debility may follow the loss of a less quantity of blood.

The following _symptoms_ may be noted in the different kinds of wounds: The
sensitiveness to the pain resulting from accidental or operative wounds
varies in the different individuals and species, and in the kind of tissue
injured. Injuries to the foot, periosteum, skin and mucous membrane are
more painful than are injuries to cartilages and tendons. The appearance of
the wound varies in the different regions and the different tissues.

If the tissues are badly torn or bruised, swelling and sloughing may occur.
If the wound is transverse to the muscular fibres, it gaps more than when
parallel to the muscle. When infected by irritating organisms, open and
punctured wounds (Fig. 58) become badly swollen, discharge pus freely and
heal slowly with excessive granulations. Wounds involving tendons, bursae
and closed articulations become swollen and discharge synovia. Wounds
involving muscles, tendons and bursae usually cause lameness, and when
involving a special organ, interfere with, or destroy, its function.
Extensive or serious wounds may be followed by loss of appetite. An
abnormal body temperature and other symptoms characteristic of the
different forms of blood poisoning may follow infection of the injured
tissues by certain germs.

[Illustration: FIG. 58.--A large hock caused by a punctured wound of the
joint.]

The rapidity with which wounds heal depends upon the kind of tissue injured
and the amount to be replaced, the degree of motion in the part, the kind
and degree of infection and irritation and the general condition of the
animal. In general, skin and muscles heal rapidly, tendons slowly,
cartilages unsatisfactorily and nerve tissue very slowly. Healing is
greatly interfered with by movement of the part (Fig. 59). The more nearly
the part can be fixed or rested, the more quickly and satisfactorily does
healing occur. Irritation by biting, nibbling, licking, bandaging, wrong
methods of treatment and filth retard healing and may result in serious
wound complications. An animal in poor physical condition, or one kept
under unfavorable conditions for healing, cannot recover from the injury
rapidly or satisfactorily.

[Illustration: FIG. 59.--A large inflammatory growth following an injury to
the front of the hock.]

WOUND HEALING.--The following forms of healing commonly occur in wounds:
First and second intention; under a scab, and by abnormal granulation.

_Healing by first intention_ occurs when the wound is clean cut and there
is very little destruction of tissue, and when there is no suppuration or
pus formation. The blood and wound secretions cause the edges of the wound
to adhere. After a few days or a week the union becomes firm. Very little
scar tissue is necessary in this form of healing.

_Healing by second intention_ is characterized by pus formation and
granulation tissue. After the first day, the surface of the wound may be
more or less covered by red, granular-like tissue. Later this granular
appearance is modified by an accumulation of creamy pus and swelling of the
part, and finally scab formation and contraction of the new scar tissue.

Abrasions and superficial wounds usually _heal under a scab_. The scab is
formed by the blood and wound secretions. This protects the surface of the
wound until finally the destroyed tissue is replaced by the granulations,
and the skin surface is restored.

_Abnormal granulation_ is not an uncommon form of healing in domestic
animals. Mechanical and bacterial irritation causes the injured tissue to
become swollen and inflamed. In such a wound, excessive and rapid
granulation occurs, the new tissue piling up over the cut surfaces and
appearing red and uneven. This is termed excessive granulation or "proud
flesh." This tissue may refuse to "heal over," or the scar may be large,
prominent and painful. Abnormal tissue (horny or tumor-like) may sometimes
form.

WOUND TREATMENT.--Wounds in domestic animals are frequently allowed to heal
without special care or treatment. This is unfortunate. The careful and
intelligent treatment of wounds would greatly decrease the loss resulting
from this class of injuries. The method of treatment varies in the
different kinds of wounds.

_The first step_ in the treatment is to _check the haemorrhage_. Heat,
ligation, pressure and torsion are the different methods recommended.
Bathing the wound with hot water (115\260-120\260 F.) is a satisfactory
method of controlling haemorrhage from small blood-vessels. Ligation and
torsion of the cut end of large blood-vessels should be practised.
Pressure over the surface of the wound is the most convenient method of
Controlling haemorrhage in most cases. Whenever possible, the part should
be bandaged heavily with clean cheese cloth or muslin. Before applying
the bandage, it is advisable to cover the wound with a piece of sterile
absorbent cotton that is well dusted with boric acid. Hemorrhage from
wounds that cannot be bandaged may be temporarily stopped by pressure
with the hand, or, better, by packing the wound with absorbent cotton
and holding this in place with sutures. This should be left in place for
a period of twelve or thirty-six hours, depending on the extent of the
haemorrhage and character of the wound.

The next step is the _preparation of the wound for healing._ The injured
tissues should be carefully examined for foreign bodies such as hair, dirt,
gravel, slivers of wood and nails. The hair along the margins of the wound
should be trimmed, and all tissue that is so torn and detached as to
interfere with healing cut away. Drainage for the wound secretions and pus
should be provided. The advisability of suturing the wound depends on its
character and location. A contused-lacerated wound should not be closed
with sutures unless it is clean and shows no evidence of sloughing. A badly
infected wound should be left open unless satisfactory drainage for the pus
and wound secretions can be provided. Wounds across the muscle and in parts
that are quite movable should not be sutured.

_The after-treatment_ consists in keeping the animal quiet, if the wound is
in a part that is quite movable, and preventing it from biting, licking or
nibbling the injury. Wounds in the region of the foot become irritated with
dirt and by rubbing against weeds and grass. This makes it advisable to
keep the animal in a clean stall until healing is well advanced. Local
treatment consists in keeping the wound clean by washing the part daily, or
twice daily, with a one per cent water solution of a cresol disinfectant.
Liquor cresolis compositus may be used. It is sometimes advisable to
protect the granulating surface against irritation by dusting it over with
a non-irritating antiseptic powder, or applying a mixture of carbolic acid
one part and glycerine twelve parts. After the wound shows healthy
granulations longer intervals should lapse between treatments.

In poorly cared for, and badly infected wounds, the part may become badly
swollen, the granulations pile up and the wound refuse to "heal over." It
may be advisable in such cases to cut away the excessive granulations and
stop the haemorrhage by cauterization with a red-hot iron, or by
compression. Unhealthy granulations may be kept down by applying caustic
occasionally.

ABSCESS.--This is an accumulation of pus in the tissues. It may be due to a
severe bruise or contusion that is followed by the infection of the part
with some of the pus-producing bacteria. Abscesses occur in certain
infectious diseases. In strangles, the disease-producing organism may be
carried to different regions of the body by the circulatory vessels. This
may result in a number of abscesses forming in the different body tissues.

The following _forms of abscess_ are recognized: hot and cold, superficial
and deep, simple and multiple. The hot is the acute, and the cold the
chronic abscess. The terms superficial and deep allude to the relative
position of the abscess, and simple and multiple to the number present.

An abscess may first appear as a hot, painful swelling. If superficial, the
skin feels tense and the contents fluctuate when pressed on. Later the
fever subsides and no pain may occur when the abscess is pressed upon. Deep
abscess may not fluctuate.

_The treatment_ consists in converting the abscess into an open wound
whenever possible. The incision should extend to the lowest part of the
wall, so as to insure complete drainage. A cold abscess in the shoulder
region may become lined by a layer of tissue that retards healing. In order
to hasten the healing process, it may be necessary to remove this. Until
granulation is well advanced, the abscess cavity should be irrigated daily
with a one per cent water solution of liquor cresolis compositus, or a one
to two thousand water solution of corrosive sublimate. The surface of the
skin in the region of the abscess should be kept clean.

[Illustration: FIG. 60.--Fistula of the withers, showing the effect of
using caustics carelessly.]

FISTULOUS WITHERS AND POLL EVIL.--These terms are applied to swellings,
blood tumors, abscesses and pus fistulae that may be present in the region
of the poll and withers (Fig. 60). Pus fistula is the characteristic lesion
present, and it is the result of a suppurative inflammation of the tissues
in the region. The abscess cavity or cavities are usually deep, and may
involve the ligaments and vertebrae.

Bruises or contusions are the most _common causes_. The prominence of these
regions predisposes them to injury in the stable, or when rolling on rough
or stony ground. Bites and bruises to the withers resulting from other
horses taking hold of the region with the teeth, or striking the part
against a hard surface, are frequent causes.

_The treatment_ is both preventive and surgical. All possible causes should
be investigated. This is of special importance on premises where several
horses develop fistulous withers and poll evil. If the cause then becomes
known, it should be removed.

_The surgical treatment_ consists in opening up the different abscess
cavities, providing complete drainage for the pus and destroying the tissue
that lines the walls of the cavities. Horses that are prone to rub the
region should be prevented from doing this, as such irritation retards
healing. Autogenous bacterins should be used in addition to the surgical
treatment. A pus fistula should heal from the bottom, and if the opening
becomes closed, drainage should be re-established. The daily treatment is
the same as recommended for abscesses. Excessive cutting and destruction of
the tissues with caustic preparations result in scarring and deformity of
the part. Such radical lines of treatment should be discouraged. We should
not delay the surgical treatment of abscesses in the regions of the poll
and withers.


QUESTIONS

1. Name and describe the different forms of inflammation.

2. Give the causes and treatment of inflammation.

3. Name and describe the different methods by which wounds heal.

4. Describe the treatment of wounds.

5. What are the causes of an abscess? Give the treatment.

6. What are the causes of fistula and poll evil? Give the treatment.



CHAPTER XXII

FRACTURES AND HARNESS INJURIES


FRACTURES.--Broken bones or fractures are not uncommon in domestic animals.
In the horse, the bones of the leg, forearm, foot, and spine are the most
commonly broken. In the dog the largest percentage of fractures occurs in
the superior regions of the limbs.

Fractures may be classified as _simple_ and _compound, complete_ and
_incomplete, comminuted_ or _splinter_. In the simple fracture the skin
over the region escapes injury, but in the compound fracture the skin is
broken and the ends of the broken bone may protrude through it. The terms
complete and incomplete are used in describing fractures in which the ends
of the bones are not attached to each other, or partially so. In the
comminuted fracture the bone is broken into a number of pieces. There are a
number of other terms that may be used in designating the different kinds
of fractures, such as double, when both bones in the region are broken, and
oblique, transverse and longitudinal, depending on the direction of the
break.

_The causes_ of fractures may be divided into external or mechanical, and
internal. Fractures may result from kicks, blows, muscular strain and
contusions. Abnormal fragility due to disease, extreme youth and old age
are the internal predisposing factors.

_The symptoms_ are crepitation, abnormal movement and deformity of the
part. Abnormal movement of the part and inability to support weight occur
in fractures of the bones of the limbs. Crepitation or a grinding, rubbing
sound due to the movement of the ends of the broken bones on one another
occurs when the part is moved or manipulated with the hands. Pain, swelling
and injury to the skin are other local symptoms. The new tissue or bone
callus is formed by the bone-forming cells in the deeper layer of the
periosteum and bone-marrow.

_The prognosis is unfavorable._ The larger percentage of fractures in
domestic animals are incurable, or make an unsatisfactory recovery. This is
due to careless treatment, the character of the fracture and the inability
to fix the ends of the broken bone. Fractures in young and small animals
usually heal quickly. Individuals that are healthy and vigorous usually
make a speedy recovery. Fractures heal very slowly in the aged. Compound
and comminuted fractures are impossible to treat in the larger percentage
of cases.

_The treatment_ consists in fixing the broken bone or bones in a normal
position by means of bandages and splints. If this is not practised, the
surrounding tissues become injured by the broken ends of the bone, and the
fracture may become so complicated as to render treatment useless. Motion
retards or prevents the repair of the break.

However, fractures of the ribs, pelvic bones and sometimes long bones that
are well covered by heavy muscles heal naturally or in the absence of any
means of retention.

_Bandaging_.--The attendant must use good judgment in devising means of
fixing the broken bone, and in holding it in its natural position. Whenever
possible, a plaster bandage should be used. This must not be made too
heavy, and it is very necessary to adjust it properly, so that it will stay
in place and not become too tight or too loose. When applied to the limb,
the bandage should extend as far down as the hoof, and some distance above
the break. This is necessary in order to keep it from slipping down and
becoming too loose. A soft bandage should be applied first in order to
equalize the pressure from the plaster cast and protect the skin. Wooden
splints are not very satisfactory agents for the treatment of fractures.
Thick leather that has been made soft by soaking in warm water and then
shaping it to the part makes a more satisfactory splint. In all cases a
soft bandage should be applied under the splint. The adjustment of the
plaster bandage or splint should be noticed daily, and whenever necessary
it should be removed and readjusted. Injuries to the skin must be carefully
cleaned, disinfected and bandaged before applying the plaster bandage. If
evidence of wound infection occurs later, the bandage must be removed and
the wound treated. Large animals suffering with a fracture of any of the
bones of the limb should be placed in slings. Incomplete fracture should
receive the same treatment as simple fracture. If this is practised, the
danger of its becoming complete is avoided.

[Illustration: FIG. 61.--Shoulder abscess caused by loose-fitting harness.]

HARNESS INJURIES.--This class of injuries is common in horses that are
given steady, hard work, or that are not accustomed to work. Young horses,
when first put to hard work, are especially prone to injuries from the
collar. A large proportion of these injuries are due to an ill-fitting
harness or saddle.

When the harness is not adjusted or fitted properly, there is severe
pressure on certain parts. This is the common cause of shoulder abscesses
(Fig. 61), sore necks and sit-fasts. Rough, uneven surfaces on the faces of
the collar and saddle are the common causes of galling. The character of
the work is an important factor. Work that requires the animal to support
weight on the top surface of the neck is productive of sore neck. Heavy
work over rough, uneven ground frequently causes shoulder abscesses and
strained muscles.

The simplest and most common harness injuries are galling, sore shoulders
and sore neck. Harness galls first appear as flat, painful swellings. On
raising the collar from the skin the inflamed area appears dry and the
surrounding hair is wet with sweat. Later, the skin becomes hard and its
outer layer, and sometimes the deeper layer as well, slough, or is rubbed
off by friction of the harness. The surface then appears red and moist.
Fluctuating swellings due to small collections of blood and lymph sometimes
form. Sometimes, small areas on the face of the shoulder and that portion
of the back pressed on by the saddle become swollen, indurated and hard and
give the shoulder a rough appearance. Continuous irritation from the collar
may cause an inflammatory thickening of the subcutaneous tissue in the
shoulder region, and the skin appears loose and somewhat folded. This
uneven surface is productive of chronic collar galls.

_A sit-fast_ is characterized by a large swelling at the top of the neck,
followed by a deep sloughing of the tissues. A slightly swollen, wrinkled
condition of the skin over the top of the neck is sometimes present in
horses that resist the attendant, when he attempts to handle the part or
harness the animal. This form of sore neck is evidently very painful,
although little evidence of inflammation is present.

Strain of shoulder muscles and shoulder abscesses have been discussed under
their separate heads.

_The treatment is very largely preventive_. Too little attention is given
to the proper fitting of the harness and saddle. A well-fitted collar that
properly distributes the weight on the shoulder, and is neither too small
or too large at the top of the neck, is the best preventive for shoulder
and neck injuries. Old, ill-fitting, lumpy collars should not be used.
Neither should the same collar be used for different horses. Farmers should
avoid using sweat pads that are lumpy or soaked with sweat. If soft and
dry, such pads are useful in preventing galling. The surfaces of the collar
or saddle that come in contact with the skin should be kept smooth and
clean. In the spring of the year, it is advisable to bathe the shoulders of
work horses with cold water twice a day. Bathing the shoulders with the
following preparation is a useful preventive measure: lead acetate four
ounces, zinc sulfate three ounces and water one gallon. Smooth leather pads
for the top of the collar and saddle are useful preventive and curative
agents.

_Galls are lest treated by rest_. Ointments or "gall cures" are usually
applied. The following dry dressing dusted over the red, moist, abraded
surfaces is quite healing: tannic acid one ounce, boric acid four ounces,
and calomel two ounces. This may be dusted over the part two or three times
daily. Dry, abraded surfaces may be treated by applying a mixture of
glycerine four ounces, tannic acid one-half ounce and carbolic acid one
dram. In operating for the removal of fibrous enlargements, thickened skin
and abscesses on the front of the shoulder, it is advisable to make the
incision in the skin well to the side of the face of the shoulder in order
to avoid scarring the surface that comes in contact with the collar.


QUESTIONS

1. Name and describe the different kinds of fractures.

2. What are the symptoms of fracture?

3. Describe the treatment of fractures.

4. What are the causes of harness injuries?

5. Describe the treatment of the different harness injuries.



CHAPTER XXIII

COMMON SURGICAL OPERATIONS


DEHORNING CATTLE.--It is very often necessary to remove the horns of cattle
in order to prevent their injuring or worrying certain individuals in the
herd. This operation is of greatest economic importance in dairy and
feeding cattle. When first practised, the dehorning of mature cattle was
condemned by some persons who deemed it an inhuman and unnecessary
operation. It is surely a humane act to remove the horns of cattle that are
confined in small yards and pastures, and prevent them from painfully, or
seriously, injuring one another.

In most localities there are men who are well equipped to dehorn cattle,
and able to perform this operation for a very moderate fee. It is not
advisable to attempt to dehorn a number of adult cattle if the operator is
not well equipped for the work. Unless a well-constructed dehorning rack is
available for confining the animals, there is danger of injuring them and
it is very difficult to saw off the horn quickly and satisfactorily. This
increases the pain that the animal suffers, and horn stubs soon develop.

Good equipment, such as a chute, saw or clippers, is necessary. A dehorning
chute should be built of plank with a good frame well bolted together, with
stanchion and nose block for confining the head. Most operators prefer a
meat saw for cutting off the horns. It is preferable to dehorning shears,
as there is danger of fracturing the frontal bone when removing the horns
of mature cattle. The best form of dehorning shears have a wide V in the
cutting edge.

_The operation is very simple_. The horn should be cut off at a point from
one-quarter to one-half an inch below the hair line or skin. If this is not
practised, an irregular horn growth or stub of horn develops. It is usually
unnecessary to apply anything to the wound. If the animal does not strike
or rub the part, the clot that forms closes the blood-vessels and the
haemorrhage stops. In case of haemorrhage of a serious nature, a small
piece of absorbent cotton may be spread over the surface of the wound, and
pushed in to the opening in order to keep it in place. Pine tar may be
smeared over this dressing. Some operators prefer cauterizing the wound
with a red-hot iron for the purpose of preventing haemorrhage. During warm
weather, the wound should be washed daily with a two per cent water
solution of a coal tar disinfectant, until healing is well advanced. A very
necessary after-treatment is the washing of the part after two or three
days for the purpose of removing the dried blood.

The opening at the base of the horn communicates directly with the frontal
sinus, a large cavity situated between the two plates of the frontal bone.
Sometimes the bone is slivered, or the wound becomes infected and inflamed.
This may be due to a dirty dehorning saw, or getting dirt into the wound.
The inflammation may extend to the sinus and a heavy discharge from the
cavity occur. This complication may be prevented by placing the saw or
cutters in a disinfectant when not in use, and cleaning and disinfecting
the wound very carefully for a few days after the operation.

_The horn buttons of calves_ from a few days to one week of age can be
destroyed, and the growth of the horn prevented by applying caustic soda or
potash to them. The method of procedure is as follows: Clip away the hair
from around the base of the horn tissue and apply a little vaseline to the
skin near, but not close to, the base of the horn; moisten the horn button
and rub it two or three times with the end of the stick of caustic; do not
allow the calf to go out in the rain for a few days after applying the
caustic. The horns of calves a few weeks of age may be removed with a sharp
knife or calf dehorner.

CHOKING.--This is a common accident in cattle and horses. The object that
causes the choke may be lodged in the pharynx or oesophagus. Certain
individuals are more prone to choke while feeding than others. This is
because of their habit of eating greedily, and swallowing hastily without
properly mixing the bolus with the saliva. For this reason, choking occurs
when the animal is eating dry feed. Cattle frequently become choked on
pieces of such food as roots and apples that are too large to readily pass
down the oesophagus. Sharp objects taken in with the food sometimes become
lodged in the oesophagus or pharynx.

_The symptoms_ differ in complete and partial choke. In the latter, the
symptoms are not very characteristic. The animal may stop feeding, but
shows very little evidence of suffering pain. It may be able to swallow a
little water. On attempting to drink, a part of the water may be returned
through the nose, the same as in complete choke. Ineffectual efforts to
swallow, salivation, coughing, hurried respiration, and an anxious
expression of the face occur in complete choke. Bloating may complicate
this accident in ruminants. After partial choke has persisted for a day or
two, the animal appears dejected or distressed. Pressure on the trachea by
hard objects may cause difficult respiration.

Mechanical pneumonia sometimes occurs. This is due to the food and water
that the animal may attempt to swallow, being returned to the pharynx and
passed into the air passages and lungs.

_The treatment_ is as follows: Animals that have choked should not be given
access to feed of any kind. Any attempt to take food or drink water may
result in pneumonia. It may be necessary to drench the animal with a very
small quantity of water for the purpose of diagnosis. The most common form
of choke in horses is that due to accumulation of dry food in the
oesophagus. The administration of a drug that stimulates the secretion of
saliva is a very successful method of relieving this form of choke.
Pilocarpine is the drug commonly used. Cheap whips should not be introduced
into the oesophagus for the purpose of dislodging the foreign body. There
is always danger of the whip becoming broken off, and the broken part
lodging in the oesophagus. Neither should such rigid objects as a broom or
rake handle be introduced, because of the danger from serious injury to the
walls of the pharynx and oesophagus. The flexible probang, which is usually
made of spiral wire covered with leather, is a very useful instrument to
relieve choke when in the hands of an experienced operator. If the object
causing the choke is situated in the neck portion of the oesophagus, it may
sometimes be moved forward, or toward the stomach by pressure with the
fingers.

CASTRATION.--The castration of the male is a common operation in domestic
animals. The purpose of the operation is to render the animal more useful
for work or meat production.

_The age_ at which the operation is performed varies in the different
species. The colt is usually castrated when he is one year old, and the
calf, pig and lamb when a few weeks or a few months of age. It is not
advisable to castrate the young at weaning time. The operation and the
weaning together may temporarily check the growth of the animal. Colts that
are undeveloped and in poor flesh, or affected with colt distemper, should
be allowed to recover before they are operated on. In all animals, it is
advisable to wait until after they have recovered from disease and become
thrifty and strong.

The spring, early summer and fall are the most suitable seasons for
castrating the young. It may be practised during the hot or cold months of
the year with little danger from wound infection or other complications,
providing the necessary after-attention can be given.

_The preparation of the animal_ for the operation by withholding all feed
for about twelve hours is very advisable. If this is practised, the stomach
and intestines are not distended with feed, and the young are cleaner,
easier to handle and suffer less from castration. Clean quarters and
surroundings are very necessary to the success of the operation.

_The instruments required_ are sharp knives, preferably a heavy scalpel and
a probe-pointed bistoury, an emasculator for large and mature animals, and
surgeon's needles and suture material. Ropes and casting harness are
frequently used for confining and casting the large and mature animals. Two
clean pans or pails filled with a two per cent water solution of liquor
cresolis compositus, or an equally reliable disinfectant, should be
provided for cleaning the scrotum and neighboring parts and the
instruments. Pieces of absorbent cotton or oakum may be used in washing and
cleaning the scrotum. The instruments should be sterilized in boiling water
before using.

_If a number of pigs or lambs_ are to be castrated, it is best to confine
them in a small, clean, well-bedded pen. This enables the attendant to
catch them quickly and without unnecessary excitement or exercise. They
should be taken to an adjoining pen to be castrated. The scrotum should be
washed with the disinfectant, and the testicles pressed tightly against the
scrotal wall. An incision parallel with the middle line or raphe and a
little to one side is made through the skin and the coverings of the
testicle, and the testicle pressed out through the incision. The testicle
and cords are then pulled well out and the cord broken off with a quick
jerk and twist, or scraped off with a knife. The latter method is to be
preferred in large lambs if the operator does not have an emasculator. The
incision in the scrotum should be extended from its base to the lowest
part, in order to secure perfect drainage.

_Young calves_ may be castrated in the standing position or when cast and
held on the side. The method of operating is the same as recommended for
pigs and lambs.

_The castration of the colt_ may be performed in either the standing
position or when cast. The method of operating is the same as practised in
the smaller animals with the exception of cutting off the cord. The
emasculator is used here. This instrument crushes the stump of the cord and
prevents haemorrhage from the cut ends of the blood-vessels. Careful
aseptic precautions must be observed in operating on colts, as they are
very susceptible to wound infection and peritonitis.

The blood-vessels of the testicular cord are larger in the adult animals,
and the danger from haemorrhage is greater than in the young. For this
reason, it is advisable to use an emasculator in castrating all mature
animals.

Complications Following Castration.--The _haemorrhage_ from the wound and
stump of cord is usually unimportant in the young animals. Serious
haemorrhage from the vessels of the cord sometimes occur in the adult, and
a persistent haemorrhage results when a subcutaneous vein is cut in making
the incision in the scrotum. This complication is not usually serious, and
can be prevented and controlled by observing proper precautions in cutting
off the cord, or by picking up the cut ends of the vessel and ligating it.
Packing the scrotal sack with sterile gauze or absorbent cotton, and
closing the incision with sutures may be practised for the purpose of
stopping this form of haemorrhage. The packing should be removed in about
twelve hours.

_The infection of the wound_ always follows castration. If the incision is
small and the operation is followed by swelling of the neighboring tissues,
the clotted blood, wound secretions and pus become penned up in the scrotal
sack. Local blood poisoning or peritonitis follows. This is not an uncommon
complication. It can be prevented by aseptic precautions in operating, and
insuring good drainage by extending the incision to the lowest part of the
scrotal sac. The scrotal sac always contracts down and becomes more or less
swollen within a day or two following castration. We must keep this in mind
when enlarging the opening, and be sure and make it plenty large to permit
the escape of the infectious matter. In castrating sheep, all wool in the
region of the scrotal sac should be clipped off, as this interferes with
drainage from the wound.

_Exercise following castration_ is almost as essential as clean quarters.
Lack of exercise leads to _oedematous swelling_ in the region of the
scrotum, and the lips of the incision may become adhered if the animal is
at rest. Colts and all mature animals that are confined in close quarters
should be examined within forty-eight hours following the operation, and
the condition of the wound noted. If closed, the hands should be cleaned
and disinfected, and the adhesion broken down with the fingers. It is best
to exercise horses daily.

It is unsafe to expose castrated animals to cold, damp, chilly weather. The
shock and soreness resulting from the operation render the animal highly
susceptible to pleurisy and pneumonia. This is especially true of young
colts.

_Inguinal hernia_ or "_rupture_" may complicate the operation. This form of
hernia is quite frequently met with in pigs, and only occasionally in the
other animals. This complication is usually overcome by practising what is
commonly termed the covered operation. The pig is usually held or hung up
by the hind legs. A larger animal is placed on its back. The hernia is
reduced by manipulating the mass of intestines with the fingers, so that
they drop back into the abdominal cavity. The part is carefully cleaned and
disinfected and an incision made through the scrotal wall, and the thin
covering or serous sac in which the testicle is lodged is exposed. The
testicle with the cord and covering is drawn well out of the scrotum and
held by an attendant. The operator then passes a needle carrying a strong
silk thread through the cord and covering, below the point where he intends
severing it. The needle is removed and the cord and covering ligated at
this point. The cord is then cut off about one-half an inch from the
ligature, and the incision in the scrotum made plenty large in order to
insure drainage.

It is very essential to the success of this operation that the animal be
dieted for twelve or eighteen hours before attempting to operate. The
after-treatment consists in giving the animal separate quarters and feeding
a light diet.

_Enlarged or scirrhous cords_ follow infection of the wound, usually with
spores of a certain fungus (_Botryomyces_). This complication more often
follows castration of cattle and pigs than of colts. Wrong methods of
operating, such as leaving the stump of the cord too long and insufficient
drainage for the pus and wound secretions, are the factors that favor this
complication. Scirrhous cords or fibrous tumors should be dissected out and
removed before they have become large and begun breaking down.

CASTRATION OF RIDGELING OR CRYPTORCHID ANIMALS.--In the ridgeling animal
one or both of the testicles have not descended into the scrotal sac, and
are usually lodged in the inguinal canal or abdominal cavity. If the
testicle is lodged in the inguinal canal the animal is termed a "flanker."
In yearling colts the testicular cord is sometimes short, and the testicle
is situated high up in the scrotum and inguinal canal. In examining a
supposed cryptorchid colt, he should be twitched. This may cause the
testicle to descend into the scrotum.

The castration of a true cryptorchid requires a special operation. When
properly performed and the animal given special after-care, the operation
is not followed by any serious complications. An abnormally large, diseased
testicle is sometimes met with that cannot be removed in the usual way, and
which complicates and increases the difficulty of operating.

CAPONIZING.--The castration or caponizing of the male chicken is commonly
practised in certain localities. This operation changes the disposition of
the cockerel. He becomes more quiet and sluggish, never crows, the head is
small, the comb and wattles cease growing and the hackle and saddle
feathers become well developed. A capon always develops more uniformly and
is larger than the cockerel.

_The best time to caponize the cockerel_ is when he weighs between two or
three pounds. If older and heavier, the testicle becomes so large that it
is very difficult to remove, and the danger from tearing the spermatic
artery and a fatal haemorrhage resulting is greater.

There are several kinds of _caponizing instruments_. They may be purchased
in sets. Each set should contain an instrument for removing the testicle; a
knife for making the incision through the abdominal wall; a sharp hook for
tearing through the thin membrane; spring spreader for holding the lips of
the incision apart; a blunt probe for keeping the intestines out of the way
of the operator; and a pair of tweezers for removing clots of blood. The
different instruments for removing the testicles are a spoon-like scoop,
spoon forceps and cannula. The spoon-like scoop is preferred by most
operators.

_The cockerel_ is confined for the operation by passing a strong noose of
cord around both legs, and a second noose around the wings close to the
body, that have weights fastened to them. The cords pass through holes or
loops in a barrel or board that is used for an operating table. This holds
the cockerel firmly and prevents his struggling.

_The bird should be prepared_ for the operation by withholding all feed and
water for a period of twenty-four hours or longer, for the purpose of
emptying out the intestine. The operator must have a strong light, in order
to work quickly and safely. Direct sunlight or electric light should be
used.

The instruments should be placed in a two per cent water solution of
carbolic acid. A second vessel containing a two per cent water solution of
liquor cresolis compound for cleaning the skin is necessary. Absorbent
cotton should be used for washing the wound.

_The general method of operating_ is as follows: The incision is made
between the last two ribs and in front of the thigh. The feathers over this
region should be removed, and the skin pulled to one side before making the
incision. An incision about one and one-half inches in length is made
through the skin and muscles, and the spreader inserted. The sharp hook is
then inserted and the thin serous membrane over the intestine is torn
through. The testicles are situated in the superior portion of the
abdominal cavity or under the back. On pushing the intestines to one side,
both testicles, which are about the size of a bean and yellowish in color,
can be seen. The lower one should be removed first. After removing both
testicles, blood clots, feathers, or any foreign body that may have gotten
into the wound should be picked up with the tweezers before removing the
spreaders and allowing the wound to close. No special after-treatment is
required.

_The most common complication_ is rupture of the spermatic artery. This
occurs at the time the testicle is torn loose and may be due to careless
methods, or operating on cockerels that are too large. If all of the
testicle is not removed from the abdominal cavity, the bird is termed a
"slip." Sometimes air puffs form after the operation. These should be
punctured with a sharp knife.

OVARIOTOMY, "SPAYING."--The removal of the ovaries, or ovariotomy, is
practised for the purpose of rendering the female more useful for meat
production, prolonging the period of lactation, overcoming vicious habits
and preventing oestrum or heat. The operation is commonly performed in the
heifer and bitch, occasionally in the mare, and at present rarely in the
sow.

_Heifers_ are usually spayed between the ages of eight and twelve months;
the _bitch_ and _sow_ when a few months old, or before the periods of heat
have begun. The _mare_ is spayed when mature. It is possible to spay the
female at any age, but the ages mentioned are the most convenient. Pregnant
animals should not be operated on. The season of the year makes little
difference in the results, providing the animal can be kept under close
observation and given the necessary care and treatment. The spring of the
year, just before turning the herd on pasture, is the best season to spay
heifers.

_All animals should be prepared_ for the operation by withholding all feed
for at least twenty-four hours before they are operated on, and it may be
advisable to give them a physic. It is easier to operate when the
intestinal tract is comparatively empty, and the death rate is lower than
when the animal is not properly prepared for the operation.

_The method of operating_ is not the same in the different species. In
young heifers and sows, the flank operation is preferred, and in mares and
cows, the vaginal operation. The median line operation is practised in
bitches. A spaying emasculator, or ecraseur, are the special instruments
need for removing the ovaries.

The animal must be properly confined for the operation. Heifers are usually
held in the standing position by fastening the head securely, and crowding
the left side of the animal against a solid board partition, or side of a
chute. If the vaginal operation is performed, the mare or cow may be
confined in stocks. The bitch is usually anesthetized and placed on her
back on a table that is inclined, so that the hind parts are elevated.

Ovariotomy cannot be successfully performed by an untrained and
inexperienced operator. The necessary precautions against the infection of
the part must be observed, in order to promote the healing of the wound and
prevent peritonitis. The seat of the operation should be carefully cleaned
and disinfected.

_Following the operation_ the animal should be fed a spare diet for a few
days. This is a very necessary part of the care of the bitch. The general
condition of the animal should be noted daily until there is no further
danger from wound infection. Healing is usually completed in from seven to
twelve days. The sutures should then be removed, and if stitch abscesses
occur, the part should be washed with a disinfectant.


QUESTIONS

1. What is the purpose of dehorning cattle? Give different methods of
   removing the horns.

2. Give the causes and treatment of choking.

3. What is the purpose of castration and ovariotomy?

4. At what age is it best to practise castration and ovariotomy?

5. In what way should an animal be prepared for castration? Give a
   description of the method of castration in the different animals.

6. What special care should be given following castration?

7. What are some of the complications that may follow castration?



PART V.--PARASITIC DISEASES



CHAPTER XXIV

PARASITIC INSECTS AND MITES


Parasitic insects are common causes of skin diseases in domestic animals.
The diseased conditions of the skin, and the irritation that they may cause
the animal, depend on the life history and habits of the parasite. Species
that are unable to live independently of a host and are permanent parasites
are usually the most injurious to the animal. This is especially true of
parasites that are capable of puncturing the skin or burrowing into it.
Temporary parasites may cause fatal forms of disease. This is true of the
larva? of the sheep bot-fly, which develop in the sinuses of the head,
causing severe inflammation of these parts, nervous symptoms and death. The
character of the symptoms of a parasitic disease depends on the habits of
the parasite, and the tissue or organ, that it may attack.

The parasitic flies belong to the order _Diptera_, and the families
_Muscidae_ and _OEstridae_. Fleas belong to the sub-order _Pulicidae_. The
order _Hemiptera_ includes the lice, and the most important families are
_Pediculidae_ and _Ricinidae_. Mites and ticks belong to the order
_Acarina_. The most important parasites belonging to this order are the
_Sarcoptidae_ and _Ixodidae_.

OESTRIDAE.--The three common bot-flies are the _Gastrophilus equi_,
_Hypoderma lineata_ and _OEstrus ovis_. These flies are important because
of the parasitic habits of their larva. They inhabit the stomach and
intestines of horses (Fig. 62); the subcutaneous tissue and skin of cattle;
and the sinuses of the head and nasal cavities of sheep.

_The common bot-fly of the horse_ (_G. equi_) has a heavy, hairy body. Its
color is brown, with dark and yellowish spots. The female fly can be seen
during the warm weather, hovering around the horse, and darting toward the
animal for the purpose of depositing the egg. The color of the egg is
yellow, and it adheres firmly to the hair. It hatches in from two to four
weeks, and the larva reaches the mouth through the animal licking the part.
From the mouth, it passes to the stomach, where it attaches itself to the
gastric mucous membrane (Fig. 62). Here it remains until fully developed,
when it becomes detached and is passed out with the fasces. The third stage
is passed in the ground. This takes place in the spring and early summer
and lasts for several weeks, when it finally emerges a mature fly.

[Illustration: FIG. 62.--A piece of the wall of the horse's stomach showing
the bot-fly larvae attached.]

_The bot-fly of the ox_ (_H. lineata_) is dark in color and about the size
of a honey-bee. On warm days, the female may be seen depositing eggs on the
body of the animal, especially in the region of the heels. This seems to
greatly annoy the animal, and it is not uncommon for cattle to become
stampeded. The egg reaches the mouth through the animal licking the part.
The saliva dissolves the shell of the egg and the larva is freed. It then
migrates from the gullet, wanders about in the tissue until finally it may
reach a point beneath the skin of the back. Here the larva matures and
forms the well-known swelling or warble. In the spring of the year it works
out through the skin. The next stage is spent in the ground. The pupa state
lasts several weeks, when the mature fly issues forth.

_The bot-fly of sheep_ (_O. ovis_) resembles an overgrown house-fly. Its
general color is brown, and it is apparently lazy, flying about very
little. This bot-fly makes its appearance when the warm weather begins, and
deposits live larvae in the nostrils of sheep. This act is greatly feared
by the animals, as shown by their crowding together and holding the head
down. The larva works up the nasal cavities and reaches the sinuses of the
head, where it becomes attached to the lining mucous membrane. In the
spring, when fully developed, it passes out through the nasal cavities and
nostrils, drops to the ground, buries itself, and in from four to six weeks
develops into the mature fly.

SYMPTOMS OF BOT-FLY DISEASES.--The larvae of the bot-fly of the horse do
not cause characteristic symptoms of disease. Work horses that are groomed
daily are not hosts for a large number of "bots," but young and old horses
that are kept in a pasture or lot and seldom groomed may become unthrifty
and "pot bellied," or show symptoms of indigestion.

Cattle suffer much pain from the development of the larva of the _H.
lineata_. During the spring of the year, the pain resulting from the
presence of the larvae beneath the skin and the penetration of the skin is
manifested by excitement and running about. Besides the loss in milk and
beef production, there is a heavy yearly loss from the damage to hides.

The parasitic life of the bot-fly of sheep results in a severe catarrhal
inflammation of the mucous membrane lining the sinuses of the head, and a
discharge of a heavy, pus-like material from the nostrils. The irritation
produced by the larvae may be so serious at times as to result in nervous
symptoms and death.

TREATMENT OF BOT-FLY DISEASES.--The treatment of the different bot-fly
diseases is largely preventive. This consists in either the destruction of
the eggs or the larvae.

The different methods of destroying the eggs of the bot-fly of the horse
are clipping the hair from the part, scraping off the eggs with a sharp
knife, or destroying them by washing the part infested with eggs with a two
or three per cent water solution of carbolic acid. This should be practised
every two weeks during the period when the female deposits the eggs.

Housing the cattle, or applying water solutions of certain preparations to
the skin that may keep the female from depositing eggs, may be practised
for the prevention of the ox-warble. The most practical method of ridding
cattle of this pest is to destroy the larvae. This can be done by examining
each animal and locating the swelling or warble and injecting a few drops
of kerosene into the opening in the skin. A better method is to enlarge the
opening in the skin with a sharp knife, squeeze out the grub and destroy
it. This should be practised in late winter and early spring.

The application of pine tar to the nostrils of sheep is the most practical
method of preventing "grub in the head." This should be practised every few
days during the summer months. A very good preventive measure is plenty of
shade for the flock. Valuable animals may be treated by trephining into the
head sinus and removing the "grub."

LICE.--The sucking lice belong to the genus _Hoematopinus_, and the biting
lice of mammals belong to the genus _Trichodectes_. Different species of
sucking and biting lice occur on the different species of farm animals.
Poultry act as hosts for many different species of biting lice belonging to
the following genuses: _Lipiurus, Goniodes, Goniocotes_ and _Menopon_.

_The common sucking lice_ occurring on animals are the large-headed horse
louse, _H. macrocephalus_; the long-nosed ox louse, _H. tenuirostris_; the
large-bellied ox louse, _H. curysternus_; the _H. stenopses_ of sheep; _H.
suis_ of swine; and the _H. piliferus_ of the dog.

The _common biting lice_ (Fig. 63) that are found on domestic animals are
the _T. pilosus_ and _T. pubescens_ of solipeds, _T. scalaris_ of the ox,
_T. spoerocephalus_ of sheep and goats, _T. latus_ and _T. subrostratus_ of
the dog and cat. _Menopon palidum, Lipiurus variabilis_ and _Gonoides
dissimilis_ are the common lice found on poultry.

[Illustration: FIG. 63.--Biting louse.]

SYMPTOMS OF LICE.--The symptoms of lousiness depend on the variety of lice
present, the degree to which the animal is infested with them, its physical
condition and the care that it receives. Lice multiply more rapidly and
cause greater loss during the winter months than they do in the summer,
when the animals are not housed and the opportunity for infection from the
surroundings is not so great. The sucking louse (Fig. 64) is the most
injurious and irritating. The irritation and loss of blood that the animal
may suffer when badly infested by this parasite may result in marked
unthriftiness. Young and old animals that are not well cared for suffer
most. The biting louse may bite through the superficial layer of the skin,
and cause the animal to bite and rub the part. This irritation to the skin
prevents the animal from becoming rested, and after a time seriously
interferes with its thriftiness.

_Horses and mules_ show a staring, dirty, rough coat. The mane and tail may
become broken and matted. The animal rubs against the stall, fences and
trees, and bites the skin in its efforts to relieve the irritation. On
examining the coat, nits are found adhering to the hair (Fig. 65). We
should examine the parts of the skin covered by the long hair for the
sucking lice; and the withers, abdomen and limbs for the biting lice.

[Illustration: FIG. 64.--Sucking louse (much enlarged).]

[Illustration: FIG. 65.--Nits attached to hair (much enlarged).]

_The symptoms of lousiness in cattle_ are about the same as occur in
horses. Licking and rubbing the skin are prominent symptoms in cattle, and
the coat becomes dirty and rough. The licked part is matted and curled. The
lice may be discovered by parting the hair along the back and rump.

_The biting louse of sheep_ causes the fleece to become matted and tufts of
wool are pulled out. This is brought about by the sheep rubbing and
nibbling the fleece, and the lice cutting through the wool. The loss due to
the damage to the fleece is usually greater than that resulting from
unthriftiness.

_The hog-louse_ is the largest specie known. As well as the largest, it is
the most common of all lice found on domestic animals. The favorite points
of attack are the under surface of the body, the neck and the inside of the
thighs. The irritation and itching are severe, and the hog rubs and
scratches the skin. Young hogs suffer most from this parasite, and their
thriftiness is greatly interfered with.

The long-haired breeds of _dogs_ suffer more from lice than the
short-haired breeds. The almost constant scratching and biting of the skin
result in its becoming badly irritated and scabby. The symptoms differ
little from irritation to the skin caused by fleas, but the presence of
biting or sucking lice enables the person making the examination to
determine the cause of the irritation.

Lice are the most common parasites of _poultry_. It is uncommon to meet
with a flock of fowls that are not hosts for one or more of the many
different varieties of bird lice. Restlessness, picking, scratching,
flapping the wings, abandoning the nest and loss of condition are common
symptoms. Young birds suffer most from lice. This is especially true of
young chickens, death frequently resulting. Old fowls may show little
inconvenience unless badly infested. The finding of the lice with the head
imbedded in the skin or on the feathers enables the person making the
examination to positively diagnose the case. The head, back, region of the
vent and beneath the wings are the parts that should be carefully examined
for lice.

TREATMENT OF LOUSINESS.--The preventive treatment is very important. This
consists in carefully examining all animals or birds that have been
purchased recently, and if found to harbor lice, excluding them from the
herd or flock until after they have been properly treated.

It is impossible to rid animals of lice if the quarters are thoroughly
cleaned and disinfected. This is necessary in order to destroy lice that
have become scattered about by the lousy animals, and prevent the
reinfection of the treated animals. The best method to use in cleaning the
quarters is to remove all litter and manure from the stable or houses and
their immediate surroundings. It should be burned, or hauled to a field or
lot where other animals cannot come in contact with it for a few months.
The walls, floors and partitions should be sprayed with a three per cent
water solution of liquor cresolis compositus. Lime may be scattered about
the buildings, yards and runs. The most satisfactory method of destroying
lice on the bodies of animals is by washing or dipping in a water solution
or mixture of some reliable disinfectant or oil.

_Running hogs through a dipping tank_ that contains a one or two per cent
water solution of liquor cresolis compositus, or a coal tar disinfectant,
or that has from three-fourths to one and one-half inches of oil on top of
the water, is the most satisfactory method of destroying the hog louse.
Because of the thinness of the hog's coat and the danger from irritating
the skin when strong solutions of a disinfectant are used, most swine
breeders prefer crude oil as a remedy for lousiness in hogs. Crude oil may
be applied to the bodies of hogs with a swab. If this method is practised
instead of dipping, it is advisable to crowd the hogs into a small pen, and
apply the oil in front and between the thighs and back of the arms. This
may be practised during the cold weather when it is impossible to dip the
animals.

_Horses_ may be washed with a one or two per cent water solution of liquor
cresolis compositus, or a coal tar disinfectant. If the weather is cold, it
is advisable to pick a sunny day, and blanket the animal after rubbing it
as dry as possible in order to prevent chilling and catching cold.

_Cattle_ may be treated in the same manner as horses. Mercurial ointment
rubbed in small amounts on the skin back of the horns and ears, where the
animal cannot lick it, is a common remedy. The absorption of a small amount
of this drug does the animal no harm, but a larger quantity may salivate
it.

_Sheep_ are treated by dipping in a water solution of a reliable coal tar
disinfectant. This should not be practised during cold weather, as the
fleece does not dry out. Insect powder may be dusted into the fleece when
it is impossible to dip the animal.

A very satisfactory treatment for lousiness in _dogs_ and _cats_ is to wash
them with carbolized soap. We should wait a few minutes before rinsing off
the soapy lather and drying the coat.

A number of different remedies are used for the treatment of lousiness in
_poultry_. Dust baths and insect powder are recommended. Ointments are
commonly used. One part sulfur and four parts vaseline, or lard, may be
made into an ointment and applied to the head, neck, under the wings and
around the vent. Mercurial ointment may be applied to the margin of the
vent. Neither of them should be used for destroying lice on young chicks.
Mercurial ointment should be used very carefully because of its poisonous
effect. Lard may be used for destroying lice on young chicks. Crude
petroleum may be sprayed among the feathers by a hand-sprayer, while the
fowls are suspended by the feet.

[Illustration: FIG. 66--Sheep-tick.]

None of the disinfectants and oils recommended for dipping and washing
lousy animals destroy the nits. This makes it necessary to re-treat the
animal in from eight to ten days after the first treatment.

THE SHEEP-TICK.--This is not a true tick. It resembles a fly more than it
does a tick, and its right name is _Melophagus ovinus_ (Fig. 66). Louse-fly
is a better name for this parasite than tick, as its entire life is spent
on the body of a sheep. The general color of the body is brown. The legs
are stout, covered with hair and armed with hooks at their extremities. The
mouth parts consist of a tubular, toothed proboscis with which the parasite
punctures the skin and sucks the blood. Within a few hours after birth, the
larvae develop into pupae, which are hard, dark brown in color and firmly
glued to the wool. The young louse-fly emerges from the pupa in from three
to four weeks.

The sheep-tick is a very common external parasite. The adult parasites and
the pupae are large and easily found. When badly infested with ticks, a
sheep will rub, dig and scratch the skin and fleece. This results in pieces
of wool becoming pulled out and the fleece appears ragged. After clipping
the ticks migrate from the ewes to the lambs, which may become unthrifty
and weak.

_The treatment_ consists in dipping the flock in a one or two per cent
water solution of a coal-tar dip. Dips containing arsenic are most
effective in ridding sheep of ticks.

[Illustration: FIG. 67.--Sheep scab mite, ventral view. (From Farmers'
Bulletin No. 159, United States Department of Agriculture.)]

SCABIES.--This parasitic disease is one of the oldest and most prevalent
diseases of the skin. It is commonly known as scab or mange. The animals
most commonly affected are sheep, horses and cattle.

_The disease is caused_ by _small mites_ or _acari_ that are naturally
divided into the _Sarcoptes_, which burrow under the epidermis, forming
galleries; the _Psoroptes_, which live on the surface of the skin where
they are sheltered by scabs and scurf; and the _Symbiotes_, which also live
on the surface of the skin, but prefer the regions of the hind feet and
legs.

Acari multiply rapidly and live their entire life on the body of the host.
A new generation is produced in about fifteen days. Gerlach has estimated
the natural increase in three months at 1,000,000 females and 500,000
males. Scab and mange are exceedingly contagious diseases.

[Illustration: FIG. 68.--Sheep scab.]

_Common sheep scab_ is caused by that specie of mites known as the
_Psoroptes communis var. ovis_ (Fig. 67). Any part of the body may become
affected. The bites of the mites greatly irritate the skin, and the animal
scratches, bites and rubs the part in its effort to relieve the intense
itching. The skin becomes inflamed and scabby, the wool is pulled and
rubbed out, and the fleece becomes ragged (Fig. 68). By pulling wool out of
the newly infested area, or collecting skin scrapings and placing this
material on black paper in a sunny, warm place, the mites may be seen
crawling over the paper. This method of diagnosis should be resorted to in
all suspicious cases of skin disease, and before the disease has developed
to any great extent.

The mite that most commonly causes _mange in cattle_ is the _Psoroptes
communis var. bovis_. It may invade the skin in the different regions of
the body, but it is in the regions of the tail and thighs that the first
evidence of the mange is noticed. The animal rubs, scratches, and licks the
part. The itching is intense. The hair over the part is lost and the skin
appears inflamed, thickened, moist, or covered with white crusts. Cracks
and sores may form in the skin. The examination of scrapings from the
inflamed skin should be practised in order to confirm the diagnosis.

_Mange in horses_ may be caused by either psoroptic or sarcoptic mites.
_Psoroptes communis var. equi_ seems to be the more common parasite. The
itching is intense. The inflamed areas are small at first and scattered
over the regions of the rump, back and neck (Fig. 69). After a time the
small areas come together and form large patches, and further spreading of
the inflammation results from grooming, scratching and biting the skin.
Scattered, elevated eruptions on the skin from which the hair has dropped
out are first noticed. These parts may show yellowish scabs. Later the skin
is thickened, smooth, wrinkled, cracked, or covered with sores. Scrapings
made from the inflamed areas of the skin may show the psoroptic mites.

_Mange in hogs_ is comparatively rare. It is caused by one of the sarcoptic
mites. The thin portions of the skin are usually first invaded. There are
violent itching and rubbing, and small, red elevations occur on the skin in
the region of the ears, eyelids or inner surface of the thighs, depending
on the part first invaded. The skin becomes greatly thickened and covered
with crusts and scabs. Pus formation and ulceration may occur.

TREATMENT OF SCAB AND MANGE.--A careful inspection of recently purchased
animals that pass through stockyards, or are shipped from sections where
scab and mange are common skin diseases, is an important preventive
measure. Infected animals should be completely isolated from the herd, and
kept apart from other animals until after they have been treated. Hogs that
are slightly infected should be quarantined and treated. If badly affected,
they should be killed, and the carcass disposed of by burning or burying.

[Illustration: FIG. 69.--A severe case of mange.]

_The different remedies used_ in the treatment of the disease may be
applied by dipping, hand dressing or washing, pouring, smearing and
spotting. The first method is the most satisfactory. The last method may be
used when a small area of the skin is involved, and during the cold
weather. Washing or dipping the animal with a two per cent water solution
of liquor cresolis compositus is an effective remedy for the psoroptic
forms of scab and mange. Tobacco, lime and sulfur, and arsenical dips are
recommended in the treatment of sheep and cattle. Ointments are recommended
for animals that are slightly affected with mange. Lime and sulfur dips are
recommended by the Bureau of Animal Industry. Small infected areas of the
skin may be treated by applying sulfur-iodide ointment. The following
ointment is commonly recommended: potassium sulfide ten parts, potassium
carbonate two parts, and lard three hundred parts.

Sheep cannot be safely dipped for scab during the cold weather. If
thickened and scabby, the skin should be scrubbed with the dip, or the
animal prepared for dipping or washing by first clipping the hair or wool
and scrubbing the skin with water and a good soap. In order to prevent
reinfection, it is necessary to remove the animal to new quarters, or
thoroughly clean and disinfect the old. It is necessary to wash or spray
the fences, floors, walls, brushes and curry-combs with a disinfecting
solution. Manure and other litter should be removed to a place where there
is no danger from its distributing the infection.

DISEASES OF POULTRY CAUSED BY MITES.--Mites or acarina that cause diseases
of poultry may live on the feathers, beneath the skin, and within the body
of the fowl.

_The small, red mite (Dermanyssus gallinae)_ remains on the surface of the
body only when feeding, and spends the rest of the time under collections
of filth and in cracks in the roosts and walls of the house. This parasite
causes the birds to become restless, emaciated and droopy.

_A very small mite (Sarcoptes mutans)_ is the cause of scaly leg. It lives
under the skin. The joints of the feet appear affected, and the foot and
leg become enlarged, roughened and scaly.

_Depluming scabies_ is caused by _Sarcoptes laevis var. gallinae_. This
mite causes the feathers to break off at the surface of the skin. Masses of
epidermic scales may form around the broken ends of the feathers. The
diagnosis can be confirmed by examining the skin lesions and finding the
mite.

_The air sac mite_ (_Cytodites nudus_) may cause sufficient irritation to
the mucous membrane lining the air sacs to seriously obstruct the air
passages with mucus, or produce death from exhaustion. A post-mortem
examination of a fowl that has died of this disease shows the mites on the
surface of the lining membrane of the air-sacs. They appear as a white or
yellow dust.

TREATMENT OF POULTRY DISEASES CAUSED BY MITES.--Diseases of poultry caused
by mites may be prevented by quarantining all recently purchased birds for
a period of from two to four weeks, and by keeping the poultry houses
clean. Birds that are found infested with parasites should be destroyed or
returned. In case the bird is valuable and suffering from external
parasites only, it should be given the necessary treatment.

_Red mites may be destroyed_ by thoroughly cleaning the poultry house, and
spraying the roosts, nests, walls and floor with a three per cent water
solution of liquor cresolis compositus. This should be repeated twice a
week for two weeks.

_Scaly-leg may be treated_ by applying a penetrating oil to the feet and
lower part of the leg. It is advisable to first remove the scales by
scrubbing the part with soap and warm water. Dipping the feet in a mixture
of kerosene one part and linseed oil two parts is recommended. This should
be repeated as often as necessary.


QUESTIONS

1. Describe the different bot-flies.

2. Give the life history of the bot-fly of the horse; of the ox; of sheep.

3. Give the symptoms of bot-fly diseases.

4. Give the symptoms of lousiness.

5. Give treatment for lousiness of different farm animals.

6. What is the damage from the sheep-tick? Give treatment.

7. Describe the injury from scabies and mange.

8. Give treatments for these diseases.

9. Mention the several poultry mites and tell how to treat them.



CHAPTER XXV

ANIMAL PARASITES


The common parasitic diseases of domestic animals are caused by the
following groups of worms: _Flukes_ or _trematoides_; _tapeworms_ or
_Cestoides_; _thorn-headed worms_ or _Acanthocephales_; and _round-worms_
or _Nematoids_. Flat worms, such as tapeworms and flukes, require secondary
hosts. The immature and mature forms of tapeworms are parasites of
vertebrate animals, but an invertebrate host is necessary for the
completion of the life cycle of the fluke. The hog is the only specie of
domestic animals that becomes a host for the thorn-headed worm. The
round-worm is a very common parasite. There are many species belonging to
this class.

[Illustration: FIG. 70.--Liver flukes.]

DISTOMA HEPATICUM (COMMON LIVER FLUKE).--Sheep are the most common hosts
for this parasite. It is present in the gall ducts and livers, and causes a
disease of the liver known as liver rot. The liver fluke is flat or
leaf-like and from thirteen to fifteen mm. long (Fig. 70). The head portion
is conical. It has an oval and ventral sucker, and the body is covered with
scaly spines. The eggs are oval and brownish in color.

_The life history_, in brief, is as follows: Each adult is capable of
producing an immense number of eggs which are carried down the bile ducts
with the bile to the intestine, and are passed off with the faeces. Under
favorable conditions for incubation, such as warm, moist surroundings, the
ova or eggs hatch and the _ciliated embryos_ become freed. The embryo next
penetrates into the body of certain snails and encysts. The _sporocyst_, as
it is now called, develops into a third generation known as _redia_ which
escape from the cyst. The _daughter redia_ or _cercaria_, as they are now
termed, leave the body of the snail and finally become encysted on the
stems of grass, cresses and weeds. When taken into the digestive tract of
the animal grazing over infested ground, the immature flukes are freed by
the digestive juices. They then pass from the intestine into the bile
ducts. The period of development varies from ten to twenty weeks; each
sporocyst may give rise to from five to eight _redia_ and each redia to
from twelve to twenty _cercaria_.

Fluke diseases occur among animals pastured on low, wet, undrained land.
Drying ponds and lakes are the homes of the fresh water snails, and in such
places there are plenty of hosts for the immature flukes. Wet seasons favor
the development of this parasite. Cattle and sheep that pasture on river
bottom land in certain sections of the southern portion of the United
States are frequently affected with fluke diseases.

_The symptoms of liver rot of sheep_ may be divided into two stages. The
first stage is marked by increase in weight and improved condition. In the
second stage of the disease, the animal shows a pale skin and mucous
membrane, dropsical swellings, loss of flesh and weakness. The character of
the symptoms of the disease depends on the age of the animals and the care
that they receive. Young, poorly cared for animals suffer severely from the
disease, and the death rate is usually heavy. The finding of fluke ova in
the faeces is conclusive evidence of the nature of the disease. It may be
advisable to kill one of the sick animals, and determine the nature of the
disease by a post-mortem examination.

[Illustration: FIG. 71.--Tapeworm larvae in liver (_Echinococcus
polymorphus_).]

[Illustration: FIG. 72.--Tapeworms.]

_The treatment is preventive_. Drainage water from a pasture infested with
snails harboring immature flukes is a source of infection, and should not
be used as a water supply for cattle and sheep. In sections where the
disease is prevalent, sheep should not be pastured on low, poorly-drained
land. Such land should be used for pasturing horses and cattle, but if
possible, it should be first drained and cultivated. Careful feeding and
good care may help the affected animals to recover.

[Illustration: FIG. 73.--Tapeworm larvae in the peritoneum (_Cysticercus
cellulosa_).]

TAPEWORMS OR CESTOIDES.--Tapeworms are formed by a chain of segments,
joined together at their ends, and are flat or ribbon-shaped (Fig. 71). The
head segment is small, and possesses either hooks or suckers. It is by
these that the worm attaches itself to the lining membrane of the
intestine. The anterior segments are smaller and less mature than the
posterior segments. Each segment is sexually complete, possessing both the
male and female organs, and when mature, one or more of them break off and
are passed out with the faeces. The mature or ripe segments are filled with
ova. On reaching the digestive tract of a proper host, usually with the
drinking water or fodder, the embryo is freed from the egg. The _armed
embryo_ uses its hooklets in boring its way through the wall of the
intestine. It then wanders through the tissues of its host until it finally
reaches a suitable place for development (Figs. 71 and 73). On coming to
rest, it develops into the larva or bladder-worm, which when eaten by a
proper host gives rise to the mature tapeworm.

The following tables give the most important tapeworms:

ADULT FORMS

Name                   Host            Organ

Taenia expansa         Sheep and ox    Intestine
Taenia fimbriata       Sheep           Liver
Taenia denticulata     Cattle          Intestine
Taenia alba            Cattle          Intestine
Taenia perfoliata      Solipeds        Intestine
Taenia mamillana       Solipeds        Intestine
Taenia echinococcus    Dog             Intestine

LARVAL FORMS

Name                        Host

Cysticercus bovis           Cattle
Cysticercus cellulosa       Swine and man
Cysticercus tennicollis     Cattle, sheep and swine
Coenurus cerebralis         Cattle and sheep
Echinococcus polymorphus    Cattle, sheep, swine and man

The adult tapeworms _Taeniae saginata_ and _soleum_, of which the
_Cysticerci bovis_ and _cellulosa_ are the larvae forms, occur in man. The
larvae are present in meat and pork, and this form of parasitism is termed
beef measles in cattle and pork measles in hogs. Man becomes host for these
two forms of tapeworms through eating measly pork or beef that is not
properly cooked.

The dog is the host for _Taeniae marginala_, _coenurus_ and _echinococcus_.
The larvae forms of these _taeniae_ are the _Cysticercus tennicollis_,
_Coenurus cerebralis_ and _Echinococcus polymorphus_. _C. tennicollis_ is a
parasite of the serous or lining membranes of the body cavities. It is not
of great economic importance. _C. cerebralis_ is a parasite of the brain of
sheep, and may cause a heavy death rate in flocks that are infested with
it. _E. polymorphus_ is a parasite of the liver, but it may occur in other
organs.

THE THORN-HEADED WORM OR ACANTHOCEPHALE.--This parasite requires a
secondary host. In this case a particular species of the May-beetle larva
or white grub that is commonly found about manure piles and in clover
pastures is the host. The hog eats a white grub that is host for the larval
form. The digestive juices free the larva, it then becomes attached to the
intestinal mucous membrane and develops into the adult thorn-headed worm
(Fig. 74). This parasite is characterized by a hooked proboscis or thorn at
its anterior extremity, and the absence of a distinct digestive tract. The
male is much smaller than the female. The eggs are passed out of the
intestine with the faeces.

[Illustration: FIG. 74.--Thorn-headed worms.]

THE ROUND-WORMS OR NEMATOIDS.--Round-worms are very common parasites of
domestic animals (Fig. 75). This group of worms is characterized by their
cylindrical form, the presence of a true digestive canal and the separation
into two sexes, male and female. The life history is more simple than in
the flat worms. Intermediate hosts are not required for the development of
the common forms. The eggs and embryos are deposited by the female in the
intestinal tract, air passages, or excretory ducts of the kidneys of the
host. Development may be completed here, or the eggs and embryos are passed
off with the body excretions. They may live for a short time outside the
animal body, or undergo certain development and again infest a host of the
same species from which they came, through the water, grass and fodder that
the animal may take into its digestive tract.

[Illustration: FIG. 75.--Large round-worm in intestine of hog.]

The following species of nematoids are common parasites of domestic
animals:

SOLIPEDS

  Species                      Organ
Ascaris megalocephala        Intestines
Sclerostoma equinum          Large intestine and blood-vessels
Sclerostoma tetracanthum     Large intestine
Oxyrus curvula               Large intestine
Oxyrus mastigodes            Large intestine

CATTLE

  Species                      Organ
Strongylus convolutus        Abomasum
Ascaris vituli               Small intestine (calves)
Strongylus ventricosus       Small intestine
Oesophagostomum inflatum     Large intestine
Trichocephalus affins        Large intestine
Strongylus micrurus          Bronchi
Strongylus pulmonaris        Bronchi

SHEEP

  Species                      Organ
Haemonchus contortus         Abomasum
Ascaris ovis                 Small intestine
Strongylus filicollis        Small intestine
Oesophagostomum columbianum  Intestines
Uncinaria cernua             Small intestine
Trichocephalus affins        Large intestine
Strongylus filaria           Bronchi
Strongylus rufescens         Bronchi and air follicles

SWINE

  Species                      Organ
Ascaris suis                 Intestines
Oesophagostomum dentatum     Large intestine
Trichocephalus crenatus      Large intestine
Trichina spiralis            Muscles and intestines
Strongylus paradoxus         Trachea and bronchi
Sclerostoma pingencola       Renal fat and kidney

POULTRY

  Species                      Organ
Ascaris inflexa              Intestine
Spiroptera hamulosa          Gizzard
Heterakis papillosa          Caecum
Syngamus trachealis          Trachea and bronchi

INTESTINAL WORMS OF SOLIPEDS.--The large round-worms or ascarides and the
sclerostomes are the most injurious intestinal parasites of solipeds. The
_A. megalocephala_ or large round-worm is from 5 to 15 inches (12 to 35
cm.) long. It may be present in the double colon in such large numbers as
to form an entangled mass that completely fills a portion of the loop in
which it is lodged. It may interfere with digestion by obstructing the
passage of alimentary matter, and irritating the intestine.

The _S. equinum_ and _S. tetracanthum_ are small worms. The former
sclerostoma is from 0.6 to 1.5 inches (18 to 35 mm.) long, and the latter
is from 0.5 to 0.6 inch (8 to 17 mm.) long. Both sclerostomes attach
themselves to the lining membrane of the intestine by their mouth parts,
and suck blood. The young _S. equinum_ may live in tumor-like cysts that
they cause to form in the lining membrane of the intestine. The young worm
may penetrate the wall of a small blood-vessel as well, and drift into a
large vessel, where it may become lodged and undergo partial development.
The irritation to the blood-vessel results in an inflammation and dilation
of the vessel wall. This is termed verminous aneurism. A portion of the
fibrin-like lining of the aneurism may flake off and drift along in the
blood stream, until finally a vessel that is too small for the floating
particle or embolus to pass through is reached. The vessel is then plugged
or a thrombus is formed. If the vessel involved by the thrombus happens to
be a mesenteric vessel, then a loop of intestine has its blood supply cut
off, and colicky pains result. Such colics are dangerous, and may terminate
fatally. Intestinal obstruction, thrombo-embolic colics, unthriftiness and
a weakened, anaemic condition may be caused by intestinal worms.

_The treatment_ is both preventive and medicinal. The preventive treatment
consists in giving young, growing animals the best care possible.
Cleanliness about the stable, giving the colt plenty of range when running
in a pasture, and feeding a ration that is sufficient to keep the colt in
good physical condition are the important preventive measures. Tartar
emetic in one-half to one dram doses may be given with the feed daily until
five or six doses are given. Turpentine may be given in one to three ounce
doses in a pint of linseed oil. This may be repeated daily for two or three
days. Worms located in the posterior bowel may be removed by rectal
injections of a weak water infusion of quassia chips. The rectum should be
first emptied with the hand, and the nozzle of the syringe carried as far
forward with the hand as possible. The injections should be repeated daily
for several days.

INTESTINAL WORMS OF CATTLE.--Intestinal worms seldom cause serious losses
from unthriftiness or death in cattle. It is in calves only that we are
called on to treat this class of disease. The symptoms resulting from the
invasion of the intestinal tract by the different worms vary in severity
according to the number, habits of the parasite and care that the animal
receives. The usual symptoms are unthriftiness, indigestion, diarrhoea and
a stunted, anaemic condition. Stiles reported extreme anaemia,
unthriftiness and many deaths among cattle in a certain section of Texas,
due to extensive infection with the _Uncinaria radialus_.

_The treatment_ is largely preventive. Calves and yearlings should be
provided with plenty of feed at all seasons of the year. Good care and
careful feeding will keep them in a thrifty, healthy condition and enable
them to throw off invasions of intestinal worms. Turpentine is the
vermifuge usually administered to calves. The dose is from two to four
drams given in a milk or raw linseed oil emulsion.

STOMACH WORM OF SHEEP.--The twisted stomach worm, _Haemonchus contortus_,
is the most injurious internal parasite of sheep. It is a very small,
hair-like worm from 0.4 to 1 inch (9 to 25 mm.) in length. In the adult
form it attaches itself to the mucous membrane of the fourth stomach or
abomasum, and lives by sucking blood. The blood present in the digestive
tract of the worm gives it a brown color, and the white oviducts which are
wound around the digestive canal cause the body to appear twisted. When the
twisted stomach worm is present in large numbers, the worms become mixed
with the contents of the stomach and can be readily found on making a
post-mortem examination.

_Symptoms of stomach worms_ are first manifest in the lambs (Fig. 76). It
is not until early summer that the disease appears in the flock. The
symptoms are not characteristic unless we consider an unthrifty, anaemic,
weak, emaciated condition accompanied by diarrhoea, during the summer
months characteristic of stomach-worm disease. The sick animals are unable
to keep up with the flock, and they like to stand about in the shade. They
move slowly, the back is arched, the appetite poor, the mucous membranes
and skin are pale and the hind parts soiled by the diarrhoeal discharge.
More acute symptoms than the above sometimes occur. The disease may last
from a few days to several weeks. A large percentage of the affected
animals die.

[Illustration: FIG. 76.--Lamb affected with stomach worm disease.]

The _treatment_ is largely preventive. Frequent changing of pastures and
dry lot feeding are common preventive measures. Permanent sheep pastures
lead to heavy losses from stomach worm disease. A very effective preventive
measure, as we may term it, is the practice of administering a vermifuge to
the ewes in the late summer and again in early winter. This may be given in
a drench, or with the feed. This prevents the reinfection of the pastures
every spring, and the young lambs are not exposed to this form of
infection. The most effective treatment that the writer has ever used is
the following formula recommended by Dr. Law: Arsenous acid one dram,
sulfate of iron five drams, powdered areca nut two ounces, common salt four
ounces. This is sufficient for one dose for thirty sheep. It may be given
with the salt, or in ground feed. If the flock is apparently healthy, four
doses given at intervals of three days is sufficient. If symptoms of
stomach worms are manifested the animals should be dosed daily until they
have received from five to ten doses, depending on the condition of the
animal.

INTESTINAL WORMS OF SHEEP.--The most widely distributed and seemingly most
injurious intestinal worm of sheep is the _OEsopliagostomum columbianum_.
It is a small worm from 0.5 to 0.75 inch (12 to 18 mm.) long. It penetrates
the lining membrane of the intestines and encysts in the intestinal wall. A
tumor, varying in size from that of a millet seed to a hazelnut, then forms
in the wall of the intestine. These tumors undergo a cheesy degeneration,
and when mature, may appear as greenish, cheesy-like masses, covering a
large portion of the lining membrane of the intestine. Diarrhoea and
emaciation may result. These symptoms are most evident during the winter
months.

_The treatment_ recommended for ridding sheep of this intestinal worm is
largely preventive. Very little can be done with the medicinal treatment of
a sheep whose intestinal tract is badly infested with this parasite. Good
care and the feeding of a proper ration are the only curative measures that
are effective in such cases. The occasional administration of a vermifuge
for the purpose of ridding the digestive tract of worms, together with the
frequent changing of pastures during the spring and summer, are the most
effective preventive lines of treatment. The same treatment recommended for
stomach worms may be used for this disease.

INTESTINAL PARASITES OF HOGS.--The _Ascaris suis_ or _common round_ worm is
very commonly found in the small intestine. It is quite frequently found in
large numbers, almost filling the lumen of the intestine of an unthrifty
pig (Fig. 75). It may also work its way into the bile duct. Sometimes,
after a hog has died, this parasite migrates forward into the stomach and
gullet. The _A. suis_ is from 4 to 10 inches (10 to 26 cm.) long.

_The Echinorhynchus gigas_ or _thorn-headed_ worm is the most dangerous of
all intestinal worms (Fig. 74). It is usually found with its proboscis or
thorn imbedded in the wall of the small intestine. The Echinorhynchus is
not as common a parasite as the Ascaride, and it is not usually present in
large numbers. Usually, not more than a half-dozen of these worms are found
in the intestine of a hog, but in some localities and in hogs that are
allowed to root around manure piles and in clover pastures the herd may
become badly infected with them and serious losses occur. The average
length of the male is about 3 inches (8 cm.) and the female 10 inches (26
cm.).

[Illustration: FIG. 77.--Whip-worms attached to wall of intestine.]

[Illustration: FIG. 78.--Pin-worms in intestine.]

The _Trichocephalus crenatus_ or _whip worm_ (Fig. 77) is slender or
hair-like in its anterior two-thirds and thick posteriorly. It is from 1.5
to 2 inches (40 to 45 mm.) long. It is found in the caecum attached to the
wall by the hair-like portion.

The _OEsophagostomum dentatum_ or _pin worm_ is from 0.3 to 0.6 inch (8 to
15 mm.) long. It is found in the large intestine (Fig. 78).

The _symptoms_ of intestinal worms are not very evident in the average
drove of hogs. None of the other farm animals are such common hosts for
intestinal worms as hogs. But it is only in extreme cases of infection by
intestinal worms, and in stunted and poorly-cared-for hogs, that very
noticeable symptoms of disease are manifested. We must not take from the
above statement that it is unnecessary to resort to treatment unless in
exceptional cases. Intestinal worms interfere with the growth of young
hogs, and may irritate and inflame the intestine, causing chronic
indigestion, nervous symptoms, and in some cases death. This irritated and
inflamed condition of the intestine is best noted in the abattoir by the
ease with which the wall of the intestine that contains large numbers of
worms tears when handling it.

_The treatment_ of intestinal worms in hogs is both preventive and
medicinal. If the conditions in the pens and houses are such as to enable
the eggs and embryos to live for a long time, or the surroundings are
favorable for infection of the animals through their feed and water supply,
the herd may become badly infested with intestinal parasites. The
preventive treatment consists in keeping hogs in clean, well-drained yards
or pastures, and feeding them from clean troughs and concrete feeding
floors that can be washed, when necessary, in order to keep them clean.
Turpentine, given in a milk emulsion, is a common remedy for intestinal
worms in hogs. The dose is one teaspoonful for every eighty pounds weight.
This dose should be repeated daily for three days. The following vermifuge
can be recommended: Santonin three to five grains, calomel five to eight
grains. This is sufficient for one hundred pounds weight. If the pigs are
small and it requires two or three to weigh one hundred pounds, the large
dose should be given. If the hogs weigh one hundred pounds or more, they
should receive the small dose. The drove should be divided into lots of ten
or fifteen hogs each. The drugs should be mixed and divided into the same
number of powders as there are lots of hogs. Ground feed is placed in the
trough, dampened with milk, or water and the powder sprinkled evenly over
it. The hogs are then allowed to eat the feed. It is best to dose them in
the morning after they have been off feed for ten or twelve hours.

VERMINOUS BRONCHITIS IN CALVES.--The lung worms of cattle, _Strongylus
micrurus_ and _Strongylus pulmonaris_, may cause heavy losses in calves and
yearlings. Older cattle may harbor these parasites, but they do not seem to
be inconvenienced by them. The _S. micrurus_ is from 1 to 3 inches (25 to
75 mm.) long. The _S. pulmonaris_ is smaller. It is from 0.4 to 1.3 inches
(10 to 35 mm.) long. They are found in the trachea and small bronchial
tubes, where they are mixed with mucous secretions from the inflamed lining
membrane of the bronchial tubes.

Wet seasons and low, wet pastures are said to favor the development of lung
worms. Their life history is not fully understood. They do not persist
generation after generation in the air passages of an animal, but the eggs
and embryos are expelled and live for a time outside of the animal, when
they may again become parasites of another or the same host.

_The symptoms_ are the same as occur in bronchitis and pneumonia. Calves
and yearlings are the only animals in the herd that may show symptoms of
the disease. The air passages become irritated and inflamed, and the calf
shows a slight cough. As the inflammation increases and the worms and
mucous secretions plug up the small bronchial tubes, the coughing spells
become more severe and rattling, wheezing sounds may be heard on
auscultating the lungs. The calf finally loses its appetite, becomes
emaciated and weak, and wanders off alone. It is usually found lying down
and shows labored breathing that is occasionally interrupted by paroxysmal
coughing. The death rate in poorly-cared-for herds is heavy.

VERMINOUS BRONCHITIS AND PNEUMONIA OF SHEEP.--The two lung worms of sheep
are the _Strongylus filaria_ and Strongylus_ rufescens_. The former is from
1.3 to 3 inches (33 to 80 mm.) long, and the latter from 0.6 to 1 inch (16
to 25 mm.) long. The _S. filaria_ is thread-like and the _S. refuscens_
hair-like in appearance. For this reason they are termed thread and hair
lung-worms. The thread-worm is found in the trachea and the larger
bronchial tubes, and the hair-worm in the most minute as well as the larger
bronchioli.

This disease is most common in wet seasons. Undrained pastures and ponds
are said to favor the spread of the disease. Permanent pastures favor the
reinfection of the flock from year to year. The eggs and embryos are
expelled in coughing, and live for a time in the pastures, pens and houses.
The sheep become infected through the dust, drinking water or feed.

_The symptoms of verminous bronchitis_ and pneumonia are quite
characteristic. Lambs suffer most from these diseases. A number of animals
in the flock are affected. Coughing, rapid and labored breathing, loss of
appetite, emaciation and weakness are the usual symptoms noticed. When a
paroxysm of coughing occurs, considerable mucus is expelled. An examination
of the expectorations may result in finding a few lung worms. In
poorly-cared-for flocks, and when complicated by stomach and intestinal
worms, the death rate is usually heavy.

_The treatment_ of lung-worm diseases in lambs and calves is largely
preventive. We should use every possible precaution against introducing the
infection into the herd or flock. It is not advisable to bring animals from
an infected herd onto the premises, without subjecting them to a careful
examination and a long quarantine before allowing them to stable or pasture
with the other animals. Calves or lambs that show marked symptoms of
disease should be given comfortable quarters, and special care and feeding.
The entire herd or flock must be given the best care and ration possible.
This is the only satisfactory method of treatment. Changing the pasture or
lot frequently may help in ridding the premises of the infection.

VERMINOUS BRONCHITIS IN HOGS.--The lung worm, _Strongylus paradoxus_, is a
common parasite of young hogs. It is from 0.6 to 1.6 inches (16 to 40 mm.)
long. When the infection is light, the worms are found mostly in the
bronchial tubes of the margin and apex of the lung.

Infection with this parasite does not depend on the humidity of the soil,
or low, wet pastures containing ponds. Probably dusty quarters are
responsible in large degree for this disease.

_The symptoms are most evident_ in pigs weighing from forty to eighty
pounds. The first symptom is a cough, occurring on leaving the bed, after
exercise and after eating. In badly infected cases the paroxysm of coughing
is quite severe. The appetite usually remains good and the thriftiness of
the pig is not seriously interfered with. The feeding of a suitable ration,
and the good care that is usually given young hogs, are responsible for the
mildness of the disease.

The treatment that is of most importance is clean quarters, and the feeding
of a ration that will keep the pig growing and healthy. The sleeping
quarters should be kept free from dust. Disinfectants should be used freely
about the quarters.

THE KIDNEY WORM OF HOGS.--_Sclerostoma pinguicola_ is the kidney worm of
hogs. It is from 1 to 1.5 inches (25 to 27 mm.) long, and when seen against
the kidney fat it appears dark or mottled. It is usually found in the fat
in the region of the pelvis of the kidney. Although the kidney worm is
capable of causing inflammatory changes in the tissues surrounding the
kidney and the pelvis of this organ, the disease cannot be determined by
any noticeable symptom. Paralysis of the posterior portion of the body is
attributed to the presence of kidney worms by stockmen. There are no data
by which we may prove that the kidney worm is responsible for this
disorder.

_The treatment_ is preventive. Clean feed, pens, watering troughs and
feeding floors are the preventive measures indicated here. It is useless to
attempt treatment with drugs, as the worms are out of reach of any drug
that may be administered.

WORMS OF THE DIGESTIVE TRACT OF POULTRY.--Poultry are often seriously
infested with worms. A small number of the less injurious worms may not
cause any appreciable symptoms of disease; but the fowl that harbors them
is a source of infection to the other fowls. The infectious nature of
parasitic disease caused by worms should be recognized more fully than at
present by poultrymen.

The different species of poultry are hosts for many different species of
round-worms, thorn-headed worms and tapeworms. Dr. Kaupp states that
_Acaris inflexa_ or large round-worm, _Heterakis pipilosa_ or small
round-worm, and the _Spiroptera hamulosa_ or gizzard-worm are frequently
found in fowls. The common round-worm may be found in the first portion of
the intestine, and the small round-worm in the caecum. Neither of the
species are dangerous unless present in large numbers. They may then
obstruct the intestine, and irritate the intestinal mucous membrane. This
may cause constipation, catarrhal inflammation of the intestine and
diarrhoea. The gizzard-worm is the most dangerous of the parasites
mentioned. The gizzard has an important digestive function, and any
condition that may weaken its muscular walls may cause serious digestive
disorders. This parasite may encyst in the wall of the gizzard.

_The treatment_ of intestinal worms in poultry is both preventive and
curative. The preventive measures consist in keeping the houses and runs
clean. Air-slaked lime should be scattered over the runs every few weeks.
The drinking places should be cleaned and disinfected daily. All possible
precautions should be taken in order to prevent filth from getting into the
drinking water. Epsom salts, powdered areca nut and santonin are the
remedies commonly recommended for the treatment of intestinal worms. From
twenty to forty grains of Epsom salts may be given. Powdered areca nut is
recommended in from three to ten grain doses. Santonin may be given in from
one to two grain doses. Both the areca nut and santonin may be given with
the feed.

THE GAPES IN BIRDS.--The gape-worm, _Syngamus trachealis_, is from 0.2 to
0.8 inch (5 to 20 mm.) long. The male and female are permanently united.
The male is about one-third as long as the female, and when attached to the
anterior third of the female, gives the pair a forked appearance.

Fowls become infested with the gape-worm by eating the adult parasite that
has been expectorated, or an earth worm that is host for the immature
parasite. The embryo gape-worm is freed in the intestine, and from here
they are supposed to migrate into the abdominal air sacs and to the trachea
and bronchi.

_The symptom_ are most severe in very young fowls. The affected bird opens
its mouth and appears to gasp for breath, sneeze and attempt to swallow. In
the severe cases the appetite is interfered with, mucus accumulates in the
mouth and the bird is dull and listless. The death rate is quite high in
young-chickens and turkeys.

_The treatment_ is both preventive and curative. If the gape-worm is known
to be present in the runs, the ground should be covered with lime, and the
fowls moved to fresh runs if possible. The young birds should not be
exposed to the infection until they are well feathered out. Antiseptics may
be given with the drinking water. Disinfectants should be used freely about
the poultry houses, and the quarters kept clean. The worms may be snared by
inserting a stiff horse hair that has been twisted and forms a loop into
the trachea. This may be dipped into camphorated oil or turpentine. This
treatment should be repeated until the bird has been relieved.


QUESTIONS

1. Name the different groups of internal parasites; give examples of each.

2. What conditions favor liver rot? Give the life history of the liver
   fluke.

3. Name three common tapeworms; give the life history of the beef and pork
   tapeworms.

4. Name the common intestinal worms of horses and give the treatment.

5. Give the symptoms and treatment of stomach-worm disease of sheep.

6. Name the common intestinal worms of hogs and give treatment.

7. What species of domestic animals suffer most of verminous bronchitis?
   Give the treatment.

8. Name the common internal parasites of poultry and give treatment.



PART VI.--INFECTIOUS DISEASES



CHAPTER XXVI

HOG-CHOLERA


HOG-CHOLERA is a highly infectious disease of swine. It is characterized by
an inflammation, of the lymphatic glands, kidneys, intestines, lungs and
skin. The inflammation is hemorrhagic in character, the inflamed organs
usually showing deep red spots or blotches.

Hog-cholera is especially prevalent in the corn-raising States which
possess a denser hog population than any other section of the United
States. In this country the loss from hog-cholera in 1913 amounted to more
than $60,000,000, and it may be considered of greater economic importance
than any of the other animal diseases.

SPECIFIC CAUSE.--The specific cause of hog-cholera is an _ultra-visible
organism_ that is present in the excretions, secretions and tissues of a
cholera hog. De Schweinitz and Dorset in 1903 produced typical hog-cholera
by inoculating hogs with cholera-blood filtrates that were free from any
organism that could be demonstrated by microscopical examination or any
cultural method. The term ultra-visible virus is applied to the virus of
hog-cholera.

_The ultra-visible virus_ is eliminated from the body of the cholera hog
with the body secretions and excretions. Healthy hogs contract the disease
by eating feed or drinking water that is infected with the virus. There are
other methods of infection, but field and experimental data show that
hog-cholera is commonly produced by taking the germs into the body with
food and drinking water.

ACCESSORY CAUSES.--The usual method of introducing hog-cholera into a
neighborhood is through the importation of feeding or breeding hogs that
were infected with the disease before they were purchased, or became
infected through exposure to the disease in the public stock-yards and
stock-cars. The shipping of feeding hogs from one section of the country to
another, and from public stock-yards, has always been productive of
hog-cholera. Dr. Dorset states that more than fifty-seven per cent of the
hog-cholera outbreaks are caused by visiting, exchanging work, exposure on
adjoining farms and harboring the infection from year to year (Fig. 79),
and more than twenty-three per cent to purchasing hogs and shipping in
infected cars, birds and contaminated streams.

[Illustration: FIG. 79.--A hog yard where the disease-producing germs may
be carried over from year to year.]

In neighborhoods where outbreaks of hog-cholera occur necessary precautions
against the spread of the disease are not taken. The _exchange of help_ at
threshing and shredding time in neighborhoods where there is an outbreak of
hog-cholera is the most common method of spreading the disease. _Visiting
farms_ where hogs are dying of cholera; walking or driving a team and wagon
through the cholera-infected yards; stock buyers, stock-food and
cholera-remedy venders that visit the different farms in a neighborhood may
distribute the hog-cholera virus through the infected filth that may adhere
to the shoes, horses' feet and wagon wheels. _Cholera hogs_ may carry the
disease directly to a healthy herd when allowed to run at large. _Streams_
that are polluted with the drainage from cholera-infected yards are common
sources of disease.

_Pigeons, dogs, cows_ and _buzzards_ that travel about the neighborhood and
feed in hog yards and on the carcasses of cholera hogs may distribute the
disease. Because of the active part that dogs, birds and surface drainage
take in the distribution of hog-cholera, the practice of allowing the
carcasses of dead hogs to lie on the ground and decompose is responsible
for a large percentage of the hog-cholera outbreaks.

_Age_ is an important predisposing factor. Young hogs are most susceptible
to cholera, and this susceptibility can be greatly increased by giving them
crowded, filthy quarters. Infection with lice, lung and intestinal worms,
the feeding of an improper ration and sudden changes in the ration lower
the natural resistance of a hog against disease. Pampered hogs usually
develop acute cholera when exposed to this disease.

Hog-cholera is more virulent or acute during the summer and fall months
than it is during the winter and spring months. After the disease sweeps
over a section of country, it becomes less virulent and takes on a subacute
or chronic form. Outbreaks of hog-cholera usually last two or three years
in a neighborhood. This depends largely on the number of susceptible hogs
that were not exposed to the infection the first season, and the preventive
precautions observed by the owners.

PERIOD OF INCUBATION.--The length of time elapsing between the exposure of
the hog to the cholera virus, and the development of noticeable symptoms of
hog-cholera, varies from a few days to two or three weeks. The length of
this incubation period depends on the susceptibility of the animal, the
virulence of the virus and the method of exposure. An acute form of
hog-cholera indicates a short period of incubation, and a chronic form, a
long period.

SYMPTOMS.--The symptoms of hog-cholera may differ widely in the different
outbreaks of the disease. The symptoms may be classified under the
following forms: Acute, subacute and chronic. The acute form of hog-cholera
is the most common. The early symptoms are tremors, fever, depressed
appearance, marked weakness, staggering gait, constipation and diarrhoea,
labored breathing and convulsions. Death may occur within a few hours or a
few days. Recovery seldom occurs. In the subacute form, the symptoms are
mild and develop slowly. Recovery may take place within a few days, or
after extending over a week or ten days it may assume the chronic form.
Very often in outbreaks of subacute cholera a large majority of the herd
does not show visible symptoms of the disease. In the chronic form, marked
symptoms of pleuropneumonia and chronic inflammation of the intestine are
common. Ulcers and sores form on the skin and the hair may come off. Large
portions of the skin may become gangrenous and slough. Young hogs are
usually stunted and emaciated.

_The first symptom_ of disease is an elevation of body temperature.

At the beginning of any outbreak of hog-cholera the _body temperatures_ of
the apparently healthy animals may vary from 105\260 to 108\260 F. After
a few days, animals that are fatally sick or recovering from the disease
may show normal or subnormal body temperature.

_Loss of appetite_ is the first symptom of disease usually noted by the
person in charge of the herd. The hog may show a disposition to eat dirt.
The sick hog is usually found lying in its bed, or off by itself in a quiet
place. It presents a rather _characteristic appearance_. The back is
arched, the hind feet are held close together, or crossed, the abdomen is
tucked up and the hog appears weak in its hind parts. _Diarrhoea_ or
_constipation_ may be present. The color of the diarrhoeal discharges
varies according to the character of the feed, and it may be more or less
tinged with blood and have a disagreeable odor. The urine is highly
colored.

_The respirations and pulse beats_ are quickened and abnormal in character.
Thumps sometimes occur. When the mucous membranes lining the throat and
anterior air passages are thickened, the respirations are noisy and
difficult. The animal may cough on getting up from its bed and moving
about. There is at times a noticeable discharge from the nostrils. When the
_lungs_ are inflamed the respirations are quickened and labored. In case
the pleural membrane is inflamed, the respiratory symptoms are more severe,
and the hog shows evidence of pain when the walls of the chest are pressed
on. The _pericardium_ may be inflamed. In such cases the hog staggers and
falls when forced to walk.

_The central nervous system_ may be involved by the inflammation. The usual
symptoms occurring in inflammation of the brain and its coverings are then
present. A sleepy, comatose condition may end in death, or the animal dies
in a convulsion.

_The secretions of the skin_ and mucous membranes are abnormal. The skin in
the regions of the ears, inside of the thighs and under surface of the body
is moist, dirty or discolored red. Just before death the skin over the
under surface of the body becomes a purplish red. In the chronic form, a
dirty, thickened, wrinkled skin is commonly observed. At first the
secretion from the eyes is thin and watery, but it becomes thick, heavy and
pus-like, causing the margins of the lids to adhere to each other.

The death rate in hog-cholera varies in the different forms of the disease.
The average death rate is about fifty per cent.

DIFFERENTIAL DIAGNOSIS.--The diagnosis of hog-cholera in the field must
depend on the clinical symptoms, post-mortem lesions and history of the
outbreak. The history should be that of a highly infectious disease.

[Illustration: FIG. 80.--Carcass of a cholera hog showing different groups
of lymphatic glands; kidneys; and ulcer on caecum.]

_Abnormal body temperatures_ of a large percentage of the herd indicate the
presence of an acute infectious disease. We should then destroy one of the
sick hogs and make a careful post-mortem examination (Fig. 80). An early
diagnosis of the disease is necessary, as this enables us to use curative
treatment when it will do some good, and take the necessary steps toward
preventing the spread of the disease to neighboring herds.

_Intestinal and lung worms_ are common in young hogs. The presence of these
worms does not always indicate that they are the cause of the sickness and
death of the animal. Such parasites are injurious and may cause disease,
but it is only in rare cases that they cause death.

"_Pig typhoid_" is sometimes spoken of as a highly infectious disease
involving the intestines. A disease of hogs that may be termed typhus-fever
sometimes affects a large number of the hogs in the herd. This disease
occurs among hogs kept in small yards and houses that are crowded,
unsanitary and in continuous use, or when the hogs drink from wallows,
ponds and creeks.

The term swine-plague should not be used in speaking of outbreaks of
hog-cholera, as it is now considered a form of hog-cholera involving
especially the lungs.

[Illustration: FIG. 81.--Kidneys from hog that died of acute hog-cholera.]

[Illustration: FIG. 82.--Lungs from hog that died of acute hog-cholera.]

LESIONS.--In _acute hog-cholera_ the inflammation is hemorrhagic in
character. Small, red spots and blotches occur in different organs and
tissues. In the _chronic form_ of the disease ulceration of the intestinal
and gastric mucous membrane, inflammation of the lungs and pleura and
sloughing of the skin are common lesions.

_The skin_ over the under side of the neck, body and inside of the thighs
may appear red or purplish-red in color. The different groups of _lymphatic
glands_ are enlarged and softened. They may vary in color from a
grayish-red to a deep red, depending on the degree of engorgement with
blood. The pleura and pericardium may show small red spots and blotches.
The _kidneys_ are usually lighter colored than normal, and marked with red
spots and blotches (Fig. 81). The _spleen_ may show no evidence of disease.
It may be large and soft, or even smaller than normal. The _liver_ may be
enlarged and dark, or mottled and light colored.

The _stomach_ and _intestines_ may show hemorrhagic spots and blotches.
Sometimes the gastric and intestinal mucous membrane is a brick red.
Ulceration of the mucous membrane is common (Fig. 83).

[Illustration: FIG. 83.--A piece of intestine from a hog that died of
chronic hog-cholera, showing appearance of intestinal ulcers.]

Small, red spots may be present on the surface of the _lungs_ (Fig. 82).
Scattered lung lobules or a large portion of the lungs may be inflamed. In
chronic hog-cholera, pleural exudation, adhesions and abscesses in the lung
tissue may occur. Inflammations of the pericardium and heart muscle are
less common lesions.

PREVENTIVE MEASURES.--Hog-cholera is the most widespread infectious disease
of hogs, and all possible precautions against its distribution to healthy
herds should be practised. Hogs coming from other herds and stock shows
should be excluded from the home herd until they are positively shown to be
free from disease. They should be quarantined in yards set off for this
purpose. The hogs should be cleaned by dipping or washing them with a
disinfectant. The quarantine period should be longer than the average
period of incubation. Three weeks is sufficient.

_The possible introduction of the disease_ into the pens by people, dogs,
birds and other carriers of the disease should be guarded against,
especially if cholera is present in the neighborhood. The exchange of help
at threshing and shredding time with a neighbor who has hog-cholera on his
farm is a common method of distributing the infection. It is not advisable
to allow a stranger to enter your hog-houses and yards, unless his shoes
are first disinfected. Whenever it is necessary for a person to enter yards
where the disease is present, the shoes should be cleaned and disinfected
on leaving. The wheels of wagons, and the feet of horses that are driven
through cholera yards, should be washed with a disinfectant. The feet of
feeding cattle that are shipped from stock-yards should be treated in the
same manner. Persons taking care of cholera hogs should observe the
necessary precautions against the distribution of the disease, and see that
others practise like precautions.

Hog-yards should be well drained and all wallow holes filled. Pens and
pastures through which the drainage from the swine enclosures higher up
flows should not be used for hogs.

CARE OF A DISEASED HERD.--When an outbreak of hog-cholera occurs on a farm
the farm should be quarantined. The herd should be moved away from running
streams, public roads and line fences, so that neighboring herds are not
unnecessarily exposed to the disease. During the hot weather shade and an
opportunity to range over a grass lot or pasture are highly necessary. A
recently mowed meadow, or a blue grass pasture and a low shed, open on all
sides and amply large for the herd to lie under, give the animals clean
range and comfortable, cool quarters. Roomy, dry, well-ventilated
sleeping-quarters that are free from drafts and can be cleaned and
disinfected are best when the weather is cold and wet.

In the subacute, and in the early part of an acute outbreak of hog-cholera,
it is advisable to separate the sick from the well hogs. The fatally sick
animals should be destroyed.

[Illustration: FIG. 84.--Cleaning up a hog lot.]

A very light ration should be fed and an intestinal antiseptic given with
the feed. A thin slop of shorts is usually preferred. Four ounces of
pulverized copper sulfate may be dissolved in one gallon of hot water, and
one quart of this solution may be added to every ten gallons of drinking
water and slop. Water and slop should not be left in the troughs for the
hogs to wallow in. The troughs should be disinfected and turned bottom side
up as soon as the hogs have finished feeding and drinking. Kitchen slop and
sour milk should not be fed. The care and treatment of the herd require
work and close attention on the part of the attendant. Indifferent,
careless treatment is of no use in this disease.

A disinfectant should be sprayed or sprinkled about the feed troughs,
floors, pens and sleeping quarters daily.

DISPOSING OF DEAD HOGS.--The carcasses of the dead hogs should be burned.
Before placing the carcass on the fire, it should be cut open and several
long incisions made through the skin. A crematory may be made by digging
two cross trenches that are about one foot deep at the point where they
cross, and shallow at the ends. Iron bars or pipe may be laid over the
trenches where they cross for the carcass to rest upon, or woven wire
fencing securely fastened with stakes may be used in the place of the iron
bars. If the carcass is disposed of by burying, it should be buried at
least four feet deep and covered with quicklime.

DISINFECTING THE YARDS AND HOUSES.--If the sick hogs are moved to new
quarters at the beginning of the outbreak, the hog houses and yards should
be cleaned and disinfected (Fig. 84). The manure and all other litter
should be hauled away to a field where there is no danger from this
infectious material becoming scattered about the premises, leaving a centre
of infection in the neighborhood and causing outbreaks of cholera among
neighboring herds. It may be advisable to burn the corn-cobs and other
litter that have accumulated about the yards. Loose board floors should be
torn up and the manure from beneath removed. Portable houses should be
removed. The floors, walls of the house and fences should be first cleaned
by scraping off the filth, and then sprayed with a three per cent water
solution of a cresol or coal tar disinfectant to which sufficient lime has
been added to make a thin whitewash. Three or four months of warm, sunny
weather are sufficient to destroy the cholera infection in well-cleaned
yards.

ANTI-HOG-CHOLERA SERUM.--The credit of developing the first and at present
the only reliable anti-hog-cholera serum and method of vaccination belongs
to Drs. Dorset and Niles. Anti-hog-cholera serum came into general use in
1908, and all of the swine-producing States have established State
laboratories for the production of this serum.

Anti-hog-cholera serum is produced by injecting directly, or indirectly,
into the blood-vessels of an immune hog a large quantity of cholera virus,
secured by bleeding a hog that is fatally sick with acute cholera, and
bleeding the injected animal after it has completely recovered from the
injection. The injection of the cholera blood is for the purpose of
stimulating the production of antibodies by the body tissues, and raising
the protective properties of the immune hog's blood. An animal so treated
is called a hyperimmune (Fig. 85). The blood from the hyperimmunes is
defibrinated and a preservative added, and after it has been tested for
potency and freedom from contaminating organisms, it is ready for use.

[Illustration: FIG. 85.--Hyperimmune hogs used for the production of
anti-hog-cholera serum.]

THE VACCINATION OF HOGS WITH ANTI-HOG-CHOLERA SERUM.--The vaccination of a
hog by the single method consists in injecting hypodermically or
intramuscularly anti-hog-cholera serum. The immunity conferred may not last
longer than three or four weeks.

The vaccination of a hog by the _double method_ consists in injecting
hypodermically or intramuscularly anti-hog-cholera serum and hog-cholera
blood.

_The vaccination or treatment_ of a cholera hog showing noticeable
symptoms, or a high body temperature, consists in injecting hypodermically
or intramuscularly anti-hog-cholera serum (Fig. 87).

[Illustration: FIG. 86.--Preparing the hog for vaccination by washing the
part where the serum is injected with a disinfectant.]

[Illustration: FIG. 87.--Vaccinating a hog.]

_The region_ into which the serum and cholera blood may be injected are the
inside of the thigh, within the arm, flank and side of the neck (Fig. 86).
Two hypodermic syringes, holding about twenty cubic centimetres and six
cubic centimetres, and having short, heavy, seventeen or eighteen-gauge
slip-on needles, should be used. The small syringe is used for injecting
the virulent or cholera blood which is injected into a different part than
the serum. The quantity of serum and virus injected varies with the size
and condition of the animal. _Young hogs_ should receive one-half cubic
centimetre of serum for each pound of body weight, and _cholera hogs_
should be given one-half more to twice the dose that is recommended for
healthy animals. The dose of virus recommended varies from one to two cubic
centimetres for each hog.

In vaccinating _small pigs_ not more than five, and in large hogs not more
than twenty, cubic centimetres should be injected at any one point. The
_body temperature_ of each animal should be taken. A body temperature of
103.5\260 F. in a mature hog and a body temperature of 104\260 F. in a
young hog may indicate hog-cholera. Exercise, feeding and close
confinement in a warm place may raise the body temperature above the
normal.

Hogs that are to be vaccinated or treated should not be given feed for at
least twelve hours before handling them. If possible they should be
confined in a roomy, clean, well-bedded pen. If this is practised, they are
cleaner and easier to handle and their body temperatures are less apt to
vary. After the treatment or vaccination the hogs should be fed a light
diet for a period of at least ten days, and the ration increased gradually
in order to avoid causing acute indigestion. This is necessary because of
the elevation in body temperature resulting from the inability of the
animal to digest heavy feeds, kitchen slops and sour milk. If poor judgment
is used in caring for the vaccinated hogs, and the person who vaccinates
them uses careless methods, heavy losses from acute indigestion, blood
poisoning, or hog-cholera may occur.


QUESTIONS

1. What is the specific cause of hog-cholera? Give and describe the
   different methods of spreading the disease.

2. What are the symptoms of hog-cholera?

3. Give the preventive and curative treatment of hog-cholera.

4. What is anti-hog-cholera serum? Give the different methods of
   vaccination and treatment.



CHAPTER XXVII

TUBERCULOSIS


[Illustration: FIG. 88.--Koch's _Bacillus tuberculosis._]

Tuberculosis is a contagious an and domestic animals, affecting any the
lymphatic glands and lungs, change in the tissues is the formation tubercle
or nodule.

HISTORY.--Tuberculosis is one of the oldest of known diseases of domestic
animals and man. Its contagious character was proven by Villemin in 1865,
who by experential infection transmitted tuberculosis from man to animals
and from animal to animal. It was in 1882 that Dr. Robert Koch discovered
and proved by inoculation experiments that the disease was caused by a
specific germ (Fig. 88). Prior to the experiments by Villemin and Koch, the
belief was that tuberculosis was due to heredity, unsanitary conditions and
inbreeding. Following discovery of the specific germ and conditions
favoring its development and spread, numerous scientifically conducted
experiments were made. These resulted in practical methods of control and
elimination of tuberculosis from herds having this disease. By carefully
conducted experiments and other forms of educational work the infectious
character of tuberculosis and the economic importance of preventative
measures have been demonstrated. The average stockman is well informed
regarding the character and economic importance of this disease, but there
is no general application of this knowledge, and tuberculosis is increasing
in dairy and breeding herds. The slow development of tuberculosis, and the
absence of visible symptoms during the early stage of the disease, are
responsible for this condition and the extensive infection of dairy and
breeding herds.

PREVALENCE OF THE DISEASE.--Tuberculosis is very prevalent among cattle and
swine in all countries where intensive agriculture is practised. It is a
rare disease among cattle of the steppes of eastern Europe and the cattle
ranges of the western portion of the United States. In countries where
dairying is an important industry, tuberculosis is a common disease of
cattle and hogs. The abattoir reports of Europe and the United States show
that tuberculosis is on the increase among domestic animals. The Bureau of
Animal Industry of the United States Department of Agriculture reports that
out of 400,008 cattle tested with tuberculin 9.25 per cent reacted. Melvin
states that the annual loss from tuberculosis in the United States is about
$23,000,000. In dairy herds in which the disease has existed for several
years, it is not uncommon to find from 25 to 75 per cent tubercular.

THE DIRECT CAUSE.--The direct cause of tuberculosis is Koch's _Bacillus
tuberculosis_. This is a slender, rod-shaped microorganisms (Fig. 88)
occurring in the diseased tissues, feces and milk of a tubercular animal.
It belongs to that small group known as acid-fast bacteria. The tubercle
bacillus is not really destroyed by external influences, and it may retain
its virulence for several months in dried sputum if protected from the
light. Its vitality enables it to resist high temperatures, changes in
temperature, drying and putrefaction to a, greater degree than most
non-spore-producing germs. Direct sunlight destroys the germ within a few
hours, but it may live in poorly lighted, filthy stables for months. A
temperature of 65\260 C. destroys it in a few minutes.

Animals that, have advanced or open tuberculosis may disseminate the germ
of the disease in the discharge from the mouth, nostrils, genital organs,
in the intestinal excreta and milk. The germs discharged from the mouth and
nostrils are coughed up from the lungs and may infect the feed. Milk is a
common source of infection for calves and hogs. Allowing hogs to run after
cattle is sure to result in infection of a large percentage of them, if
there are any open cases of tuberculosis in the herd.

PREDISPOSING CAUSES.--Any condition that may lessen the resistance of the
body or enable the tubercle bacillus to survive the exposure outside the
body favors the development of the disease and the infection of the healthy
animals. Crowded, poorly ventilated, filthy stables lower the
disease-resisting power of the animal, and favor the entrance of the germs
into the body. Under such unsanitary conditions, tuberculosis spreads
quickly among dairy cattle, and a large percentage of the animals develop
the generalized form of the disease. Sanitary stables and yards do not
prevent the spread of the disease among animals that live in close contact
with one another. Fresh air and sanitary surroundings only check the spread
and retard its progress.

INTRODUCTION OF TUBERCULOSIS INTO THE HERD.--The common method of
introducing tuberculosis into the herd is through the purchase of animals
having the disease. Such animals may be in apparent good health at the time
of purchase, and be affected with generalized or open tuberculosis.

_A source of infection_ is by unknowingly buying cows that have reacted to
the tuberculin test. The indiscriminate use and sale of tuberculin are
largely responsible for the large number of reacting animals that have been
placed on the open market. This dishonest practice has resulted in the
rapid spread of the disease in certain localities. For years a large
percentage of the breeding herds have been infected, and the writer has met
with several herds of dairy and beef cattle that became tubercular through
the purchase of tubercular breeding animals.

SYMPTOMS.--There is no one symptom by which we may recognize tuberculosis
in cattle and hogs. None of the symptoms shown by a tubercular animal are
characteristic, unless it is in the late stage of the disease. In a
well-cared-for animal, the lymphatic glands in the different regions of the
body, the lungs, liver and other organs, may be full of tubercles without
causing noticeable symptoms of disease (Fig. 89).

[Illustration: FIG. 89.--A tubercular cow. This cow was, to all
appearances, in good health, but showed generalized tuberculosis on
post-mortem examination.]

_Tuberculosis may attack any organ of the body_, and in the different cases
of the disease the symptoms may vary. Enlargement of the glands in the
region of the throat, and noisy, difficult breathing are sometimes present.
The udder frequently shows hard lumps scattered through the gland. Bloating
may occur if a diseased gland in the chest cavity presses on the oesophagus
and prevents the usual passage of gas from the paunch. Chronic diarrhoea
may occur. If the disease involves the digestive tract, the animal is
unthrifty and loses flesh rapidly. Coughing is not a characteristic
symptom, and we should not place too much emphasis on it. If the lungs
become tubercular the animal usually has a slight, harsh cough. The cough
is first noticed when the cattle get up after lying down, when the stable
is first opened in the morning and when the animals are driven. If the
chest walls are thin, soreness from pressure on the ribs may be noted. By
applying the ear to the chest wall and listening to the lung sounds,
absence of respiratory murmurs and abnormal sounds may be distinguished,
due to consolidation of the lung tissue, abscess cavities and pleural
adhesions. In a well-advanced case the hair is rough, the skin becomes
tight and the neck thin and lean. The animal may breathe through the mouth
when it is exercised. Weakness may be a prominent symptom.

[Illustration: FIG. 90.--Tubercular spleens.]

Breeding animals that are well fed and cared for may live for several years
before showing noticeable symptoms of tuberculosis. The disease progresses
more rapidly in milch cows, especially if given poor care. Calves allowed
to nurse a tubercular mother that is giving off tubercle bacilli frequently
develop enlarged throat glands and the intestinal form of the disease.

Hogs develop a generalized form of tuberculosis more quickly than cattle,
but an unthrifty, emaciated condition is seldom noted in hogs under ten
months old.

POST-MORTEM LESIONS.--The effect of the tubercle bacillus on the body is to
irritate and destroy the tissues. Lumps or tubercles form in the lymphatic
glands, liver, lungs, spleen (Fig. 90), serous membranes, kidneys and other
body organs (Figs. 91 and 92). The tubercles may be very small at first,
but as the disease progresses they continue to enlarge until finally a
tubercular mass the size of a base-ball, or larger, is formed (Figs. 93,
94, 95 and 96). Lymphatic glands may become several times larger than
normal and the liver and lungs greatly enlarged. The pleura and peritoneum
may be thickened and covered with tubercles about the size of a millet
seed, or larger. Pleural and peritoneal adhesions to the organs within the
body cavities are common.

[Illustration: FIG. 91.--The carcass of a tubercular cow. Note the
condition of the carcass, and the tubercular nodules on the chest wall,
showing that the disease was well advanced.]

[Illustration: FIG. 92.--A section of the chest wall of a tubercular cow
showing a better view of the diseased tissue.]

The tubercle usually undergoes a cheesy degeneration. Old tubercles may
become hard and calcareous. Sometimes the capsule of the tubercle is filled
with pus. A yellowish, cheesy material within the capsule of the tubercular
nodule or mass is typical of the disease.

THE TUBERCULIN TEST.--The only certain method of recognizing tuberculosis
is by this test. There is no other method of recognizing this disease that
is more accurate than the above test.

The substance used in testing animals for tuberculosis is a laboratory
product. It is a germ-free fluid prepared by growing the tubercle bacillus
in culture medium (bouillon) until charged with the toxic products of their
growth. The culture medium is then heated to a boiling temperature in order
to destroy the germs. It is then passed through a porcelain filter that
removes the dead germs. The remaining fluid is tuberculin.

[Illustration: FIG. 93.--A very large tubercular gland that had broken down
in the central portion.]

_There are two methods of applying_ the tuberculin test. The subcutaneous
test consists in injecting a certain quantity of tuberculin beneath the
skin, and keeping a record of the body temperature of the animal between
the eighth and eighteenth hours following the injection. Tubercular animals
show an elevation in temperature that comes on about the eighth or twelfth
hour of the test. In the _intradermal test_, a small quantity of a special
tuberculin is injected into the deeper layer of the skin. The seat of the
injection in cattle is a fold of the skin on the under side of the base of
the tail. In tubercular animals the injection is followed by a
characteristic local swelling.

[Illustration: FIG. 94.--A tubercular gland that is split open.]

[Illustration: FIG. 95.--Caul showing tuberculosis.]

[Illustration: FIG. 96.--Foot of hog showing tuberculosis of joint.]

The control of tuberculosis is largely in the hands of the breeder and
dairyman. This is a disease that requires the cooperation of stockmen and
sanitary officers in the application of control measures. If there are
several open cases of tuberculosis in a herd of cattle, the application of
the tuberculin test, removal of the reacting animals and disinfection of
the premises are not sufficient to eradicate the disease. It is necessary
to repeat the tuberculin test within six months, and later at twelve-months
intervals, until none of the animals that remain in the herd react.

The most practical method of disposing of dairy cows that react to the
tuberculin test is to slaughter them. Unless a large percentage of the herd
is tubercular, it is not advisable to practise segregation and quarantine.
This may be advisable if the reactor is a valuable breeding animal, unless
visible symptoms are shown. The milk from reacting cows may be used if it
is boiled or sterilized. Whenever a calf is born of a reactor, it should be
separated from the mother and fed milk from a healthy cow.

The separation of the tubercular from the healthy cows must be complete.
Separate buildings, yards and pastures that do not join the quarters where
the healthy animals are kept should be provided. The person attending the
reactors should not attend the healthy animals, and separate forks,
shovels, pails and other utensils should be provided for the two herds.

The best method of controlling tuberculosis in hogs is to slaughter all
reactors, disinfect yards and houses and move the herd. If the old quarters
are free from filth and carefully disinfected, the hogs may be returned
without danger of infection after six months. A retest of the herd should
be made before returning them to the permanent quarters and the reactors
slaughtered.


QUESTIONS

1. Give the history of the early experimental work in tuberculosis; give
   the common methods of spreading the disease.

2. What are the symptoms and post-mortem lesions in tuberculosis?

3. Give the method of controlling tuberculosis.



CHAPTER XXVIII

INFECTIOUS DISEASES COMMON TO THE DIFFERENT SPECIES OF DOMESTIC ANIMALS


SEPTICAEMIA AND PYAEMIA.--The term commonly used in speaking of simple
septicaemia and pyaemia is blood poisoning.

These infectious diseases are _caused_ by several different species of
bacteria that gain entrance to the tissues by way of wounds. The bacteria
that cause pyaemia are transferred by the blood stream to different organs
and produce multiple abscesses. In septicaemia, the bacteria may occur in
immense numbers in the blood and produce a general infection of the
tissues, causing a parboiled appearance of the liver, heart, voluntary
muscles and kidneys, and enlargement of the spleen. The two forms of
infection are often present at the same time.

[Illustration: FIG. 97.--_Staphylococcus pyogenes_.]

[Illustration: FIG. 98.--_Streptococcus pyogenes_.]

_The forms of bacteria_ that may cause blood poisoning are the
_Staphylococcus pyogenes aureus_ and _albus_ (Fig. 97), _Streptococcus
pyogenes_ (Fig. 98), _Bacillus pyocyaneus_, _Bacillus coli communis_, and
the bacillus of malignant oedema (Figs. 99 and 100). The latter is included
with the bacteria that produce blood poisoning because it is a frequent
cause of wound septicaemia. Subcutaneous, punctured, lacerated, contused
and deep wounds without suitable drainage are the most suitable for the
development of and infection of the tissues with the above germs. Wound
infection is most common during hot weather.

_The symptoms are both general and local_. The tissues in the region of the
wound become swollen and painful. In malignant oedema the swelling pits on
pressure, and if the wound is open, the surface becomes soft and may
slough. The body temperature may be several degrees above the normal, the
appetite is impaired or the animal stops eating and acts sleepy. A small
amount of highly-colored urine may be passed. Nervous symptoms, such as
muscular twitching, excited condition, delirium and paralysis, may be
noted.

[Illustration: FIG. 99.--Bacillus of malignant oedema, showing spores.]

[Illustration: FIG. 100.--Bacillus of malignant oedema.]

_The prognosis is unfavorable_. In pyaemia the animal may live from a few
days to several months. Septicaemia usually terminates fatally in from two
to ten days.

_The treatment is largely preventive_. Wounds should be given prompt
attention. They should be freed from all foreign substances and washed with
a disinfecting solution. A contused-lacerated wound should not be sutured
if this interferes with the cleansing of it, and the escape of the wound
secretions. All punctured wounds should be enlarged so as to permit of
treatment and drainage.

HEMORRHAGIC SEPTICAEMIA.--An acute infectious disease of ruminants and
swine, characterized by hemorrhages in the different body tissues that
appear as small red spots or blotches.

_The specific cause of this disease_ is the _Bacillus bovisepticus_ (Fig.
101). This bacillus probably enters the body tissues by way of the lining
membrane of the intestinal and respiratory tracts. In the northern States,
cattle pasturing on marsh lands and swampy pastures are more often affected
with the disease in the late summer and fall than at other seasons of the
year.

The drinking of contaminated surface water that collects in muddy pools and
ponds may cause the disease. Cattle pasturing in stalk fields sometimes
become infected in this way. Dusty sleeping quarters and small, crowded,
muddy yards seem to favor the development of the disease in hogs. Exposure,
insufficient exercise and careless feeding are the predisposing factors.

[Illustration: FIG. 101.--_Bacillus bovisepticus_.]

_The symptoms_ vary according to the animal and organ, or organs of the
body affected and the violence of the attack. The disease may be acute or
subacute. The brain and its membranes, lungs and air-passages and
intestines may become affected. The symptoms may be classed under the head
of nervous, respiratory and intestinal (Fig. 102), and they may be very
unsatisfactory from the standpoint of diagnosis. The history and
post-mortem lesions are of most value in the recognition of this disease.
The local conditions, the loss of several animals in the herd and the
finding of hemorrhagic lesions in the different body tissues may enable
the examiner to correctly diagnose the disease. It is very advisable in
order to confirm the diagnosis to make a bacteriological examination of the
tissues.

The acute form of the disease is very fatal. Animals that have the subacute
form usually recover. The death-rate is between five and fifteen per cent
of the herd. The mortality is heavier than this unless prompt preventive
measures are taken.

_Preventive treatment_ is of the greatest importance. Cattle that become
affected when running on pasture should be moved, or in case a part of the
pasture is swampy, we may prevent further loss by fencing off this portion.
Drinking places that are convenient and free from filth should be provided.
Watering troughs and drinking fountains should be cleaned and disinfected
every few weeks. For this purpose, use a three per cent water solution of a
cresol disinfectant, or a ten per cent water solution of sulfate of iron.
Dusty quarters should be cleaned and disinfected. Dirt floors may be
sprinkled with crude oil.

[Illustration: FIG. 102.--A yearling steer affected with septicaemia
haemorrhagica, intestinal form.]

When an outbreak of septicaemia haemorrhagica occurs in a herd, both the
well and sick animals should be given a physic. Cattle may be given
one-half pound of Epsom salts, repeated in three or four days; sheep and
hogs from one to four ounces of raw linseed oil. Animals that have the
subacute form of the disease may be given stimulants, and iron and bitter
tonics.

ANTHRAX, CHARBON.--This is an acute infectious disease affecting many
different species of animals. Anthrax is one of the oldest animal diseases,
and early in the history of the race it existed as a plague in Egypt. It
most commonly affects cattle, sheep and horses. Man contracts the disease
by handling wool and hides from animals that have died of anthrax, and by
accidental inoculation in examining the carcass of animals that have died
of the disease.

_Cause_.--Anthrax is caused by a rod-shaped, spore-producing microorganism,
_Bacillus anthracis_ (Fig. 103). It gains entrance to the body by way of
the intestinal tract, lungs and air-passages and the skin. The bites of
insects play an important part in the distribution of the disease in some
localities, but the most common method of infection is by way of the
digestive tract, through eating and drinking food and water contaminated
with the anthrax germs. The spores of the _B. anthracis_ are very resistant
to changes in temperature and drying. They may live for years in rich,
moist inundated soils. River-bottom and swampy lands that have become
infected with discharges from the bodies of animals sick with anthrax, and
by burying the carcasses of animals that have died of this disease, retain
the infection for many years. Anthrax is very widely distributed. It is the
most prevalent in the southern portion of the United States, especially the
lower portion of the Mississippi Valley.

[Illustration: FIG. 103.--_Bacillus anthracis_.]

_The symptoms vary in different cases_, depending on the organs affected,
and the virulence and amount of virus introduced. The _apoplectic form_ is
very acute. The disease sets in suddenly; the animal trembles, staggers,
falls and dies in a convulsion. Blood may be discharged from the nose and
with the urine and faeces.

In the _abdominal form_, abdominal pain, diarrhoea, prolapse of the rectum,
bloating and doughy swellings in the region of the abdomen occur.

In the _thoracic form_, the symptoms are bloody discharge from the
nostrils, salivation, rapid, difficult breathing and swelling in the region
of the throat. Local or skin lesions may occur in conjunction with, or
independent of, the above forms of disease. These are carbuncles one or two
inches in diameter that are hot and tender at first, but later become
gangrenous, diffused swellings.

On post-mortem examination the blood is found tarry and dark, and bloody
exudates may be found in the abdominal and thoracic cavities. The spleen is
soft and two or three times larger than normal. The diagnosis should be
confirmed by finding the _B. anthracis_ in the blood and tissues. The
death-rate is very high, usually about seventy-five per cent.

_The treatment is preventive._ Animals should be kept away from lots and
pastures where deaths from anthrax have been known to occur, unless
immunized against the disease. Marshy, swampy land that is infected with
the germs of anthrax should be drained and cultivated.

When an outbreak of the disease occurs, all of the animals should be
vaccinated. The carcasses of the animals that die should be cremated at or
near the place where they die. If hauled or dragged, the necessary
precautions should be taken against scattering the infectious material from
the carcass, and plenty of disinfectants used. Persons attending the
animals should be warned against opening or handling the carcass without
protecting the hands with rubber gloves.

_Anthrax vaccine_ should not be used by incompetent persons.

ULCERATIVE STOMATITIS. (ULCERATIVE SORE MOUTH.)--This is an infectious
disease of young animals. Pigs from a few days to a few weeks of age are
the most commonly affected.

_The specific cause_ of ulcerative sore mouths is the _Bacillus
necrophorus_ (Fig. 104). The infectious agent is distributed by the udder
of the mother becoming soiled with filth from the stable floor and yards,
and by affected pigs nursing mothers of healthy litters. Filth, sharp teeth
and irritation to the gums from the eruption of the teeth are important
predisposing factors.

_The symptoms_ are, at first, an inflammation of the mucous membrane lining
the lips and cheeks and covering the gums. The inflamed parts are first
swollen and a deep red color; later, white patches form and the part
sloughs, leaving a deep ulcer. As ulceration progresses, difficulty in
nursing increases until finally the young animal is unable to suckle. If
ulceration of the mouth is extensive, the animal may be feverish, dull and
lose flesh rapidly. Portions of the lips, gums and snout may slough off.
The death-rate in pigs is very high.

[Illustration: FIG. 104.--_Bacillus necrophorus_.]

_The preventive treatment_ consists in keeping the quarters and yards in a
sanitary condition, and using all possible precautions against the
introduction of the disease into the herd. The diseased young and mother
should be separated from the herd and the quarters disinfected daily. The
mouths of all the young should be examined daily and the diseased animals
treated. The ulcers should be scraped or curetted and cauterized with lunar
caustic, and the mouth washed daily with a two per cent water solution of a
cresol disinfectant. Dipping pigs headforemost into a water solution of
permanganate of potassium (one-half teaspoonful dissolved in a gallon of
water), twice daily, may be practised if the herd is large.

It is usually most economical to kill the badly diseased animals, as they
usually die or become badly stunted.

RABIES, HYDROPHOBIA.--Rabies is an infectious disease affecting the nervous
system, that is transmitted by the bite of a rabid animal and the
inoculation of the wound with the virus present in the saliva. It is
commonly considered a disease of dogs, but because of the disposition of
rabid dogs to bite other animals, rabies is common in domestic animals and
man.

Rabies is widely distributed, being most prevalent in the temperate zone,
and where the population is most dense. It has been excluded from
Australia, Tasmania and New Zealand by a rigid inspection and quarantine of
all imported dogs.

_The specific cause of rabies_ is probably a protozoan parasite (the Negri
bodies present in nerve-cells, Fig. 105). The germ spreads from the wounds
through the nerves and central nervous system. The disease-producing
organisms are present in great numbers in the nerve-tissue and saliva.

_The period of incubation_ varies from a few days to several months. It is
usually from ten to seventy days.

_The symptoms_ differ in the different species. There are two forms of the
disease: the _furious_ and the _dumb_. The former is more common.

[Illustration: FIG. 105.--Negri bodies in nerve-tissue.]

_In the dog, the symptoms may be divided into three stages_. The first, or
_melancholy stage_, usually lasts from twelve to forty-eight hours. The
animal's behavior is altered and it becomes sullen, irritable and nervous.
Sometimes it is friendly and inclined to lick the hand of its master. An
inclination to gnaw or swallow indigestible objects is sometimes noted.
Frequently a certain part of the skin is rubbed or licked.

The second, or _furious stage_, may last several days. Violent nervous or
rabid symptoms are manifested, and the dog may leave home and travel long
distances. The animal usually shows a strong inclination to bite. It may
move about snapping at imaginary objects in its delirium, and may bite any
person or animal with which it comes in contact. The bark is peculiar, the
appetite is lost and the animal becomes weak and emaciated.

In the third, or _paralytic stage_, the dog may present an emaciated,
dirty, ragged appearance. The lower jaw may drop, the tongue hangs from the
lips and the eyes appear sunken and glassy. Paralysis of the hind parts may
be present.

_In the dumb form_, the paralytic symptoms predominate and the disease
pursues a short course. Rabies terminates in death in from four to ten
days.

_Furious rabies_ is more common in the _horse_. The animal is very nervous,
restless and alert. It may attack other animals in a vicious manner,
kicking and biting them. The animal does not seem to care to eat or drink,
and usually shows violent nervous symptoms, such as biting the manger,
rearing and kicking when confined in the stable.

_Cattle_ butt with the horns and show a tendency to lick other animals.
They bellow more than common and the sexual desire is increased. Paralytic
symptoms are manifested early in the disease, and the animal may fall when
moving about. They soon present a gaunt, emaciated appearance.

In dogs the diagnosis is confirmed by a _microscopical examination_ of the
vagus ganglia and that portion of the brain known as Amnion's horn, and the
finding of Negri bodies in the nerve-cells. In case a person is bitten by a
dog, the animal should be confined until the disease is well advanced and
killed or allowed to die. The head should then be removed and forwarded to
the State laboratory, or wherever such examinations are made.

_The treatment_ is preventive. Wherever an outbreak of rabies occurs all
dogs should be confined on the owner's premises or muzzled. All dogs
running at large without muzzles should be promptly killed. A heavy tax on
dogs, and the killing of all dogs not wearing a license tag, would prevent
the heavy financial loss resulting from rabies, and the ravages of
wandering dogs in the United States. In countries where the muzzling of
dogs is enforced during the entire year, rabies is a rare disease.

FOOT-AND-MOUTH DISEASE.--This is a highly contagious and infectious disease
of cattle, sheep, goats and swine. It is characterized by the eruption of
vesicles on the mucous membrane lining the mouth, the lips, between and
above the claws and in the region of the udder and perineum. Man may
contract the disease by caring for sick animals; or by drinking raw milk
from a sick cow. Babies are most susceptible to infection from milk.

Foot-and-mouth disease was introduced into eastern Europe from the steppes
of Prussia and Asia near the end of the eighteenth century. It was
introduced into England about 1839, and in 1870 into Canada through the
importation of cattle from England. From Canada the disease spread to the
United States. Very few animals were infected during the 1870 outbreak, and
the disease was quickly stamped out in both countries.

Europe has been unable to eradicate foot-and-mouth disease. The different
outbreaks that occur from time to time cause enormous financial loss. In
the United States outbreaks of the disease have occurred in the following
years: 1870, 1884, 1902-'03, 1908 and 1914-'15. In the first two outbreaks
very few cattle contracted the disease, and the infection was quickly
stamped out. The third and fourth outbreaks were more extensive, and it was
necessary to slaughter several thousand cattle and hogs in order to
eradicate the disease. The first four outbreaks occurred in the eastern
States, and the disease was prevented from spreading to the principal
live-stock centers of the country, and the leading stock-raising States by
slaughtering the diseased and exposed animals and by county and State
quarantines. Early in the 1914-'15 outbreak, the disease spread to the
Chicago Stock Yards, and from there, through shipments of cattle, to the
principal live-stock sections of the country. The financial loss resulting
from this outbreak has amounted to several million dollars. The Federal and
State authorities have always been successful in stamping out the disease
in the United States.

_The specific cause_ of foot-and-mouth disease is a filterable virus that
is present in the serum from the vesicles, the saliva, milk, and various
body secretions and excretions from the sick animal. In the early stage of
the disease it is present in the blood. None of the many investigators have
been able to discover the microorganism that produces the disease.

Two of the outbreaks of foot-and-mouth disease in the United States
originated from an infected vaccine used for the inoculation of vaccine
heifers. The origin of the 1914-'15 outbreak has not been discovered. When
introduced into a country, the disease spreads rapidly, through the
movement of live-stock affected by the disease. Animals recently recovered
may infect other animals. Dogs, birds, people, vehicles, milk, roughage,
grains and other material from an infected farm may spread the disease.

_The period of incubation is short_. Symptoms of disease may be manifested
in from one to six days following exposure.

[Illustration: FIG. 106.--A cow affected with foot-and-mouth disease. Note
the accumulation of saliva about the lips. (From report of the Bureau of
Animal Industry.)]

_The first symptoms_ are fever, dulness, trembling and loss of appetite.
This is followed by vesicles or blisters forming on the mucous membrane of
the mouth, lips, between and above the claws and the region of the udder.
The inflammation of the mouth and feet may be very painful. Long strings of
saliva may dribble from the mouth and collect about the lips (Fig. 106). A
smacking or "clucking" sound is produced when the animal moves its jaws and
lips. The severe pain resulting from the inflammation of the mouth and
feet, and the difficulty in moving about and eating and drinking, cause the
animal to lose flesh and become emaciated. Milk cows may go dry.

_The death-rate is not heavy_. Some writers place it as low as two or three
per cent. Because of the erosions and sloughing of the tissues of the
mouth, feet and udder it becomes necessary to kill many of the animals.
Young animals frequently die of inflammation of the digestive tract. The
immunity conferred by an attack of the disease is not permanent.

[Illustration: FIG. 107.--Slaughtering a herd of cattle affected with
foot-and-mouth disease. (Photographed by S. J. Craig, County Agricultural
Agent, Crown Point, Indiana.)]

The most economical measures of _prevention and control_ are to buy and
slaughter all diseased and exposed animals, bury the carcasses in
quicklime, disinfect the premises (Figs. 107, 108 and 109) and enforce a
district, county and State quarantine, until after the infection has died
out. This statement may not hold true of methods of control in countries
where foot-and-mouth disease is widely distributed.

TETANUS. LOCKJAW.--This is an acute infectious disease that is
characterized by spasmodic contractions of voluntary muscles. The specific
germ remains at the point of infection, and produces toxins that cause
tetanic contractions of the muscles. It commonly affects horses, mules,
cattle, sheep and swine. The disease is most common in warm, temperate
climates.

[Illustration: FIG. 108.--Disinfecting boots and coats before leaving a
farm where cattle have been inspected for foot-and-mouth disease.
(Photographed by S. J. Craig, County Agricultural Agent, Crown Point,
Indiana.)]

[Illustration: FIG. 109.--Cleaning up and disinfecting premises where an
outbreak of foot-and-mouth disease has occurred.]

The _specific cause_ is a pin-shaped germ, the _Bacillus tetani_ (Fig.
110), that is present in the soil, especially those that are rich and well
manured. The germ enters the body by way of a wound, especially punctured
wounds. Infection may take place through some wound in the mucous membrane
lining the mouth, or other parts of the digestive tract. Infection may
follow a surgical operation, such as castration. In any case, the germ
requires an absence of air (oxygen) for its development.

_The period of incubation_ varies from one to two weeks, the length of time
depending on the nearness of the wound to a large nerve trunk or brain.

[Illustration: FIG. 110.--_Bacillus tetani_.]

The first _symptom_ observed is a stiffness of the muscles, especially
those nearest the point of inoculation or wound. The muscles of the head,
neck, back and loins are often affected first, and when pressed upon with
the fingers feel hard and rigid. The disease rapidly extends, producing
spasms of other muscles of the body. In breathing, the ribs show less
movement than normal, the head is held in one position and higher than
usual, the ears are stiff or pricked, the nostrils dilated, the lips rigid
or drawn back and the eyes retracted, causing the "third eyelid" to
protrude over a portion of the eye (Fig. 111). In most cases the muscles of
mastication and swallowing are affected. The animal may be unable to open
its mouth and swallows with difficulty. When standing, the limbs are spread
out so as to increase the base of support, and in acute cases about to
terminate fatally, the pulse is quick and small and the respiration
shallow, rapid and labored. The animal sweats profusely, falls down and
struggles violently, but remains conscious to the end.

[Illustration: FIG. 111.--Head of horse affected with tetanus, showing
"third eyelid" protruding over the eye.]

In the _subacute form_ (Fig. 112) the symptoms are mild, and the animal may
be able to move about, eat and drink without very great effort.

[Illustration: FIG. 112.--A subacute case of tetanus.]

_Treatment_ is largely preventive. All wounds should be carefully
disinfected. This is especially advisable in punctured wounds of the foot.
In communities, or on premises where tetanus is a common disease, animals
that have punctured or open wounds should be given a protective dose of
tetanus antitoxin.

_The curative treatment_ is largely good care. If a wound is present, it
should be thoroughly disinfected. The animal may be supported by placing it
in a sling. A comfortable box-stall, where the animal is not annoyed by
noises or worried by other animals, is to be preferred. A fresh pail of
water should be given the animal several times daily.

_The course_ of the disease varies. Death may occur within a few days, or
the disease may last two or three weeks. Animals that recover from tetanus
may show symptoms of the disease for several weeks. The death-rate is
highest in hot climates and during the summer months.

If the animal can eat, it is not advisable to feed a heavy ration of
roughage or grain. A very light diet of soft food, such as chops and
bran-mash, prevents constipation and encourages recovery. Drugs that have a
relaxing effect on the muscles may be given. Tetanus antitoxin may be given
in large doses.


QUESTIONS

1. What is septicaemia and pyaemia?

2. What is haemorrhagic septicaemia? Give methods of spreading and
   controlling this disease.

3. Give the cause of anthrax and symptoms.

4. What control measures are recommended in anthrax?

5. What is ulcerative sore mouth? Give the treatment.

6. Describe the symptoms occurring in rabies, and state the control
   measures recommended.

7. Name the species of animals affected by foot-and-mouth disease, and the
   countries where the disease is prevalent.

8. Give the methods of distribution and control of foot-and-mouth disease.

9. What is the specific cause and method of infection in tetanus? Give the
   treatment.



CHAPTER XXIX

INFECTIOUS DISEASES OF THE HORSE


STRANGLES. DISTEMPER.--This is an acute infectious disease associated with
a catarrhal condition of the air-passages and suppuration of the lymphatic
glands in the region of the throat. Colts are the most susceptible to the
disease. One attack renders the animal immune against a second attack of
the disease, but the immunity is not always permanent.

_The specific cause_, _Streptococcus equi_ (Fig. 113), was discovered by
Schutz in 1888. Strangles is commonly spread by exposing susceptible
animals to diseased animals, either by direct contact, or by exposing them
to the infection in the stable and allowing them to drink or eat food from
watering and feeding troughs on premises where the disease exists. The
predisposing causes are cold and sudden changes in the weather. For this
reason the disease is most prevalent during the late winter and early
spring.

[Illustration: FIG. 113.--Streptococcus of strangles.]

_The period of incubation varies_, usually from four to eight days.

_The symptoms_ at the beginning of the attack are a feverish condition and
partial loss of appetite. The visible mucous membranes are red and dry.
This is followed by watery nasal secretions that become heavy and purulent
within a few days. The inflammation may extend to the larynx and pharynx.

The glands in the region of the jaw become hot, swollen and painful, and
the animal may be unable to eat or drink. The swelling and inflammation of
the throat, and the heavy, pus-like secretions that accumulate in the nasal
cavities, cause difficult respirations. After a few days the abscesses
usually break, and the symptoms are less severe. If the abscesses break on
the inside of the throat, the discharge from the nostrils is increased.

The disease may be accompanied by an eruption of nodules, or vesicles on
the skin, or nasal mucous membrane.

In severe and chronic cases multiple abscesses may form. This complication
is indicated by emaciation and weakness. Such cases usually terminate in
death. Severe inflammation and swelling in the region of the throat may
terminate in strangulation and death. The death-rate is from one to three
per cent.

_The preventive treatment_ consists in using all possible precautions to
prevent the exposure of susceptible animals and practising the immunization
of exposed animals. The curative treatment is principally careful nursing.
Rest, a comfortable stall, nourishing feed and good care constitute the
necessary treatment for the average case of distemper. When the abscesses
become mature, they should be opened and washed with a disinfectant.
Steaming the animal several times daily relieves difficult breathing and
the irritated condition of the mucous membranes. In case the abscesses do
not form promptly and the throat is badly swollen, a blistering ointment or
liniment may be applied. Bitter and saline tonics, the same as recommended
in the treatment of indigestion, may be given with the feed.

INFLUENZA (CATARRHAL OR SHIPPING FEVER).--This is a well-known acute
infectious disease of solipeds. It is characterized by depression, high
body temperature and catarrhal inflammation of the respiratory and other
mucous membranes.

Several epidemics of influenza have occurred in the United States. The most
serious epidemic occurred in the latter part of the '70's, and the last one
in 1900-'01. Influenza is present in the principal horse centers in a
somewhat attenuated form.

_The specific cause_ of the disease has never been determined. The virus is
present in the expired air, nasal secretions and excreta. Close proximity
to a diseased animal is not necessary in order to contract the disease.
Stables may harbor the infection, and it may be distributed by such disease
carriers as blankets, harness, clothing of the attendant and dust.

_The predisposing causes_ are cold, exposure and changes in climate. When
the disease appears in a country, it is first present in the large cities,
and from there it is scattered to the outlying districts. The _period of
incubation_ is usually from four to seven days.

_The early symptoms_ of the disease are a high fever, marked depression and
partial or entire loss of appetite. The horse usually stands in the stall
with the head down and appears sleepy. The visible and respiratory mucous
membranes are inflamed, the respirations are quickened and the animal may
cough. The eyes are frequently affected, the lids and cornea showing more
or less inflammation. The digestive tract may be affected. At the
beginning, colicky pains may be present and later constipation and
diarrhoea. Symptoms of a serious nervous disturbance are sometimes
manifested.

The limbs usually become swollen or filled. This disappears as the animal
begins to improve. Pregnant mares may abort. The death-rate is low.

_The treatment required for the sick animals_ is largely rest, a light diet
and a comfortable, clean, well-ventilated stall, free from draughts.
Windows in the stall should be darkened. If the stable is cold, the body of
the animal should be covered with a blanket and the limbs bandaged. Two
ounces of alcohol and one drachm of quinine may be given three or four
times daily. Small doses of raw linseed oil may be given if necessary.

Horses that are exposed to cold, wet weather or worked after becoming sick,
frequently suffer from pneumonia, pericarditis, gastro-enteritis and other
diseases. Such complications should be given prompt treatment.

It is very advisable to give a protective serum to horses that are shipped
or transported long distances, and exposed to the disease in sale or
transfer stables.

GLANDERS, FARCY.--This is a contagious and infectious disease of solipeds
that is characterized by the formation of nodules and ulcers on the skin,
nasal mucous membrane and lungs.

Although glanders is one of the oldest of animal diseases, it was not until
1868 that its contagious character was demonstrated. The disease is widely
distributed. It became more prevalent in the United States after the Civil
War. The vigorous control measures practised by the State and Federal
health officers have greatly decreased the percentage of animals affected
with glanders. At the present time the disease is more often met with in
the large cities than in the agricultural sections of the country.

[Illustration: FIG. 114.--_Bacillus mallei_.]

_The specific cause of glanders is the Bacillus mallei_ (Fig. 114). This
microorganism was discovered in 1882. It is present in the discharges from
the nasal mucous membrane and the ulcers. These discharges may become
deposited upon the feed troughs, mangers, stalls, harness, buckets,
watering troughs, drinking fountains and attendants' hands and clothing.
Healthy horses living in the same stable with the glandered animals may
escape infection for months. It is usually the diseased animal's mate, or
the one standing in an adjoining stall, that is first affected. Catarrhal
diseases predispose animals to glanders, as the normal resistance of the
mucous membranes is thereby reduced. The most common routes by which the
germ enters the body are by way of the digestive and respiratory tracts. It
may enter the body through the uninjured mucous membranes of the
respiratory tract and genital organs, or through wounds of the skin.

_The period of incubation_ may be from a few to many days.

_The symptoms_ may be _acute_ or _chronic_ in nature. The _acute form_
pursues a rapid course. It is frequently seen in mules and asses, and it
may develop from the subacute or chronic form in horses. When the disease
is acute, the animal has a fever, is stupid, does not eat, and may have a
diarrhoea. In this form the lymphatic glands suppurate, the animal loses
flesh rapidly and dies in from one to two weeks.

[Illustration: FIG. 115.--Nasal septum showing nodules and ulcers.]

The _chronic form_ is the most common. It develops slowly and lasts for
years. The early symptoms of the disease (chilling and fever) usually
escape notice. The first visible symptom is a nasal discharge of a dirty
white color from one or both nostrils. This is usually scanty at first, and
intermittent, but later becomes quite abundant. The discharge is very
sticky, and adheres to the hair and skin. The most frequent seat of the
disease is in the respiratory organs, lymph glands and skin. Nodules and
ulcers appear on the nasal mucous membrane (Fig. 115), but they may be so
high up as to escape notice. The ulcers are very characteristic of the
disease. They are angry looking, with ragged, raised margins, and when they
heal leave a puckered scar. The submaxillary glands may be enlarged, and at
first more or less hard and painful, but later they become nodular and
adhere to the jaw or skin. Nodules and ulcers may form on the skin over the
inferior wall of the abdomen and the inside of the hind limbs and are known
as "farcy buds." Lymphatic vessels near these buds become swollen and hard.
The animal loses flesh rapidly, does not withstand hard work, and the limbs
usually swell.

It is sometimes difficult to diagnose the disease. The ulcers on the nasal
mucous membranes and elsewhere are very characteristic, and when present
enable the examiner to form a diagnosis. In cases of doubt, a
bacteriological examination of the nasal discharge may be made, or we may
resort to one or several of the various diagnostic tests. The Mallein test
is quite commonly used. The sterilized products of a culture of the _B.
mallei_ are injected beneath the skin of the suspected animal. This causes
a rise in body temperature and a hot, characteristic swelling at the point
of injection in glandered animals.

[Illustration: FIG. 116.--_Streptococcus pyogenes equi_.]

_Treatment is not recommended_ at the present time. Nearly all of the
States have laws which aim to stamp out the disease wherever found by
killing all affected animals, and thoroughly disinfecting the stables,
harness and everything which has been near the animal. Diseased animals
should be carefully isolated until slaughtered, and all animals exposed to
them should be subsequently tested for glanders.

CONTAGIOUS PLEUROPNEUMONIA (STABLE PNEUMONIA).--This is an infectious
disease of solipeds that usually results in a fatal inflammation of the
lungs and pleural membrane.

Many writers have described this disease as associated with influenza, but
it is frequently seen as a separate disease, usually involving only the
lungs and pleurae. It is prevalent in several parts of the United States,
more particularly the horse centers or large markets, where it appears in
the form of epidemics. In several of these localities it is known as
western or stable fever.

_The specific cause is not definitely known_. The _Streptococcus pyogenes
equi_ (Fig. 116) is very commonly present. This germ grows in the diseased
tissues. The disease is spread by direct or indirect contact, as when well
or susceptible animals are placed in the same stable with an animal
affected with the disease, or in stalls which have recently held diseased
animals.

_The period of incubation_ is from four to ten days following exposure.

_The symptoms_ are those commonly seen at the beginning of an attack of
simple pneumonia and pleurisy. They consist of chills, high fever, cough,
depression, difficult and labored breathing and loss of appetite. The
disease usually runs a course of from one to three weeks. The death-rate is
thirty per cent or more.

_The treatment_ is mainly preventive. Stables where horses having
pleuropneumonia have been kept should be cleaned and disinfected by
spraying the floors, stalls and walls with a four per cent water solution
of a cresol disinfectant. It is advisable to subject all newly-purchased
animals to a short quarantine period before allowing them to mix with the
other animals in the stable. Exposed animals may be given a protective
serum.

_The curative treatment_ is the same as recommended for the treatment of
simple pneumonia and pleurisy.


QUESTIONS

1. What is the specific cause of distemper? Give the symptoms and
   treatment.

2. What are the different methods of spreading influenza? Give the symptoms
   and treatment.

3. Give the cause and methods of controlling glanders.

4. Give the cause and treatment of contagious pleuropneumonia.



CHAPTER XXX

INFECTIOUS DISEASES OF CATTLE


[Illustration: FIG. 117.--A case of "lumpy jaw."]

ACTINOMYCOSIS, "LUMPY JAW."--This is an infectious disease that is
characterized by the formation of tumors and abscesses (Fig. 117), and the
destruction of the infected tissues. The disease is common in cattle and
usually affects the bones and soft parts of the head. In the United States,
where the disease is known as "lumpy jaw" the jawbone is commonly affected.
In European countries the disease frequently involves the tongue, and the
term "wooden tongue" is applied to it. The disease may affect regions of
the body other than the head. Actinomycosis of the lungs sometimes occurs.
Swine and horses may be affected by this disease.

_The specific cause_ of actinomycosis is commonly known as the ray fungus
(Fig. 118). This fungus grows on certain plants, and the animal usually
contracts the disease by eating plants or roughage that have the fungus on
them. Grasses having awns that are capable of wounding the mucous membrane
of the mouth and penetrating the gums are most apt to produce the disease.
Young cattle that are replacing and erupting their teeth are most prone to
"lumpy jaw." Conditions that favor bruising of the jaw and external wounds
favor the development of actinomycosis.

The fungus grows in the tissues, causing an inflammatory reaction and
destruction of the tissue. The ray fungus can be seen in the diseased
tissue or the pus as yellowish, spherical bodies about the size of a grain
of sand. Each of these bodies is formed by a large number of club-like
bodies arranged about a central mass of filaments.

[Illustration: FIG. 118.--The ray fungus.]

_The local symptoms_ are characteristic (Fig. 117). The tumor may involve
the soft tissues of the head. If the jawbone is affected the tumor feels
hard and cannot be moved about. Sometimes it is soft and filled with pus.
Tumors of long standing may possess uneven, nodular surfaces and fistulous
openings. When the tongue is affected, it is swollen and painful, and
prehension and mastication of the food may be impossible. When the pharynx
is the seat of disease, breathing and swallowing are difficult and painful.
Actinomycosis of the lungs may present the appearance of a chronic
pulmonary affection. If the disease involves the head and lungs, the animal
may become unthrifty and emaciated. In doubtful cases a microscopic
examination of a piece of the tumor, or some of the pus, may be necessary.

_The treatment is surgical and medicinal_. Small, external tumors may be
removed by an operation. Sometimes an incision is made into the diseased
tissue and a caustic preparation introduced.

The most desirable method of treatment is the administration of large doses
of iodide of potassium in a drench, or in the drinking water. The dose is
from one to three drachms daily for a period of seven to fourteen days. The
size of the dose depends on the size of the animal and its susceptibility
to iodism. An animal weighing 1000 pounds may be given two drachms. The
treatment is kept up until the symptoms of iodism develop. The condition is
indicated by a loss of appetite and a catarrhal discharge from the eyes and
nostrils. When this occurs, the treatment should be stopped, and the animal
drenched with one-half pound of Epsom salts, and the dose repeated after
three or four days. After an interval of two weeks, the iodide of potassium
treatment should be repeated if the growth of the tumor is not checked.

EMPHYSEMATOUS ANTHRAX, "BLACK LEG."--"Black leg" is an acute infectious
disease of cattle that is characterized by lameness and superficial
swellings in the region of the shoulder, quarter or neck. The swellings are
hot and painful and usually contain gas.

_The specific cause_ of "black leg" is a rod-shaped, spore-producing germ,
the bacillus of emphysematous anthrax (Fig. 119). This germ possesses great
vitality, and may live indefinitely in the soil. It has been known to live
for years in clay and undrained soils. Young animals that are in high
condition are predisposed to the disease.

The germ enters the body through abrasions in the skin and mucous membrane
of the mouth and intestines.

"Black leg" is a common disease of young cattle in all sections of the
country where cattle-raising is engaged in extensively. Outbreaks of the
disease are most prevalent in the early spring after the snow has melted,
and in the late summer in localities where cattle graze over the dried-up
ponds and swampy places in the pasture. The germs of black leg may be
carried from a farm where the disease is prevalent to non-infected premises
by surface water. The opening up of drainage ditches through stock-raising
communities may be followed by outbreaks of the disease.

[Illustration: FIG. 119.--Bacillus of emphysematous anthrax.]

_The symptoms_ of black leg develop quickly and may terminate fatally in a
few hours. These are general dulness, stiffness, prostration and loss of
appetite. Lameness is a prominent symptom. The animal may show a swelling
in the regions of the shoulder and hindquarters or on other parts of the
body. The swelling is very hot and painful at first, but if the animal
lives for a time, it becomes less tender, crackles when pressed on and the
skin may feel cold and leathery. Fever is a constant symptom. In the highly
acute form of the disease nervous symptoms, such as convulsions and coma,
occur.

_The tissue changes_ in the region of the swelling are characteristic. An
incision into the swelling shows a bloody, dark exudate and the surface of
the muscular tissue is dark. Frothy, bloody liquid escapes from the mouth,
nose and anus.

_The preventive treatment_ consists in thoroughly draining pastures and
yards where cattle run. This measure does not insure cattle against the
disease. Cattle that die of "black leg" should be cremated. This should be
done at the spot where the animal dies. If the carcass is moved or opened,
the ground should be thoroughly wet with a four per cent water solution of
a cresol disinfectant and covered with lime.

_Vaccination_ of the exposed or susceptible animals should be practised. On
farms where the disease exists it may be necessary to vaccinate the young
animals (less than two years of age) once or twice every year in order to
prevent the disease. Medicinal treatment is unsatisfactory.

TEXAS OR TICK FEVER.--Tick fever is an infectious disease of cattle. It is
caused by an animal organism that is present in the blood, and is conveyed
from the animal that is host for the tick fever parasite to the
non-infected animal by a tick (Figs. 120 and 121).

[Illustration: FIG. 120.--Cattle tick (male).]

[Illustration: FIG. 121.--Cattle tick (female).]

Tick fever was introduced into the southern portion of the United States
through importation of cattle by the Spaniards. Previous to the
establishing of a definite quarantine line between the permanently infected
and the non-infected sections, heavy losses among northern cattle resulted
through driving and shipping southern cattle through the northern States.
The specific cause and the part taken by the tick in its distribution were
not discovered until 1889-'90. Smith recognized and discovered the specific
cause of the disease, and Kilborn and Salmon proved by a series of
experiments that the cattle tick was responsible for the transmission of
the disease from animal to animal.

_The specific cause_ of tick fever is a protozoan parasite, _Piroplasma
bigeminum_ (Fig. 122). It is present in the blood of cattle that are
affected with this disease. The natural method of entrance into the body is
through the bite of the cattle tick. The disease may be transmitted by
inoculating blood containing the parasite into a susceptible animal.

There are two forms of the disease, the _acute_ and _chronic_.

_The symptoms of the acute form_ of the disease are a high fever,
depression, loss of appetite, diarrhoea, dark or bloody urine, staggering
gait and delirium. Death may occur within a few days from the time the
first symptoms are manifested.

_The symptoms of the chronic form_ of the disease resemble the acute form,
but are more mild. The animal is unthrifty and loses flesh rapidly. The
bloodless condition of the body is manifested by the pale, visible mucous
membrane. Death seldom occurs.

[Illustration: FIG. 122.--Blood-cells with _Piroplasma bigeminum_ in them.]

The most characteristic _diseased changes_ found on post-mortem examination
occur in the liver and spleen. The liver is enlarged, and a yellowish,
mahogany-brown color. The gallbladder is filled with a very thick bile. The
spleen may be several times the normal size and dark colored. When it is
cut into, the pulpy tissue may resemble thick, dark blood. The kidneys are
pale and the bladder may contain dark or reddish-colored urine.

In the northern States and outside of the quarantined area, the direct or
indirect exposure of the affected cattle to southern cattle, and the
presence of the cattle tick, _Margarophus annulatus_, are sufficient
evidence to confirm the diagnosis of this disease.

_The prevention and control_ depend on destruction of the cattle tick. In
the early history of the disease, shipping and driving of southern cattle
into and through the northern States caused outbreaks of tick fever and
heavy losses among northern cattle. This finally resulted in the locating
of the infected district, and the establishment of the Texas-fever
quarantine line in 1891 by Dr. D. E. Salmon.

Previous to this time Kilborne and Salmon proved that the cattle tick was
essential to the spread and production of the disease. A further study of
the life history of the tick resulted in the discovery that it could not
mature unless it became a parasite of horses, mules, or cattle. This has
led to the eradication of the tick in certain sections of the South, by not
allowing cattle access to a pasture or lot for a certain period, and by
freeing the animals from ticks by hand-picking, dipping and smearing.

The immunization of cattle that are shipped into an infected district for
breeding purposes is often practised. Immunity is obtained by introducing
the P. bigeminun into the blood, either by placing a few virulent young
ticks upon the animal, or by repeated inoculation with a very small
quantity of virulent blood.


QUESTIONS

1. Give the cause and treatment of actinomycosis.

2. Give the cause and treatment of emphysematous anthrax.

3. Give the cause of tick fever; distribution of the disease and methods of
   control.



CHAPTER XXXI

INFECTIOUS DISEASES OF POULTRY


FOWL CHOLERA.--This is a highly infectious disease of all species of
poultry, that is characterized by weakness, depression and yellowish
colored excrement.

The _specific cause_ of fowl cholera is the _Bacillus avisepticus_ (Fig.
123). This microorganism is transmitted to the healthy birds by the feed,
or water becoming contaminated with the discharges from the diseased birds.
According to Salmon, the period of incubating varies from four to twenty
days.

_The early symptoms_ are a falling off in appetite, high fever, dulness,
diarrhoea and weakness. The affected bird becomes drowsy, the head is drawn
toward the body, and it may remain asleep for long periods at a time.
Salmon states that the general outline of the sick bird becomes spherical
or ball-shaped.

[Illustration: FIG. 123.--_Bacillus avisepticus_.]

The disease is usually highly fatal. In the acute form the larger portion
of the flock may die off within a week. In the subacute and chronic forms,
the birds become greatly emaciated, and a few die off weekly through a
period of a month or longer.

_The tissue changes_ occurring in the disease are inflammation of all or a
few of the internal organs. Ward states that the most characteristic lesion
of fowl cholera is the severe inflammation of that portion of the small
intestine nearest to the gizzard. Small hemorrhagic spots may be found on
the heart and other organs.

_The treatment is both preventive and curative_. The preventive treatment
consists in quarantining newly purchased birds until we are satisfied that
they are free from disease. The occasional disinfection of the poultry
houses and runs is highly important. Cleaning the poultry house by removing
the floor, roosts, or any part of the house for the purpose of removing all
filth, and spraying the interior with a three per cent water solution of a
cresol disinfectant, should be practised. Lime should be scattered over the
runs, or the yards immediately about the house. The above preventive
measures form an important part of the care and management of the flock.
The carcasses of the dead birds should be burned. It is advisable to kill
all birds that are fatally sick.

All of the flock should be given antiseptics with the feed and water. Four
ounces of a water solution of copper sulfate, made by dissolving
one-quarter pound of this drug in one gallon of hot water, may be added to
each gallon of drinking water. Frequent disinfection of the drinking
fountains, feeding places and houses should be practised.

DISEASES RESEMBLING FOWL CHOLERA.--There are a few diseases, such as
septicaemia, limber neck and infectious enteritis, that are sometimes
mistaken for fowl cholera. These diseases are caused by different
microorganisms that may be found in the digestive tract and air-passages of
healthy birds, insanitary conditions and decomposed feed, especially meat.
It seems that under certain conditions, such as insanitary quarters and
birds that are low in constitutional vigor and weakened from other causes,
certain germs may become disease-producers. The death rate from mixed
infections is very heavy in poultry.

_The symptoms_ vary in the different cases. The disease may be highly
acute, as in limber neck, or chronic, extending over a period of a week or
more. Diarrhoea is not a prominent symptom in the majority of cases.

The post-mortem lesions vary from a hemorrhagic to a chronic inflammation
of the different body organs and serous membranes.

_The treatment_ is preventive. A frequent cleaning and disinfecting of the
poultry house and surroundings, avoiding the feeding of spoiled feed, or
allowing the drinking fountains and feeding places to become filthy, are
effective preventive measures. Sick birds should be either isolated and
quarantined, or destroyed. Antiseptics may be given with the feed and
drinking water.

AVIAN DIPHTHERIA (ROUP).--This infectious disease of poultry is especially
common in chickens. It is characterized by a catarrhal and diphtheritic
inflammation of the mucous membranes of the head.

_The specific cause of roup_ has not been determined. The disease-producing
germs are present in the discharges from the nostrils, eyes and mouth, and
the body excretions of sick birds. Birds having a mild form of roup, or
that have recently recovered from it, are common carriers of the disease.
The disease is usually introduced into the flock by allowing birds exposed
at poultry shows, or recently purchased breeding stock from an infected
flock, to mix with the healthy birds.

_The predisposing causes_ are very important factors in the development of
roup. Cold, damp, draughty, poorly ventilated poultry houses cause the
disease to spread rapidly and become highly acute.

_The symptoms_ differ in character in the different outbreaks of the
disease. Usually the first symptoms noticed are sneezing, dulness,
diminished appetite and a watery discharge from the nostrils and eyes.
Later the eyelids may become swollen and the nostrils plugged by the
discharge from the inflamed membranes. If the mouth is examined at this
time, an accumulation of mucus and patches of diphtheritic or false
membranes are found. In the acute form of roup the false membranes and
yellowish, cheesy-like material accumulate on the different mucous
membranes, and interfere with vision, breathing and digestion. The affected
bird becomes thin and weak. The death rate is very high in this form of the
disease.

_The preventive treatment_ consists in quarantining birds that have been
purchased from other flocks, and that have been exhibited, for a period of
three weeks. A careful examination of the mouth should be made. If a
catarrhal discharge from the nostrils and false membranes is present,
prompt treatment should be used. A sick bird should be held in quarantine
for several weeks after it has recovered, and receive a thorough washing in
a two per cent water solution of a cresol disinfectant before allowing it
to mix with the healthy birds.

The medicinal treatment consists in removing the discharges from the
nostrils and eyes with pledgets of absorbent cotton that are soaked with a
four per cent water solution of boric acid. Among the common treatments
mentioned are boric acid and calomel, equal parts by weight, blown into the
nostrils and eyes with a powder blower. Water solutions of boric acid,
potassium permanganate and hydrogen peroxide are recommended. Liquid
preparations are applied with pledgets of cotton, oil cans, or atomizers.

Many recoveries can be obtained with careful treatment. It is usually most
economical to kill the severely affected birds. Many poultrymen dispose of
the entire flock as soon as the disease makes its appearance, and clean and
disinfect the premises before restocking.

CHICKENPOX.--In some sections the disease appears in another form, known as
_chickenpox_ (contagious epithelioma), in which nodules form on the skin
along the base of the comb and other parts of the head, or both forms may
be met with in the same flock. The nodules should be treated with vaseline,
or glycerine ointments containing two per cent of any of the common
antiseptics or disinfectants.

ENTERO-HEPATITIS. "BLACKHEAD."--This is a very fatal disease of young
turkeys. Grown turkeys and other fowls are not so susceptible to the
disease. It is characterized by an inflammation of the liver and
intestines, especially the caeca.

_The specific cause_ is a protozoan microorganism, _Amoeba meleagridis_.
Adult fowls and turkeys may act as carriers of the germ, and the young
turkeys become infected at an early period.

_The symptoms_ are diminished or lost appetite, dulness, drooped wings,
diarrhoea, weakness and death. When the disease becomes well advanced, the
head and comb become dark.

_The course of the disease_ is from a few weeks to three months. Very few
of the young turkeys survive.

_The treatment_ is almost entirely preventive. The same precautionary
measures for the prevention of the introduction of disease into the flock,
recommended in other infectious diseases, should be practised. Turkeys that
survive should be disposed of. As chickens may harbor the disease-producing
germs, we should not attempt to raise turkeys in the same quarters with
them. Eggs should be obtained from disease-free flocks. Wiping the eggs
with a cloth wet with fifty per cent alcohol may be practised. The same
recommendations regarding the cleaning and disinfecting of the quarters
described in the treatment of fowl cholera should be practised.

If an outbreak of the disease occurs in the flock all of the sick birds
should be killed, and their carcasses cremated. Moving the flock to fresh
runs and the administration of intestinal antiseptics are the only
effective lines of treatment.

AVIAN TUBERCULOSIS.--Tuberculosis of poultry is a serious disease in some
countries. Poultry usually contract tuberculosis by contact with a
tubercular bird, and not from other domestic animals and man.

_The symptoms_ are of a general character, such as emaciation, weakness,
wasting of muscles and lameness. Tubercular growths may appear on the
surface of the body.

If we suspect the presence of the disease, it is advisable to kill one of
the sick birds and make a careful examination. The finding of yellowish,
white, cheesy nodules or masses in the liver, spleen, intestines and
mesenteries is strong evidence of tuberculosis. A bacteriological
examination of the tissues may be necessary in order to confirm the
diagnosis.

The same _methods of treatment_ as recommended in tuberculosis of other
domestic animals may be used in eliminating the disease from the premises
and flock. This consists in killing and cremating all birds showing visible
symptoms, moving the apparently healthy portion of the flock to new
quarters and wiping the eggs with alcohol. The old quarters should be
cleaned, disinfected, and then allowed to stand empty for several months,
when we should again spray with a disinfectant, and scatter lime over the
runs. If the cleaning and disinfecting have been thorough, we may safely
turn young or healthy birds into the old quarters. All possible precautions
against carrying the infection to the healthy flock must be observed.


QUESTIONS

1. Give the cause and treatment for fowl cholera.

2. What diseases resemble fowl cholera? Give the treatment.

3. Give the symptoms and treatment for roup.

4. Give the treatment for "blackhead."

5. Give the treatment for Avian tuberculosis.



REFERENCE BOOKS

Pathology and Therapeutics of the Diseases of Domestic Animals, Vol. I-II,
Hutyra and Marek.

Veterinary Medicine, Vol. I-V, Law.

General Therapeutics for Veterinarians, Frohner.

Prevention and Treatment of the Diseases of Domestic Animals, Winslow.

Age of the Domestic Animals, Huidekoper.

Veterinary Materia Medica and Therapeutics, Winslow.

Veterinary Anatomy, Sisson.

Chauveau's Comparative Anatomy of Domestic Animals.

Manual of Veterinary Physiology, Smith.

Annual Reports of Bureau of Animal Industry, from 1902 to 1911.





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