COMMON DISEASES OF FARM ANIMALS
By R. A. Craig, D.V.M.
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.
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
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.
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).
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.
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.
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.
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.
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).
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.
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 100.5260 F. Cattle 101.4260 F. Sheep 104.0260 F. Swine 103.0260 F. Dog 101.4260 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.
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?
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.
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.
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.
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
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.
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.
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.
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).
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.
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.
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.
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.
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.