In September Mats Troedsson, DVM, PhD, Dipl. ACT, ECAR, professor and director of the University of Kentucky (UK) Gluck Equine Research Center and chair of the department of veterinary science, lectured at UK’s Veterinary Diagnostic Laboratory (UKVDL) on endometritis.

"Endometritis is a fine-tuned interaction between the host immune system and invading agent for which targeted treatment works best," he said. "It is important to distinguish between ‘normal’ and ‘abnormal’ mares, since only 10-15% of broodmares are susceptible to persistent endometritis."

Endometritis is an inflammation of the uterus lining that can be caused by breeding or introducing bacteria into the uterus. Typically, endometritis resolves quickly, but in some mares chronic, recurrent uterine inflammation is a persistent problem that can interfere with pregnancy.

"While most young mares have a remarkable ability to clear inflammation, older, multiparous (having foaled two or more times) mares can fail to clear contaminants from the uterus and are considered ‘susceptible,’ " Troedsson said.

Several issues can contribute to susceptibility. Impaired myoelectrical activity (electrical activity in the muscle) or other uterine pathologies, for instance, can delay uterine clearance (Woodward et al). Horizontal uterine placement allows the mare to more readily clear pathogens than pendulous (i.e., downward facing, or slanted) uterine placement. In studies, susceptible mares accumulated nitric oxide following induced inflammation, which impairs smooth muscle contraction, thereby inhibiting uterine clearance, T