Aspiration of equine oocytes from immature follicles after treatment with equine pituitary extract (EPE) alone or in combination with hCG.

This article presents a study on the impact of administering equine pituitary extract (EPE) either alone or alongside hCG on the recovery rate of immature follicles in mares. Superovulation methods increased the number of follicles available for aspiration and concrete disparities in terms of follicles with expanded granulose cells expansion were observable when EPE/hCG treatment was used as opposed to just EPE or no treatment.

Research Method and Procedure

• The research was conducted on ten crossbred mares aged between 3 to 15 years and weight ranging from 350kg to 400kg.
• The mares were subjected to three different treatments in random sequence, with each new treatment separated by a rest cycle that included spontaneous ovulation.
• Three treatments were applied to the mares for the study. The first treatment involved superovulating the mares with 25mg of EPE and administering 2500 IU hCG. The second treatment was a superovulation method using 25mg of EPE alone, while the third treatment was the control where no exogenous treatment was applied.
• These treatments were applied seven days after spontaneous ovulation took place.
• All the follicles that were at least 10mm in size were aspirated 24 hours post the largest follicle achieving a diameter ranging between 27 to 30 mm in the control group. In contrast, other follicles reached 22mm to 27mm for the EPE treatment.
• For the group subjected to EPE combined with hCG, hCG was administered 24 hours before ovum pick-up (OPU) after the follicles grow between 22 to 27 mm.

Research Findings

• The superovulation process increased the number of follicles that were available for aspiration. In the EPE/hCG group, 61 follicles were available for aspiration. For the EPE-only group, the number of follicles available was 63 while the control group had 42 follicles available.
• The proportion of aspirated follicles fluctuated between 63.5% and 73.8% .
• The oocyte recovery rate varied between 15.0% and 16.7%. The proportion of mares that yielded at least one oocyte was found to be 70% in the EPE/hCG group, 60% in the EPE group, and 50% in the control group.
• A higher proportion of follicles with expanded granulosa cells were observed in the EPE/hCG treatment group (64.4%) when compared to the control group (3.3%) and the EPE-only treatment group (25.0%).
• Superovulatory treatment resulted in a notable increase in the interval from aspiration to ovulation, from 15+/-4 days for the control group to 27+/-15 days for the EPE group and 23+/-13 days for the EPE/hCG treatment group.