Chapter VIII 

 PARTURIENT INJURIES 



A. Lacerations of the Perineum 



Lacerations of the perineum occur in two distinct ways, 

 and almost exclusively in mares. The more important type 

 of laceration of the perineum is due to one of the extremi- 

 ties of the fetus, generally a foot, becoming misdirected 

 during parturition, being forced up through the roof of the 

 vagina and floor of the rectum, and protruding from the 

 anus. The violent expulsive efforts of the mother drive the 

 fetus along and tear asunder the entire partition between 

 the rectum and the anus above and the vagina and vulva 

 below, converting the two posterior openings into a common 

 cloaca. The accident and its handling have been fully de- 

 scribed in the companion volume, Veterinary Obstetrics. 

 It is referred to here because, as a general rule, if not prop- 

 erly handled, it closes the breeding life of the animal. The 

 unhealed tear permits feces to drop into the vagina, keep- 

 ing up a constant irritation and fecal infection. It also 

 renders copulation virtually impossible. If the cervix and 

 uterus are healthy, artificial insemination may succeed, and 

 if pregnancy ensues the injury will offer no impediment to 

 parturition. 



The second type of laceration of the perineum may occur 

 in any animal, though most frequently in the mare. In this 

 type of laceration, the injury is due to overstretching of the 

 vulva by the volume of the fetus. In almost all cases the in- 

 jury occurs at the superior commissure of the vulva and ex- 

 tends obliquely upward to the right or to the left outside the 

 anal sphincter. Such lacerations are of importance princi- 

 pally because they permit the superior commissure of the 

 vulva to drop forward, rendering the vulvar opening hori- 

 zontal and interfering with copulation. Still more impor- 

 tant, they destroy the physiologic function of the vulva as a 

 sphincter and as a barrier to infection, so that the vagina 



