Persistent breeding-induced endometritis

Breeding-induced endometritis is a physiological reaction to semen. It is an important part of normal sperm transport to the oviduct as well as elimination of excess sperm from the uterus. In 10-15% of brood mares, the normal clearance mechanism fails resulting in a persistent breeding-induced endometritis with severe consequences on fertility. The cause of persistent breeding-induce endometritis is believed to be impaired myometrial activity in response to uterine inflammation. However, disruption of normal breeding activities may also contribute to the condition. Social interaction with a stallion appears to be important to normal uterine contractility after breeding. The presence of seminal plasma in an inseminate has also been shown to be of importance to normal sperm transport and elimination from the female tract, as well as in the modulation of the breeding-induced inflammation. Treatment of persistent breeding-induced endometritis has been focused on assisting the uterus to clear the inflammation in a timely fashion. Post-breeding treatments with oxytocin or prostaglandins and/or uterine lavage at 6-24 hours after breeding have been used by practitioners with good success. Alternative treatments such as the use of corticosteroids, immunostimulants, and acupuncture have recently been suggested to improve uterine clearance and fertility in mares that are susceptible to persistent breeding-induced endometritis. Regardless of the choice of treatment strategy, it is important to keep in mind that all mares develop breeding-induced endometritis after breeding, but only 10-15% of these mares develop a persistent form of the condition and would benefit from treatment.