570 Veterinary Obstetrics 



from dystokia. Hence among all domestic animals the dairy cow, 

 which is frequently kept closely confined in a stanchion year in 

 and year out, easily takes the first place of importance in refer- 

 ence to difiicult labor. Cows of the same or similar breeds, when 

 not so closely confined nor so intensely used for dairy purposes, are 

 not so subject to these accidents, while in beef cows, which are 

 habitually permitted to run at large throughout the year, dys- 

 tokia is apparently almost, if not quite as rare as in any domestic 

 animal. 



The frequency of dystokia as related to environment is greatly 

 emphasized by observations upon the bitch and cat. In agri- 

 cultural communities, where these animals are habitually out of 

 doors daily and lead an active life, dystokia is almost unknown \ 

 whereas, in pet females which are kept closely confined in the 

 city houses, dystokia is frequent. In Illinois, though we were 

 in an extensive swine breeding district, dystokia in the sow 

 was almost unknown to us. In New York State, where swine 

 breeding is very limited, but the sows are kept closely confined 

 in styes, dystokia is comparatively common. 



We are not prepared to state exactly the reasons for these 

 differences in the frequency of dystokia as modified by environ- 

 ment. Fundamentally, it seems that the proper development of 

 the young is largely dependent upon the freedom of the mother 

 during gestation, as is shown by the fact that aberration in de- 

 velopment, such as double monsters, and other teratologic con- 

 ditions, are most frequently observed in those animals which are 

 closely confined. The general system, as well as the generative 

 organs of the pregnant female, does not preserve its normal vigor 

 whenever the animal is closely cbnfined by housing, and so when 

 parturition arrives the mother does not possess the needed vigor 

 for the expulsion of the young. 



The influence of the number of young at a given birth upon 

 the occurrence of dystokia does not seem to be of very great im- 

 portance. In the cow, ewe and goat, twins may simultaneously 

 approach the pelvic inlet and, by one or more of the extremities 

 of each entering the pelvis, may bring about dystokia, but this 

 is not very common. In multiparous animals, the simultaneous 

 entrance of two fetuses into the pelvis does not readily occur, and 

 dystokia is dependent upon the individual fetus, so that the 

 possibility of difficult birth is simply multiplied by the number 



