CONTAGIOUS ABORTION AND STERILITY.

Auckland Star, Volume LX, Issue 39, 15 February 1929, Page 17

CONTAGIOUS ABORTION AND STERILITY.

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Contagious abortion and tuberculosis are said, on good authority, to be the two diseases which cause * the biggest loss to the dairy farmer. Tuberculosis is probably responsible for a bigger aggregate loss than abortion, but it = is pretty certain that the latter is responsible for the higher individual losses. In cases of abortion the loss of the calf, loss of milk and increase of working costs, besides damage to the cow as a breeding animal, have all to be reckoned with. The cow herself is in most cases an uneconomic unit for the following year. The cause is due to a particular microbe or bacillus which swarms in the immature calf, in the membranes and discharges of the womb. The microbe is often present in the milk of an infested animal, and will live for several months outside the bodv.

The Bull Not to Blame. Formerly the bull was blamed as the source of infection, but it is now known that the disease-producing germ disooTered in 1896 by Bang, the Danish veterinary surgeon, is introduced into a herd by the purchase of new animals that are affected. Infection is (says a writer in the '"Livestock Journal," of England) nearly always contracted through the mouth. In-calf animals become affected by grazing, eating food, or drinking water that has been contaminated by an infected animal. Cows that have recently aborted will spread the disease by their discharges. It can be spread by the litter, and hands and boots of attendants, dogs, wild animals and calves that were aborted just before full time, carrying the germ of disease in the intestines. The only possible chance that there appears to be of the bull carrying infection is mechanically in the event of his serving a clean cow immediately after having served a diseased one. Recent experiment has shown, however, that it is difficult to infect a cow by means of the vaginal tract, and the bull appears to 1« sexually immune.

Germs in the Body. When the germs have once entered the body they locate themselves in the udder of cows not in-calf, but in the womb of pregnant ones, and it is only in the event of pregnancy that they produce disease. It is highly probable that early abortions are the result of the germs being already in the body, located at the udder, at the time of conception. Late abortions take place when the germs happen to be picked up during pregnancy. It may be picked up late during one pregnancy, and abortion does not take place until after the next conception. The presence of the disease makes no difference to the apparent health of the animal until abortion is about to take place, when about three days before the usual calving signs appear, and there is a discharge from the genital organs. In most cases, however, no signs are given, especially when abortion takes place during the early stages of pregnancy. When the calf is slipped entirely enclosed in the membrane during the first four months of pregnancy, there may be no sign either in health or otherwise of anything being wrong, until the cow comes in season again, and then it is thought simply that she failed to conceive at the previous bulling. There is pain and restlessness when abortion occurs during the later stages of pregnancy, and it is easier to discover what is wrong.

An infected animal usually becomes immune after the first abortion, but a few will abort more than once. The danger is the amount of infection spread to the rest of the herd when the disease microbe is present in one of the animals without the owner being aware Of it. Treatment. A cow that shows signs of abortion, that may be thought to look like aborting, or that may already have done so, should be immediately isolated, and every part of the building and implemente with which she has come into contact thoroughly disinfected by carbolic acid (6oz. to a gallon of water), copper sulphate (4oz. to a gallon of water), Jeyes, Izal, etc. Houses kept scrupulously clean and thoroughly disinfected is one of the greatest safeguards. Further treatment of an animal that has aborted consists of syringing out the womb twice daily with a mild disinfectant; an ordinary enema syringe will do. This. prevents the spread of infection. In case of any complications, such as retention of the afterbirth, the veterinary surgeon should be sent for at once.

An agglutination test of the blood will reveal whether animals are really affected, and this may be carried out at any time except within a few days after aborting. If the suspected animals are found to have the disease, the whole herd should be tested. The infected animals revealed by the test should be immediately isolated. The non-infected animals will then form the basis of an abortion-free herd. It will take time, but it is well worth while where an outbreak has occurred. If the contagion is widespread throughout the herd, the use of a live vaccine on one or two occasions should be resorted to for the production of Immunity . Heavy dischargee following abortion should be treated at once by the veterinary surgeon. If no new animals are introduced, the disease will die out of a herd. The purchase of calves should introduce new blood, a-s it is unsafe to introduce adults unless they have been tested and proved free from infection.