Reproductive performance in mares subjected to examination by diagnostic ultrasound.

This study investigates the reproductive efficiency in horses when subjected to frequent ultrasound examinations over three years. The results indicate there’s no evidence of harm to preovulatory eggs or embryos from routine ultrasound usage, but it doesn’t necessarily provide improved reproductive efficiency.

Study Design

• The research was conducted over a three-year period, involving 1032 light horse mares. These equines underwent regular diagnostic ultrasound examinations with the data compiled with respect to their reproductive efficiency.

Key Findings

• A high cumulative pregnancy rate at 35 days post-ovulation was found to be 96.8%. This was determined by ultrasound examinations and potentially suggests that the procedure does not adversely affect the likelihood of a successful pregnancy.
• The pregnancy rate per cycle was found to be 76.0%, which suggests that in each breeding cycle, just over three-quarters of the mares were successfully impregnated.
• The average number of cycles per conception was 1.43 with an average of 2.29 insemination per cycle, indicating the average attempts required for successful breeding.
• The incidence of early embryonic death was recorded at 7.8%, indicating the possibility of negative outcomes in these reproductive cycles.
• Mares underwent an average of 5.04 scans during the follicular phase of the cycle, which indicates the stage in the cycle that ultrasounds were most frequently used.
• The average number of ultrasound examinations per mare, including pregnancy examinations, was approximately 10.

Interpretation and Conclusion

• Despite being an experimental study that did not use both control and treated mares, there was no evidence found that preovulatory eggs or embryos were damaged by routine ultrasound examination. This suggests that ultrasounds, when used correctly, are a safe practice in equine reproductive management.
• Comparing these findings with existing data from commercial facilities seems difficult due to possible differences in methodologies or other contextual factors.
• While this study suggests the relative safety of ultrasound examinations in equine reproductive management, it does not provide strong evidence for an improvement in reproductive efficiency as a direct result of ultrasound usage.