​Analysis of Uterine and Systemic Parameters in Fertile and Barren Mares

Background: Breeding success in mares is dependent on both local and systemic factors. Uterine conditions such as endometritis have a negative impact on fertility. Similarly, poor body scores and systemic inflammatory conditions are associated with reduced pregnancy rates. This study aimed to investigate differences in uterine and systemic status between fertile and barren mares. Methods: Uterine ultrasonographic findings, endometrial cytology, body condition score, rectal temperature and complete blood count were evaluated in sexually mature fertile (n=15) and barren (n=15) thoroughbred mares. Differences in the mean values of various parameters between the two groups were evaluated for statistical significance through independent t-tests using commercial statistical software. Result: Compared to fertile mares, barren mares had a significantly higher number of neutrophils and a significantly higher neutrophils: epithelial cell ratio as per endometrial cytology. The ultrasonography revealed presence of uterine fluid in 12 out of the 15 barren mares. Uterine fluid was not observed in any of the fertile mares. No differences in body condition score, rectal temperature and complete blood count were observed between the two groups. These results suggest that infertility in mares results predominantly from alterations in the uterine health.