DIAGNOSIS 197 



the early stages of pregnancy the foetus will be expelled enclosed 

 in its membranes, but when the abortion occurs after the fifth 

 month of gestation the membranes (afterbirth) are usually 

 retained. The large percentage of abortions take place between 

 the fifth and seventh months of pregnancy, although abortion 

 may occur any time during the period of gestation. Great ex- 

 citement may be noticed in heifers following an abortion and at 

 times will show all the signs of the heat period. The discharge 

 from the uterus and vagina, following abortion, continues for 

 two or more weeks, and may continue longer when the inflam- 

 mation of the lining of the uterus becomes severe. The dis- 

 charge is of a dirty, yellowish gray color, tenacious in character, 

 and accumulates on the tail and other parts to which it may come 

 in contact. The appetite is impaired but gradually improves 

 as they recover from the effects of the abortion. The milk flow 

 is slight but increases gradually as the animal recovers. The 

 foetus is, as a rule, born dead or if alive is weak and undersized 

 and dies within a few days with symptoms of diarrhoea or re- 

 mains in a stunted condition. Cases in which the foetus has be- 

 come mummified occur in infectious abortion. Such cases are, 

 however, rare. In a number of cases, cows that have appar- 

 ently recovered from the effects of the disease fail to conceive 

 though served by the bull numerous times before becoming im- 

 pregnated, or may never again get with calf (non-breeders). 



Sterility in the greatest percentage of cases is probably 

 due to pyometra (pus in the uterus), the result of retained 

 placenta or afterbirth. In other cases the ovaries undergo cystic 

 degeneration, which, if extensive, often causes the cow to be 

 constantly bulling. Cases of this type are, as a rule, non- 

 breeders. Sterility is one of the chief characteristics of 

 infectious abortion. 



Diagnosis. — In a herd where several calves have been 

 aborted in an immature condition, and especially if the aborting 

 animals be heifers, one is usually justified in regarding the 

 condition as infectious. The history, of course, should be taken 

 into consideration. Where infectious abortion cannot be diag- 

 nosed clinically, the following methods of diagnosis have been 

 recommended: (1) Bacteriologic. (2) Serologic. 



