Uterine lavage can be performed immediately prior to artificial insemination in mares without adversely affecting fertility, according to a recent study completed at the University of Idaho (UI) in Moscow, Idaho. The uterine lavage process is used to clear the uterus of inflammatory fluids that could decrease the viability of semen in mares.

Researchers already knew that uterine lavage could be performed as soon as four hours after insemination without adversely affecting fertility, but the effect of performing lavage immediately prior to insemination had not been reported until the current study, which appeared in the April 15 issue of the Journal of the American Veterinary Medical Association.

Persistent mating-induced endometritis is a fairly common reproductive problem, especially in older mares, and it is a prime cause of inflammatory fluid in the uterus, according to Dirk K. Vanderwall, DVM, PhD, Dipl. ACT, assistant professor in the Department of Animal and Veterinary Science at UI and lead investigator in the study. Diagnosis is best made by transrectal ultrasound and “is based on the finding of an ultrasonographically detectable amount of the fluid in the uterus that is characterized by a gray appearance in an ultrasound, correlated with an increased cellularity of the fluid, indicative of an inflammatory process in the mare’s uterus.

“Quite frequently, I had been clinically faced with the situation of needing to breed a mare when she had inflammatory fluid in the uterus,” Vanderwall said. “I was in a quandary, knowing that I needed to do a lavage to get the fluid out, but at the same time wondering would the lavage process or the solution itself adversely affect the semen? This is a real-life scenario faced by the breeder and the veterinarian, and now we have an answer that gives us an understanding of the suitability of this particular process