THE MORE COMMON AILMENTS OF CATTLE 429 



occurs in the best managed herds. It usually clings so 

 persistently to a herd and remains for so long a period, 

 generally not fewer than two or three years, that it has 

 come to be a veritable nightmare to breeders where it 

 has become prevalent. It entails loss, first, in the calves 

 that fail to come to birth ; second, in the greatly dimin- 

 ished milk flow resulting from the absence of freshen- 

 ing and from the debility that results from abortion, and, 

 third, in the great expense and labor involved in main- 

 taining animals apart and in disinfecting the stables and 

 also the cows. Next to tuberculosis, it would seem 

 correct to say this disease entails the most loss upon 

 those who keep cattle. 



The preventive measures that may be adopted to 

 protect cows against non-contagious abortion include 

 the avoidance of the causes given above. In other 

 words, they include intelligent breeding where breeding 

 is practiced and management watchful and intelligent 

 all along the line. Where these measures are followed, 

 there will be few instances of abortion. But these, 

 though helpful, are no certain protection against con- 

 tagious abortion. 



The more important of the protective measures against 

 infectious abortion are the following: (i) When purchas- 

 ing or breeding animals, seek vigorous development; (2) 

 When purchasing animals, make sure that they come 

 from sound herds. (3) In no instance use a bull unless 

 assured that he has not served infected cows. (4) Use 

 disinfectants where the disease has appeared, promptly, 

 wisely, and perseveringly. The importance of vigor in 

 relation to successful breeding is so constant that the 

 aim should be to maintain vigor as far as possible by 

 careful feeding in the infected herd. It should be pos- 

 sible for owners of cattle to be sufficiently vigilant with 

 reference to the introduction of other cattle into their 

 herds, and also the use of males, as to prevent this dis- 

 ease from getting a foothold. AVhen a cow has aborted, 



