Journal of the Department of Agriculture. 



THE PREVENTION OF CONTAGIOUS ABORTION 



IN CATTLE. 



By E. M. Robinson, M.R..C.V.8., Veterinary Research Officer, 

 Veterinary Research Laboratory. Onderstepoort. 



In view of the great importance of cattle-breeding to tiie future of 

 South Africa, a popular article on the pTevention of contagious 

 abortion in cattle should prove very useful to stock-owners. The 

 present position as regards the distribution of the disease is that there 

 are very few parts of the Union which have no infected farms. Not 

 only does the disease spread rapidly through dairy herds, but under 

 ranching conditions on some of the largest cattle farms in the country 

 it has swept right througdi the herds, reducing the annual increase 

 by births of calves to practically nothing for two or three successive 

 years. Amongst the natives' cattle in the western and noTthern 

 Ti-ansvaal the disease has, in many places, become more or less 

 endemic, and an equilibrium has been reached, so that a fair number 

 of abortions occur annually, but most of the cows calve normally. 

 The danger of further spread is a very real one, as at present a great 

 many farmers do not realize the danger of buying cows from other 

 farms without first finding out whether those farms are free from the 

 disease or not. 



As this article is chiefly devoted to preventive measures against 

 contagious abortion, it will not be necessary to give a long description 

 of the symptoms of the disease, as these have been given fully in a 

 bulletin by Sir Arnold Theiler (Local Series No. 25, 1918, Department 

 of Agriculture, Union of South Africa). In the ordinary case a cow 

 or heifer will, without any previous symptoms, abort, the foetus 

 usually being at about the seventh month of pregnancy. Premature 

 calving may take place at any time during the 280 days of the 

 gestation period, wherein lies one of the chief dangers, as, when 

 abortion occurs in the first three months of pregnancy, the foetal 

 membranes practically always come away with the foetus, and unless 

 the cow is tied up in a stall, the foetus may never be seen and the 

 cow will shortly afterwards come in season again. Unless an owner 

 is on his guard such a case may be overlooked and the cow simply 

 considered as not having held to service. After the fourth or fifth 

 month of gestation it is usual for the afterbirth to be retained after 

 an abortion, and there is usually a brownish discharge from the 

 vagina, sometimes containing small yellowish lumps, but there may 

 be very little discharge at all. A further source of danger is the 

 cow which calves at the right time, but gives birth to a calf, normal 

 in size, but weak, and retention of the afterbirth occurs. Some 

 cows will even give birth to strong healthy calves and not retain the 

 afterbirth for more than twenty-four hours. Such animals are a 

 dangerous source of infection to uninfected stock, as they have infected 

 afterbirths and spread infection, althougli not to the same degree as 

 a cow with the typical symptoms does. Practically without exception, 

 infected cows harbour tlie organism of contagious abortion in the 



