Post-thaw motility and longevity of motility of imipramine-induced ejaculates of pony stallions.

This research studies how the freezing and thawing process affects the movement and life span of sperm collected from pony stallions, using imipramine-induced and normal in copula ejaculation methods. The findings suggest that imipramine-induced ejaculates, despite being much more concentrated and of a lower quantity could be suitably preserved through freezing.

Objective and Methods of the Research

• The main objective of the study was to understand the influence of the freezing process on the motility and longevity of sperm collected from pony stallions, using two different ejaculation methods- the imipramine-induced ex copula method and the natural in copula method.
• The imipramine-induced ex copula method involved inducing ejaculation outside customary mating or copulation, while in copula ejaculation involved natural mating or copulation.
• Sperm samples were collected from five pony stallions and were frozen in 5-ml straws, using an adjusted Kenney glucose skim-milk extender, a medium that aids in preserving the sperm while freezing.

Findings and Analysis

• The researchers examined the motility of the sperm right after unfreezing as well as the daily post-thaw motility, including both total and progressive motilities. The findings showed that the motility figures were similar for both imipramine-induced and in copula ejaculates.
• The count of days for the complete absence of progressively-moving spermatozoa was also similar for both methods of collection.
• The analysis further revealed that the morphology of sperm was alike for in copula and ex copula ejaculates, both before freezing and after thawing. Hence, methods of sperm collection did not influence its structure.
• Earlier studies also found that imipramine-induced ejaculates were marked by a denser concentration of sperm and a lower volume. This was also confirmed in this study.

Conclusion and Implications

• The results imply that despite being more concentrated and lesser in volume, imipramine-induced ejaculates could be effectively frozen for preservation, with no significant difference in motility compared to the naturally collected sperm.
• However, the researchers suggest that breeding trials are needed to establish the actual fertility of thawed semen, as they haven’t examined it in this study.