Results of insemination of mares with fresh and frozen stallion semen.

This research looked at the success rate of artificial insemination in mares using both fresh and frozen stallion semen, finding that despite suboptimal conditions, a significant percentage of mares still conceived and gave birth to live foals.

Introduction to the Experiment

• The research study was conducted in 1973 where 116 mares were artificially inseminated.
• The semen used for the process was deep-frozen and obtained from eight different stallions of the Hanoverian breed.

Challenges and Limitations

• The majority of the mares used were considered subfertile, which typically makes conception more difficult.
• The quality of the semen was lower than optimal due to it being frozen, which tends to reduce its viability for successful fertilisation.
• Some mares were inseminated during only one oestrus cycle, reducing the chances of successful fertilization.

Results of the Study

• Despite these significant roadblocks, 44% of the mares managed to conceive and give birth to a live offspring.
• This result indicates that even under suboptimal conditions, artificial insemination using frozen semen can be successful.

Comparison with Fresh Semen Insemination

• As a comparison, a smaller group of ten mares were inseminated with fresh semen in the same year.
• Of these, seven managed to conceive, suggesting that fresh semen might yield a higher success rate, although the sample sizes between the two groups are not comparable.

Conclusion and Implications

• The results of this study suggest that while suboptimal, the success of artificial insemination using frozen semen remains a viable option for horse breeding, particularly when fresh semen isn’t available.
• However, future research would benefit from larger sample sizes and a more direct comparison between the use of fresh and frozen semen for insemination.