NORTHLAND FARMER

Northern Advocate, 9 July 1938, Page 13

NORTHLAND FARMER

Infectious Abortion. Infectious abortion is very frequent cattle of all countries; it ranks second among Infectious diseases in cattle; first among the infectious diseases is still tuberculosis. The germs arc transmitted by sick or infected cows or pregnant heifers. They may be m the uterus or the udder, in discharges from the generative organs at time of aborting and for a considerable pcr•°d afterwards, in certain lymph gland;; and joints, in the intestines of newlyborn calves, and in the generative organs of bulls. The disease has been produced experimentally in pregnant heirers through feeding them food soiled with discharges from cows which had recently aborted. Healthy bulls are capable of transferring the germs from affected to healthy cows. The milk of sick cows contains many Brucella-germs, and even may trans-

mit them to the human consumer. Sterility is a frequent factor in herds which are affected' with the disease. Even bulls which have proved very fertile may be infected with Brucellagerms and lose their value as a sire. Infection is transmitted from cow to cow by' food contaminated with any excretion of an infected animal. Man. may possibly become infected by eating butter, milk, or cheese from infected animals or by handling infected material. Cows are known to excrete the organisms in their milk for as long as seven years. Many cases of Brucella infections are similar to cases ot gripe, the patients complain of fatigue and malaise, having a certain degree of temperature and fever. In other casts stomach and intestines are infected. The mortality is, as a rule, very low. The incubation period' is frotai five days to six weeks in man, imioh longer sometimes in cattle. An exact diagnosis can be reached, states an'overseas authority, by quite a numbed of means; agglutinations test, blood cujftures, cultures from the urine and the discharge from the generative organs, furthermore inoculation of animals, and skin test for sensitivity to Brucella-germs. Frequently used is the agglutination test, which overseas has been found very accurate, though not absolutely infallible. In the United States about ten million official tests are. made annually. They are a valuable guide in freeing infected ■herds from the disease and preventing the herds from new infections. It is no rare thing that the disease is introduced into clean herds through the purchase of cows or heifers that carry the germs in their bodies. Excluding them fundamentally from a clean herd would usually mean the prevention from the disease. A report of a commission to study the disease in U.S.A. said that progress in the elimination of the disease has been much more rapid since official testing has been carried on. The scheme has been supported by indemnities for condemned animals.

When Will the Cow Calve?

While the phenomena attending the birth of the young of the cow are not identically the same in any two animals, yet there are certain well-denned symptoms that indicate the approaching event. These symptoms arc more or less constant, depending upon the individual and other conditions of which we know little. It is not definitely known just what causes birth to take place; whatever it is, it is quite variable, as in the cow it is not unusual for it to vary as much as 80 days. Near the time of the birth of the young, there are numbers of changes that take place in the cow tending toward facilitating the act of giving birth to the calf. The calf is expelled into the vagina largely by the muscular walls of the uterus, and then the expulsion is completed by the assistance of the abdominal walls and dia-

Edited By C. E. Cuming

phragm to the aid of the uterus. The force is exerted against the unborn calf through the forcing of the intestines and abdominal contents against the uterus and the posterior end of the calf. If ft were not for this latter fact it would no doubt be impossible for the cow to give birth to young. On the approach of calving, the udder of the cow usually shows some activity, and, in maiden heifers, this may take place several weeks before calving. At first there is almost a clean, watery fluid', which gradually assumes more the appearance of normal milk, until within a few days before calving, when it becomes yellow, thick and heavy, greatly resembling colostrum. While this is a fairly constant sign, it does not always hold, as heifers that are not with calf have been known to give large quantities of milk while other heifers would give little or no milk until about the time of calving. One sign that does not fail, however, is the sinking or dropping of the muscles of the croup; this makes a small depression on either side and just a little in front of the base of the tail. Another constant sign .is the enlargement or thickening of the walls of the vulva. The lips of the vulva stand apart more than usual and there generally appears more or less abundant discharge of thick mucous. As the time of calving draws near the cow becomes disturbed and' uneasy; she may move slowly and may withdraw from the rest of the herd. She eats slowly or not at all; she may lie down and get upon her feet at short intervals, and she may pay slightly and show evidence of slight, colicky pains. A good plan to follow with the cow when she has calved all right and is comfortable, is to cause as little interference as possible to the carrying out of her maternal instinct. The cow is a very much domesticated animal, but her natural instincts are still strong enough to guide her in the care of the calf.