Influence of Eqvalan (ivermectin) on quality and freezability of stallion semen.

This is a study on the impact of Eqvalan (ivermectin) on the quality and ability to freeze stallion semen. The results suggest that Eqvalan not only does not negatively impact semen quality and freezability, but seems to significantly improve most examined sperm parameters.

Methodology

• The study was performed on 22 Freiberger stallions, divided randomly into a control group and a test group.
• The experiments took place over 17 weeks from October 1997 to February 1998, during which semen was collected once per week from the stallions.
• The stallions in the test group were administered a therapeutic dose of Eqvalan orally at a rate of 0.2 mg ivermectin per kg.
• The scrotal width was measured and ejaculates were collected to determine various parameters such as volume, concentration, motility, and morphology (including normal sperm, major defects, vacuoles, and acrosome defects).
• Frozen-thawed semen samples were also assessed for motility and viability using fluorescence staining with propidium iodide/SYBR-14.

Findings

• Stallions that were treated with Eqvalan displayed significantly better concentration and motility in fresh semen compared to the control group.
• Following freezing-thawing, the viability and motility of semen in treated stallions also increased noticeably.
• In terms of morphology, variables such as normal sperm, major defects, and vacuoles were significantly improved in the Eqvalan group.
• Apart from the differences noted in groups, a temporal effect was also recorded on morphological features. Both groups showed a decrease in normal sperm and an increase in major defects over the course of the experiment.

Conclusions

• The results of the study suggest that a single oral application of Eqvalan did not negatively impact the quality or ability to freeze stallion semen during the nonbreeding season.
• Instead, it appears Eqvalan has a beneficial effect on the fertility of stallions as most of the sperm parameters investigated were significantly better in the group of stallions treated with Eqvalan.