114 BOVINE OBSTETRICS 



Expulsion of the Fcehis. — By means of the uterine contrac- 

 tions, the cervix uteri is opened and a part of the fcetal mem- 

 branes ia the shape of a bladder are driven into the genital 

 canal, in the Same manner as in normal parturition. The cervix 

 uteri is dilated less, while at the same time forms no obstacle 

 to the rather small foetus. We may say that in general the 

 same phenomena accompanies abortion as a regular birth, only 

 of lessened intensity. As a rule, the expelling forces need not 

 be supported by traction. The calf is often found lying in the 

 pasture, where the mother, of course, did not receive any aid. 



The presentation of the calf may be normal; that is, the 

 head rests upon the anterior extremities. Slow and insufficient 

 dilatation often leads to deviations, as a malposition of the 

 head or forelegs flexed at the knees. As a rule, reposition is 

 easy. The afterbirth usually is retained for some time after 

 birth of the calf. There are cases where the foetal membranes 

 (secundinse) are expelled six to twelve hours after parturition ; 

 their expulsion mostly is retarded, which may produce many 

 disturbances erroneously attributed to abortion. 



Why is the placenta retained as a rule ? First, because 

 the uterine conttactioiis are insufficient to detach the villi of 

 the foetal placenta from those of the maternal placenta; second, 

 because the union of the two placentse is too firm. We know 

 that even the physiological expulsion of the afterbirth in the 

 cow takes place under less favorable circumstances than with 

 other domestic animals. In abortion, those factors which 

 normally bring about exjDulsion in three to four hours after 

 parturition, act insufficiently. When abortion is a sequel to 

 diseases of the placenta, where, as the result of a placentitis or 

 apoplexia placentae, the villi become united by fibrous tissue, 

 retention of the placenta after parturition is a rule, and manual 

 removal of this afterbirth becomes exceedingly difficult. 



As a consequence of the retention of the placenta after 

 parturition, metritis, acute puerperal infection, leucorrhoea and 

 pyaemia may arise. (See " Eetentio Secundinarum.") 



Frognosis. — Abortion in the second half of the period of 

 gestation usually does not endanger the life of the animal. 



