Histomorphological endometrial status and influence of oxytocin on the uterine drainage and pregnancy rate in mares.

The study explores the effect of oxytocin, a hormone that influences uterine contractions and fluid drainage, on the fertility rates of oestrous mares. It was found that administering oxytocin to mares with fluid buildup in their uterus improved their chances of successful pregnancy.

Research Objectives

• The research aimed to understand the impact of different doses of oxytocin on the fertility of mares, specifically their uterine drainage during their oestrous cycle.
• It also sought to histomorphologically examine endometrial biopsies of mares with or without fluid accumulation in the uterus around ovulation time to understand the potential susceptibility to infection.

Methodology

• A total of 59 Hanoverian Warmblood mares were used in the study. They were separated into two groups – Group A (49 mares with fluid buildup in the uterus) and Group B (10 control mares without fluid accumulation).
• Group A was further divided into three subgroups based on the dosage of oxytocin administered (none, 15 i.u., 25 i.u.).
• Before insemination, each mare underwent rectal palpation, ultrasonography, and vaginal inspection. In addition, plasma hormone concentrations of estradiol and progesterone were evaluated during ovulation.
• All mares had endometrial biopsies, with only mares in Group A undergoing microbiological and cytological evaluation of the samples. The mares were inseminated in proximity to ovulation during the first cycle.

Findings

• The study found that mares with intrauterine fluid accumulations who were treated with oxytocin intravenously had higher chances of achieving pregnancy than mares who did not receive this treatment.