Evaluation of two treatments in superovulation of mares.

This research study aims to analyze the efficacy of two hormone treatments in stimulating the superovulation of mares. Despite disparities in luteinizing hormone (LH) content, no significant differences were noted between mares treated with enriched follicle-stimulating hormone (feFSH) and equine pituitary extract (EPE), though both treatments surpassed the control group in terms of ovulation rate. Unexpectedly, embryo recovery rate remained unimpacted by these treatments.

Study Design and Group Allocation

• The study was conducted over two consecutive estrous cycles, the initial cycle serving as control.
• Ten mares were arbitrarily split into two groups, each consisting of five mares. One group was administered with feFSH, and the other with EPE.
• Both treatments contained equal follicle-stimulating hormone (FSH) quantities but varied in the luteinizing hormone (LH) amount.

Treatment and Process

• From Day 6 following ovulation, mares received daily doses of either 25 mg feFSH or EPE treatment.
• These treatments were halted once the mares cultivated one or two follicles of at least 35mm in diameter in control and treatment cycles, respectively.
• Consequently, a one-time injection of 25 mg EPE was given to induce ovulation.
• Every second day, until the detection of the final ovulation, mares were inseminated.
• A week after ovulation, non-surgical embryo recovery was performed in both control and treatment cycles.

Results and Conclusion

• Statistical analysis determined no significant differences in mare ovulations between the feFSH and EPE treatment groups. However, both groups demonstrated higher ovulation rates than the control cycle.
• Interestingly, the amount of embryos retrieved per ovulation remained similar across the control, feFSH, and EPE groups, indicating that the superovulatory treatments did not impact this aspect.
• The high LH content in the EPE treatment was observed to not influence the superovulatory response of the mares.
• The study concludes that while superovulatory treatments can amplify the ovulation rate in mares, they may not necessarily affect the embryo recovery rate per ovulation.