Persistent Mating-Induced Endometritus
Chronic non-suppurative endometritus occurs when anything is done to the uterus which causes a uterine inflamation (breeding, antibiotics). A transient inflammation following insemination is a normal reaction to sperm and noncellular debris introduced into the uterus during breeding. In normal mares, the transient endometritis is cleared within 24-72 hr post insemination. The uterus is able to support the embryo when it enters the uterus at 5-6 days.
If the uterus is not able to clear itself of the fluid/ bacterial infection then the uterus is not able to support the embryo when it enters the uterus. Treatment of these mares includes planning a single breeding one to three days prior to ovulation (cooled, fresh semen) to allow fluid to be evacuated from the uterus. Administration of oxytocin every 4-6 hrs after breeding cause uterine contractions to evacuate the uterus of unwanted fluid. Ultrasound evaluation on the day after ovulation to assess uterine fluid allows the veterinarian to lavage the uterus with sterile saline or saline + antibiotics and oxytocin treatment to clear the uterus.
