512 Veterinary Obstetrics 



The force of the uterine contractions is not very apparent to 

 the observer. The obstetrist recognizes them during parturition, 

 when he inserts his hand between the fetus and uterine walls 

 during labor. But, in cases of dystokia, the obstetrist does not 

 note so vividly the contractions of the uterus, but observes chiefly 

 the great pressure which is exerted upon his hand and arm when 

 the animal makes violent expulsive efforts by the contraction of 

 the abdominal walls and the increase thereby of the intra-abdom- 

 inal pressure. 



The uterine contractions dilate the os uteri, expel the fetus 

 unaided in case the contractile power of the abdomen is destroyed 

 by extensive rupture, and, after the birth of the fetus, expel the 

 placenta. 



By observing the contractions of the pregnant uterus when it 

 is exposed to the air, we find that the movements are of a char- 

 acter closely analogous to intestinal peristalsis. At what time 

 these contractions of the uterus begin, in relation to parturition, 

 we do not know. Probably contractions of a peristaltic type 

 occur continuously throughout the entire period of gestation, not 

 of a character to threaten the expulsion of the fetus, but of a kind 

 to favor its normal development and maintain its normal position. 



Fleming maintains that during the labor pains the entire 

 uterus contracts, but that the fundus does so most energetically. 

 This opinion is apparently drawn from human obstetrics, because 

 the uteri of domestic animals have virtually no fundus, and con- 

 sequently contractions could not occur chiefly in that part. 



Clinical observations upon the larger domestic animals would 

 indicate that contractions of the muscular walls of the uterus 

 frequently commence two or three days, or even longer, in ad- 

 vance of parturition, and that they are manifested by the appear- 

 ance of slight colicky pains. This is especially noted in the 

 mare, and suggests that labor is threatened and that there is 

 actually some pain present, due to the vigorous contractions of 

 the uterine muscles. These symptoms may appear in a very 

 mild form for several days in succession before real expulsive 

 efforts begin. As a general rule they pass unnoticed, and it is not 

 until there are added to the uterine contractions, the expulsive 

 powers of the abdominal walls that we really observe their 

 presence. 



