THE MORE COMMON AILMENTS OF CATTLE 427 



animals be introduced into the herd unless they have 

 first been tested or come from herds guaranteed free 

 from the disease. The wide dissemination of tubercu- 

 losis has arisen more from the introduction into herds of 

 tuberculous pure-bred cattle, and especially pure-bred 

 males, than from any other source. If such action were 

 to become general, the owners of pure-bred herds who 

 refuse to test their cattle would have to go out of busi- 

 ness and this dread disease would be greatly circum- 

 scribed. 



Abortion in cows. — In the strict sense abortion 

 means the expulsion of the fetus before it can exist 

 independently of the dam, but more commonly the term 

 is used to indicate the expulsion of the fetus at any time 

 previous to the usual completion of the period of preg- 

 nancy. Such expulsion, after the offspring is capable of 

 existence apart from the dam, is more accurately ex- 

 pressed as premature birth. Abortion is of two kinds, 

 viz., sporadic, that is, occurring singly and non-infec- 

 tious, and infectious. Non-infectious abortion may lead 

 to considerable loss in the aggregate, but should not be 

 serious in any individual herd. On the other hand, in 

 certain areas, infectious abortion has come to be, in a 

 sense, a scourge, especially pure-bred cattle. While 

 abortion may occur at any time, its occurrence is less 

 frequent previous to the third month of conception. 



Prominent among the causes of non-contagious 

 abortion are: (i) Mechanical injuries such as may 

 arise from slipping, jamming in doorways, and being 

 hooked by other cattle and kicked by horses; (2) exer- 

 cise violent or sudden such as the animal is not accus- 

 tomed to; (3) indigestion in its various forms which 

 usually results from feeding food unsuitable in kind or 

 badly cured ; (4) ergotized grasses, smut in fodders, 

 foods that are frozen or so lacking in succulence as to 

 induce constipation ; (5) administering strong medicines, 

 especially purgatives; (6) water that is putrid from 



