472 Veterinary Obstetrics 



on slippery, wet floors, there may at any time occur a slip or 

 fall which may imperil the life of the fetus. 



Mechanical injuries leading to abortion are more common in 

 uniparous animals, because in these the uterus is more fixed in 

 its position and does not yield so readily to external forces. 

 Moreover, it is in these animals that we most frequently observe 

 injuries, either at work or in transport, as they offer greater ^ 

 difficulty in handling. When they fall, their greater height and 

 weight increases the impact and intensifies the strain upon the 

 placental attachments. The greater size and weight of the fetus 

 concentrates its impact upon a comparatively small area and in- 

 creases the injury to the placenta. 



The recognition of an impending abortion is usually diflScult 

 until near its completion. Usually the abortion occurs before 

 the owner or caretaker has become aware that it is threatened, 

 so that the first evidence which is observed is the fact that the 

 abortion has taken place, as is shown by the presence of the 

 expelled fetus and membranes. In cases where a number of 

 pregnant females are kept together, it may even be diSicult to 

 determine which one has aborted, except there can be found 

 some marks upon the animal, consisting usually of soiled tail, 

 perineum and thighs, due to blood and fetal fluids discharged 

 from the genital canal. 



In other cases the threatened abortion is indicated by swelling 

 of the vulva and a muco-purulent discharge, accompanied some- 

 times by swelling of the udder. The symptoms increase general- 

 ly as the duration of pregnancy increases, so that when a late 

 period of pregnancy has been reached the symptoms are similar 

 to those of normal birth. Rarely the expulsion of the fetus 

 does not occur until some time after its death and there 

 may be swelling of the udder, with secretion of milk, for days 

 or weeks before the fetus is finally expelled. Sometimes in the 

 mare, there is observed swelling of the udder and secretion of 

 milk without apparent cause, which continues for several days 

 and finally disappears. I,ater, in the course of some weeks, the 

 mare aborts twins, one of which is found to be much less de- 

 veloped than the other. This suggests that the one had perished 

 at the time when the swelling of the udder was noted, but had 

 not been expelled, and the other had continued to live and grow 



