SYMPTOMS OF TUBERCULOSIS IN CATTLE.
Microscope and staining; by centrifuge; by agglutination test; by inoculation; by tuberculin test; tuberculin; reaction; precautions, temperature before injection, exclusive of other illness, of parturition, abortion, heat, isolation, of hot building, of cold draughts, of hard floor, of faulty milking, privation of water, of change of food, of journey, of rude handling, of previous recent tests, of antipyretics, make special examination in unthrifty, test excluded animals later, danger of infecting through thermometer; technique; dose; time of injecting; identification and record of subjects; seat of injection; sterilization of syringe and skin; temperatures hourly or every second hour from 8th to 16th or later; typical reaction; accurate record of feeding, watering, milking or other occasion of hyperthermia or hypothermia; passing on the value of a rise; local swellings; chills; tremors; effect of test on general health of reacting and nonreacting animal; action on parturient cows; reliability of test. Relation of human to bovine bacillus; varying character of microbes generally, of tubercle bacillus in man; bacillus of man and bird interchangeable; tuberculosis in man and ox, similarity, coextensive, apparent exceptions, direct infection—man to cattle—cattle to man; encrease of tabes; experiments of Adami, Ravenel and Garnault; experiments on cold blooded animals; bearing of variations of susceptibility on sanitary work. Treatment: When admissible; hygiene; rich feeding; oleaginous seeds: cod liver oil; pneumatic cabinet; grooming; warm bath; medicated inhalations; sulphurous acid; chlorine; formaline; calmatives; carbonate of creosote; derivatives; streptococcic serum; air or oxygen in peritoneum; excision of tubercle; Prevention; Extinction in cattle; expense, supply of tuberculin and efficient veterinarians; appraisment; indemnities; vermin; disinfection; scheduling; control of purchases. Breeding healthy stock from infected; raising healthy offspring without sterilizing the milk. Removal of unthrifty and suspicious animals. Removal of animals showing objective symptoms, or, tuberculin reaction. Generally applicable measures. Hygiene of milk, butter, cheese, whey, oleomargarine. Hygiene of meat.
Tuberculosis may be acute or chronic, yet as seen in cattle, from casual infection, it usually comes on very slowly and insidiously and follows a chronic course. As the symptoms vary according to the organs involved it will be convenient to consider these in turn beginning with such as show the most diagnostic phenomena.
Pulmonary Tuberculosis. Though one of the most common and dangerous forms of the disease this may last for months or years without any suspicion on the part of the owner or caretaker of anything amiss. There may be an occasional cough, short, weak, dry, wheezing, perhaps repeated and roused by opening the stable door in cold weather, by leaving the stable for the cold outer air, by rising suddenly in the stall, by being driven on a run for a short distance, by drinking cold water or by eating dusty food. If driven for some distance, or put to draught work (ox) the subject blows more than the others. Sometimes even at rest, breathing is slightly accelerated. Yet the spirits may be as good, the eye as clear and full, the coat as smooth and sleek and the skin as soft and mellow as in health. Some such animals give as much milk, of as rich a quality, or, when put up to fatten, lay on flesh apparently as well as their healthy fellows. In favorable cases percussion may elicit circumscribed areas of dulness, and wincing or other sign of tenderness, and auscultation may detect crepitation or wheezing over the same points. By covering the nose and mouth with a sac or blanket the breathing is rendered more labored and the morbid sounds become clearer and more definite. The use of a stethoscope or phonendoscope may also render them more distinct. The morbid râles are more significant of tuberculosis if found in a number of isolated and circumscribed spots, with healthy respiratory murmur between, than if simply surrounding a single extended area of flatness as is usual in pneumonia. Much, however, stands in the way of success at this early stage. The heavy muscular and bony mass of the shoulder covers the anterior lobe and partially muffles the auscultation sound, while it renders percussion useless. The thick covering of the ribs in fat animals proves a serious barrier to successful auscultation and percussion. The varying plenitude of the abdominal viscera, and the rumbling, trickling, gurgling, and in the case of the rumen the crepitation of the contents, tend to complicate, obscure or cover up the pulmonary sounds. There is usually no appreciable elevation of temperature, or a slight rise of about one degree takes place at distant and uncertain intervals so as to render it useless for purposes of diagnosis.
When the disease is more advanced and the pulmonary lesions more extensive, the animals usually appear less thrifty on the same feeding, yet fat animals are habitually killed for food that show quite extensive pulmonary tuberculosis. With loss of condition, the coat loses its lustre somewhat, the hair becomes dry and stares in patches, and the skin loses its mobility and mellowness. The cough may be more frequent, perhaps paroxysmal under excitement, harsher, more short and broken, and either dry and husky or moist and gurgling, with a succeeding deep inspiration perhaps a moist râle. When the skin on the last ribs is pinched up between the fingers and thumb it is slower in flattening down to its normal smoothness, pinching of the spine at the shoulder or back, or it may be of the sternum, may cause wincing and even moaning, and the same may come of percussing the ribs smartly with the closed fist. There is now more decided evidence of flatness on percussion on the various affected points, and of abolition or lessening of the respiratory murmur, which is replaced by wheezing, or by bronchial blowing sound, heart beats and abdominal crepitation or gurgling, conveyed to the ear more clearly through the intervening consolidated tissue. The breathing may be slightly accelerated even at rest, and becomes distinctly so on exertion. The appetite fails somewhat and the secretion of milk lessens, or it may become more pale and watery. Chronic tympany occurring after meals occasionally appears, usually indicating tuberculosis of the glands along the œsophagus with pressure on that organ impairing eructation, and on the vagus nerve so as to impair nervous control. In connection with this there come on signs of generalization of the tubercle, as irregularity of the bowels, or enlargement or nodular induration of some of the superficial lymph glands, as the pharyngeal, prescapular, prepectoral, axillary, prefemoral, inguinal or mammary. Expectoration is usually abundant but it is difficult to secure it for diagnostic purposes since the moment it reaches the pharynx it is instantly swallowed, while any that may have been projected into the anterior nares is licked out by the pointed tongue. Nocard tried to secure this through a cannula passed in between the tracheal rings but with very little success. Others have introduced the hand into the pharynx, rousing the cough by tickling the larynx, and attempting to bring out the expectoration in the hand. When it can be secured its solid and opaque flocculi may be stained and examined for the bacillus, or it may be inoculated on a Guinea pig, intraperitoneally, to test its virulence. If there are open vomicæ or complex infection the breath is usually heavy and mawkish.
In the most advanced stages the symptoms are very characteristic. The subject is miserably thin and wastes visibly from day to day, the hair is dry and erect, most marked along the spine, the skin is scurfy, rigid, lousy, and clings firmly to the bones, the eyes are pale, deeply sunken in their sockets and bleary, the tears running over the cheeks, while a yellowish, granular, fœtid, and often gritty discharge flows from the nose, and dries in masses around the alæ. The cough is weak, painful, paroxysmal, and easily roused by pinching the back or breast or percussing the ribs. The breathing is liable to be hurried, even panting, and the animal may stand most of its time with nose extended to obviate the oppression that comes of recumbency. All the visible mucosæ are pale and blanched, and the pulse weak and rapid with every indication of anæmia. The temperature is usually raised to 104° or 105° F. and the milk secretion is completely arrested. Indications of generalized tuberculosis become more marked in the enlarged glands, diarrhœa, and clouded (purulent), or blood stained urine with microscopic casts, and even anasarca. The morbid sounds in the lungs have become a complex variety according to the nature of the lesion, blowing, wheezing, amphoric, friction, creaking, mucous, with the other bruits conveyed from adjacent organs. Death usually occurs in a state of complete marasmus, after months or years of illness.
Tuberculosis of the Abdomen. This usually affects the intestines, mesenteric glands, peritoneum, liver, spleen and pancreas, and has been known as tabes mesenterica. The generative organs also occasionally suffer, in which case, an early and rather persistent symptom is sterility, with a too frequent or it may be persistent desire for the bull (nymphomania). There is usually a steady loss of condition in spite of good feeding, the impaired functions of the intestinal mucosa, but especially of the mesenteric glands, liver and pancreas, interfering seriously with absorption and assimilation. The victims are therefore known as piners. While there may be more or less fever, highest in the evening, this is by no means marked, and cough and respiratory trouble may be entirely absent. Indications are not lacking, however, of digestive trouble. Slight tympany may follow meals, and the bowels are irregular, costiveness alternating with diarrhœa. If heavy feeding is resorted to, diarrhœa is the usual result, accompanied, it may be, by colic and tympany. There is a tendency to formation of pea or nut-like nodes under the skin of the flank, and Kleinpaul claims that the tubercles or vegetations on the rumen can be felt by manipulation of the left flank. Clearer evidence can often be had by rectal exploration, the tubercles and enlarged glands being felt on the rumen, in the knotted mesentery and in the sublumbar and subsacral region.
In case of uterine tuberculosis, the nymphomania may be supplemented by a purulent discharge, and rectal exploration may detect the tubercles on its surface, in the broad ligaments or even in the enlarged ovaries.
Great fœtor of the fæces may indicate ulceration of the mucosa, indigestion or impaired hepatic function.
For a great length of time the disease may be virtually confined to the mesenteric or portal glands, or even to the spleen, while the animal enjoys fairly good health. Again, in some instances, the subject may be fat and sleek, though the rumen, omentum or mesentery is to a large extent literally covered with tuberculous vegetations. The tuberculization of the intestines, mesenteric glands, liver or pancreas interferes far more with the general health than does even extensive peritoneal tuberculosis.