On Abortion in Cows. 



63 



days, or 46 weeks within one day ; that out of 577 individuals no 

 fewer than 20 calved beyond the 298th day, and that the shortest 

 period was 240 days. Earl Spencer^ in the " Journal of the 

 Royal Agricultural Society of England" for 1839, considers the 

 average period of gestation, as noticed in 764 individual cows, 

 to be 284 or 285 days; but 310 calved after the 285th day, 3 

 went to the 306th day, and 1 to the 313th. A cow pregnant 

 with a male calf is more likely to exceed the 40 weeks than she 

 is with a female. This is shown in Earl Spencers observations; 

 he found that among calves born between the 290th and SOOth 

 day, there was a preponderance of males in the proportion of 

 74 males to 32 females. It has been found in the human 

 female, as well as in the cow, that the period of the first gestation 

 is frequently shorter in duration than subsequent ones. This 

 probably depends on the uterus of a young female not being 

 adapted for that amount of expansion of which it is rendered 

 capable by repeated pregnancy. Calves born before the end of the 

 seventh month seldom survive, even if born alive, and it is rarely 

 desirable that they should live if born before the end of the 

 eighth month, as their weakness and diminutive size render them 

 comparatively valueless. 



The cow usually produces but one calf at a birth. Very 

 numerous instances occur, however, in which twins are born, and 

 if these be one a male and the other a female, the latter is gene- 

 rally (and according to popular opinion in some districts, invari- 

 ably) incapable of breeding. Such females are called free 

 martins, and are evidently the same animals which Columella 

 (lib. vi.) calls taurce, probably from their approximation in certain 

 points to the formation of the bull. It is now well known that 

 many of these females are capable of breeding. Recorded cases, 

 proving this to be the fact, are to be found in the " Philosophical 

 Transactions," vol. Ixix. p. 289 ; in Professor Owen's edition of 

 Hunter's Observations," 1837 ; and in the " Farmer's Maga- 

 zine " for November, 1806. Occasional cases occur in which 

 cows produce three calves at once ; and in the " Nouveau Bulletin 

 des Sciences" an account is given of nine calves having been pro- 

 duced at three successive births by one cow. 



Although abortion is the term which the professional man 

 employs to signify a premature expulsion of the uterine contents, 

 yet, as applying to the cow, numerous other names are in daily 

 popular use to signify this condition. Some of the most common 

 are these : — Slippirig calf, slinking calf picking calf casting calf 

 and warping. 



Abortion in the cow may take place at any period of gestation, 

 but is most common between the ninth and fifteenth weeks. It 

 may occur before the germ or ovum, from which the future 

 animal is formed, has assumed any of its permanent characters. 



