Effect of Timing of Postovulatory Insemination Relative to Human Chorionic Gonadotropin/Buserelin Treatment With 1 Straw of Frozen-Thawed Semen on Mare Fertility.

The research explores the impact of timing when inseminating mares using frozen semen, in relation to the treatment with human chorionic gonadotropin/buserelin, on their fertility. The study particularly focuses on how the interval between ovulation checks and the type of ovulation-inducing drug used affects the success of pregnancy and likelihood of early embryonic loss. It finds that neither the timing of checks nor the drug utilized had a significant impact on these rates.

Aim of the Study

• The chief aim of this retrospective study was to understand if the interval between examinations to detect ovulation impacts the likelihood of pregnancy and early embryonic loss in horses. These checks were carried out postovulatory insemination with a single straw of frozen or thawed semen.
• The secondary objective involved establishing the effectiveness of two individual drugs (human chorionic gonadotropin and buserelin) in inducing ovulation in a timely manner.

Methodology and Variables

• The study was conducted retrospectively, which means it analyzed data that was previously collected, potentially not specifically for this research purpose.
• The research considered various parameters, including the interval from the second last check to ovulation, the ovulation-inducing drug used, the number of the cycle, and the stallion as potential factors affecting pregnancy and embryo loss rates.

Study Findings

• The research established that the length of the interval from the second last check to the actual ovulation did not significantly impact either the pregnancy or the early embryo loss rates.
• This finding was consistent across different time frames (4 hours, 8 hours, and 16 hours).
• The study also found that the ovulation-inducing drug used, the cycle number, or the stallion did not significantly affect the fertility outcomes.

Conclusion

• The study concludes that there is no apparent advantage in checking horses for ovulation during late evening and night hours, particularly when postovulatory artificial insemination and ovulation-inducing drugs are being used.
• Such a conclusion suggests that the processes can be made less laborious and possibly cost-efficient, without significant impacts on the fertility outcomes.