Aim to place all pregnant animals in disinfected individual pens or stalls a few days before they are expected to calve, and confine them to these quarters for three or four weeks following the delivery of the calf, or as long thereafter as uterine discharges are observed. Avoid carrying infection from the maternity stalls to other portions of stable, on shoes or otherwise. This may be prevented to some degree by the use of disinfectant solutions on shoes after the stalls have been entered or by wearing rubbers while in the maternity stalls, removing them after the isolated animals have been attended to. The isolation of cows at time of calving and the aborting animal is based upon the knowledge that the fetus, afterbirth, and uterine discharges of an affected animal at these times very frequently contain myriads of the abortion bacteria, and that unless these substances are confined and promptly destroyed an abundant opportunity is provided for the contamination of the food substances of the healthy animals and their contraction of the disease.
Refrain from breeding fresh cows for a period of six weeks to two months following calving. The aborting animal should be isolated for a period of six weeks to two months and under no consideration be permitted to mingle with the rest of the herd as long as uterine discharges are observed.
Douching of the external genitals of the bull, a practice formerly regarded as highly important for preventing the spread of the disease, is now recognized as being of doubtful value. The bull is protected from abortion infection to a great degree by permitting him to serve only such animals as have calved or aborted from six weeks to two months previously. Investigational work has indicated that when the bull is affected with the disease the organs of his generative system commonly involved are not reached by the antiseptic solutions. A more rational method for the prevention of the spread of the disease by the bull consists in keeping him in an inclosure separate from the females and in having all services take place on neutral ground.
Great care should be used in purchasing cattle, and cows not known to be free from the disease should be kept in separate quarters until this point is determined.
GRANULAR VENEREAL DISEASE (INFECTIOUS GRANULAR VAGINITIS).
The affection to which the foregoing names have been given is a chronic, mild, and apparently contagious disease of cattle, characterized by an inflammatory condition of the mucous membrane of the vagina and the development of nodules upon its surface.
This disease is very widely spread, but from an economic point of view it does not appear to have great significance. Williams, who investigated it, asserts that it is difficult to find a single herd in this country which is free of this disease. He considers it of great importance, claiming that granular vaginitis has a vital relation to abortion. This view, however, is not substantiated by other investigators, it being now generally accepted that the disease is only rarely responsible for abortion, and further, that it exerts no apparent ill effects on the health of the animal and that it has no effect on the milk yield.
Symptoms.—Natural infection may take place either by direct contact of animals or at the time of service. Most of the cows in the affected herd contract the disease, but the bulls are rarely or very mildly affected. The inflamed condition of the membranes of the vagina results in a catarrhal exudate, and this discharge, which soils the external genitals and the tail, and the uneasiness and sometimes the straining of the animal, are the first and most prominent symptoms observed. Upon examination, small, hard, grayish nodules can be seen and felt upon the inflamed membranes. This acute stage may last for three or four weeks, then it gradually subsides and assumes the chronic form, only to flare up again as the animal comes in heat.
These nodules are sometimes found on the membranes of the uterus, and some investigators have argued from this fact that it was responsible for abortion and sterility. Others, however, deny this and point out that the bacillus of abortion can be demonstrated in nearly every case. The importance of the disease is therefore in dispute and the decision must be left to future investigation.