Dystokia 571 



of fetuses in the uterus, any one of which, except the first, 

 which is the most dangerous, is almost equally liable to cause 

 difficulty in birth. Should dystokia occur from one of the first 

 fetuses to be expelled, it inevitably blocks the passage of the fol- 

 lowing fetuses, either from both horns, if lodged in the uterine 

 body or in the vagina, or from the involved horn in case it be- 

 comes arrested in its passage before leaving the cornu. In spite 

 of this fact, however, dystokia in these small animals, as we have 

 already stated, is very rare, with the exception of those which 

 are closely housed. 



The importance of dystokia, as related to the possibility or 

 probability of delivery, as well as to the recovery of the mother 

 and the life of the fetus, varies greatly according to species. 

 Among our domestic animals dystokia in the mare easily takes 

 first place in its seriousness as affecting the life and well-being 

 of the dam and still more in relation to the life of the fetus. The 

 great seriousness of dystokia in the mare is largely dependent 

 upon the tumultuous character of labor and her susceptibility to 

 infection, as well as upon the differences in the conformation of 

 the fetus, which renders an adjustment more difficult and injuries 

 to the uterus or other parts more liable to occur. 



Parturition is so tumultuous in the mare that serious and fatal 

 injuries may occur to her in a very short time, frequently long 

 before the obstetrist can arrive, even if called by the owner with- 

 out delay. This is in sharp contrast to the cow, in which serious 

 injury from labor is not liable to occur until a number of hours 

 have passed. 



The exceedingly rapid birth in the mare tends constantly to 

 produce ruptures of the uterus, in which the wounds penetrate 

 the peritoneal cavity and, as a general rule, end fatally for the 

 mother. In the cojv these penetrant wounds of the peritoneal 

 cavity rarely occur directly from the labor, and even when they 

 do they are not nearly so fatal as in the mare. 



The tendency to infection in the mare is very much greater 

 than that noted in the cow and constantly assumes a more serious 

 aspect for the life of the animal. 



The length of the extremities of the young foal tends con- 

 stantly to increase the difficulty of labor in all cases of vicious 

 position, because they are far more difficult of adjustment, so 

 that embryotomy is more frequently required. Not only are the 



