Page:EB1911 - Volume 28.djvu/25

Rh non-tuberculous animals it has no appreciable action. Medical treatment is of little if any avail. Preventive measures are of the utmost importance. Animals proved free of tuberculous taint should alone be bred from, and those found diseased should be at once completely segregated or slaughtered. Before being used as food the flesh should be well cooked, and the milk from tuberculous cows should be boiled or heated to a temperature of 155° F.

Black-quarter, or black-leg, is a specific, inoculable disease which occurs in young stock from a few months to two years old, in

various parts of the country, and generally in low-lying damp situations. It was classed with anthrax until 1879, when its nature was investigated by Arloing, Cornevin and Thomas, who termed it symptomatic anthrax (Charbon symptomatigue)—a misleading name for a disease which is perfectly distinct from anthrax. This disease is caused by the Bacillus Chaauvaei, and natural infection takes place through small wounds of the legs and feet or other parts. At first it is a local disease affecting usually a hind quarter, though sometimes the characteristic swelling forms on the shoulder, neck, breast, loins or flank. The chief symptoms are sudden loss of appetite, accelerated pulse and respiration, high temperature, debility, lameness or stiffness, followed by the formation of a small, painful swelling which rapidly increases in extent, becomes emphysematous, and in the centre cold and painless. Incision of the tumour gives escape to a red, frothy, sour-smelling fluid. This disease runs its course very rapidly and nearly always terminates fatally, even when medical treatment is promptly applied. Infection can be prevented by resorting to protective inoculation by one of the methods introduced by Arloing, Kitt and others. The natural virus-muscle from the lesion, dried, reduced to powder and attenuated by heat at a high temperature, and a pure culture of the causal organism, are employed as vaccines. The vaccine is introduced subcutaneously at the tip of the tail or behind, the shoulder. Immunity lasts for about twelve months.

Abortion, or the expulsion of the foetus before viability, is a contagious disease in cows. In a herd a case of abortion or

premature birth from accident or injury sometimes occurs, but when a number of pregnant females abort the cause is due to specific infection of the womb. The microbe of abortion induces catarrh of the uterus and the discharge contains the infective agent. The virus may be transmitted by the bull, by litter, attendants, utensils, or anything which has been contaminated by the discharge from an infected cow. Whenever abortion occurs in a shed the cow should be at once isolated from the others, if they are pregnant, and cleansing and disinfection immediately resorted to, or preferably the pregnant cows should be quickly removed out of the shed and every care should be taken to keep them away from the affected cow and its discharges; the litter and the aborted foetus being burned or otherwise completely destroyed, and the cowshed thoroughly disinfected with quicklime. To prevent further infection, the hinder parts of the in-calf cows should be washed and disinfected from time to time.

Contagious mammitis is a common disease in milch cows. It has been investigated by Nocard and Mollereau, and proved

to be caused by a streptococcus which is transmitted from one cow to another by the hands of the milkers. The microbe gains access to the quarter by the teat and induces catarrhal inflammation of the milk ducts and sinuses, with induration of the gland tissue. This disease develops slowly, and except in cases complicated by suppuration, there is little or no constitutional disturbance, though sometimes the affected cows lose condition. The nilk at first preserves its normal appearance, but is less in quantity; it curdles quickly, is acid, and when mixed with good milk produces clotting; then it becomes thin and watery, and finally viscous, yellowish and foetid. At the base of the teat of the affected quarter induration begins and gradually extends upwards, and if not checked the disease passes from one quarter to another until the whole udder is attacked. Prevention can be secured by washing and disinfecting the udder and teats and the milkers' hands before and after milking. Diseased cows should be isolated, their milk destroyed or boiled and fed to pigs, and after each milking the teats should be injected with a warm solution of boracic acid or sodium fluoride. Infected cowsheds should be thoroughly cleansed and disinfected.

Parturient paralysis, or mammary toxaemia, also known as milk fever, though neither a febrile nor a contagious malady, was until

quite recently a very fatal affection of dairy cows. It is caused by a nerve poison which is formed in the udder soon after parturition; and, according to Schmidt, the toxin enters the circulation and affects especially, the central nervous system and the muscles, and in a less degree all the organs of the body. This disease usually attacks good milking cows within a few days of an easy labour and seldom before the third or fourth parturition. In twenty-four to forty-eight hours after calving the cow becomes excited and restless, strikes at the abdomen with the hind feet, whisks the tail, lows, grinds the teeth, staggers, falls, makes ineffectual attempts to rise, and eventually lies comatose, stretched on her side with the head extended or inclined towards the shoulder. The eyes are dull, injected and insensitive; general

sensation, voluntary motion and the power of swallowing are lost. Secretion of milk fails, digestion is suspended, fermentation of the contents of the paunch sets in, with tympany, constipation and retention of urine. The pulse becomes feeble or imperceptible. Respiration is slow, sometimes stertorous or groaning, and the temperature is low or subnormal. If not treated the animal dies in two or three days from prolonged coma or heart failure.

The curative treatment of this disease continued very unsatisfactory until 1897, when Schmidt, a veterinarian of Kolding, Denmark, introduced the method of injecting the teats with a solution of potassium iodide in conjunction with insufflation of atmospheric air. The immediate results of this line of treatment were astonishing. Rapid recovery became the rule, and in most cases the comatose condition disappeared in less than six hours, and the average mortality (40 to 60%) was reduced to 6%. Afterwards chinosol and other antiseptics were substituted for the potassium salt, and later pure oxygen or atmospheric air alone was injected into the udder, with the result of increasing the recoveries to 99%.

Cowpox is a contagious disease of much less frequent occurrence now than formerly, probably owing to improved hygienic management.

In many localities the disease appears in all heifers which have recently calved on certain farms. There is usually a slight premonitory fever, which is generally overlooked; this is succeeded by some diminution in the quantity of the milk, with some increased coagulability, and by the appearance of the eruption or “pox” on the udder and teats. In well-observed cases the udder is hot and tender on manipulation for a day or two previous to the development of small pale-red nodules about the size of peas; these increase in dimensions to from three-fourths to one inch in diameter by the eighth or tenth day, when their contents have become fluid and they present a depressed centre. This fluid, at first clear and limpid, becomes yellowish white as it changes to pus, and soon dries up, leaving a hard, button-shaped black crust, which gradually becomes detached. On the teats, owing to the handling of the milker or to the cow lying on the hard ground or on straw, the vesicles are early ruptured and sores are formed, which often prove troublesome and may cause inflammation of the udder.

Actinomycosis, though affecting man, horses, pigs and other creatures, is far more common in the bovine species. The fungus

(Actinomyces) may be found in characteristic nodules in various parts of the body, but it usually invades the bones of the jaws, upper and lower, or the soft parts in the neighbourhood of these, as the tongue, cheeks, face, throat and glands in its vicinity. About the head the disease appears to commence with slight sores on the gums or mucous membrane of the mouth or with ulcers alongside decaying teeth, and these extend slowly into the tissues. If the jaw is affected, a large rounded tumour grows from it, the dense outer bone becoming absorbed before the increasing soft growth within. Soon the whole becomes ulcerated and purulent discharges take place, in which are found the minute, hard, yellow granules which contain the fungus. When the tongue is affected, it becomes enlarged and rigid; hence the designation of “wooden tongue” given to it by the Germans. In the course of time the surface of the organ becomes ulcerated, and yellowish masses or nodules may be seen on the surface. Sometimes the entire face is involved, the lips and nostrils becoming swollen, hard and immovable, often rendering respiration difficult. Around the throat there are rounded dense swellings, implicating the glands. When the disease is well-defined and of slight extent, the parts involved may be removed by the knife, wholly or partially. If the latter only, then the remaining affected tissues should be dressed with tincture of iodine or iodized carbolic acid. Chromic acid has also been found useful. A course of potassium iodide internally is sometimes curative and always beneficial.

The contagious diseases of the sheep (other than those of foot-and-mouth disease, anthrax, rinderpest, black-quarter) are comparatively few.

The formidable disorder of sheep-pox is confined chiefly to the continent of Europe. It is extremely contagious and fatal, and in these

and some other characteristics resembles human smallpox. From three to twelve days after being exposed to infection the sheep appears dull and listless, and eats little, if anything; the temperature rises; there are frequent tremblings; tears flow from the eyes; and there is a nasal discharge. Red patches appear inside the limbs and under the abdomen; and on them, as well as on other parts where the skin is thin, dark red spots show themselves, which soon become papules, with a deep hard base. These are generally conical, and the apex quickly becomes white from the formation of pus. This eruption is characteristic and unmistakable; and the vesicles or pustules may remain isolated (discrete pox) or coalesce into large patches (confluent pox). The latter form of the disease is serious. In bad cases the eruption may develop on the eyes and in the respiratory and digestive passages. The course of the disease lasts about three weeks or a month, and the eruption passes through the same