Incidence Rate and Effects of Persistent Mating-Induced Endometritis (PMIE) in Quarter Horse Mares

The goal of this retrospective study was to determine if a relationship exists between mare age and accumulation of intrauterine fluid after breeding and if this fluid affects pregnancy rates in a clinical setting. The hypotheses were: a) older mares will have a greater incidence of intrauterine fluid retention 24 hours after breeding and b) a reduction in pregnancy rates will occur in mares that retain intrauterine fluid for greater than 24 hours after breeding. Mares were managed at the Equine Reproduction Laboratory at Colorado State University. Inclusion criteria for the study were as follows: Quarter Horse mares, ovulation within 48 hours of breeding, and pregnancy or embryo flush result recorded. Treatments for intrauterine fluid were performed at the discretion of the attending clinician. Data were compared by a contingency table utilizing Fishers Exact test. Data were presented as the mean +/- SD. The overall incidence of PMIE was 36%. A significant (p24 hours (Table). A significant reduction in pregnancy rates was observed in mares that had intrauterine fluid 48 hours after insemination compared to mares with normal or no fluid (34% vs 60%). There was no effect of intrauterine fluid on pregnancy rates within age groups (Table). There was a trend (p=0.052, 0.054, respectively) for an effect of age on conception rates for mares 16-20 and >21 years of age.   […]