Relationship among seminal characteristics, fertility and suitability for semen preservation in draft stallions.

This research paper investigates the relationship between seminal characteristics, fertility, and the suitability for semen preservation in 4 Draft stallions. Despite differences between the stallions in seminal volume, sperm morphology and motility, and fertility, no clear link was found between these factors. The study shows that the ability to preserve semen differs from stallion to stallion and is not related to fertility. It concludes that the suitability of individual stallions for semen preservation must be carefully assessed.

Sampling and Assessment

• The researchers evaluated the seminal characteristics, fertility, and response to semen preservation in 4 Draft stallions of Percheron and Breton breeds.
• Characteristics of semen such as gel-free volume, sperm concentration, sperm morphology, and the percentage of motile sperm were assessed in 5 ejaculates from each of the 4 stallions.
• Stallion fertility was retrospectively calculated based on the accumulated pregnancy rate over three breeding seasons.

Semen Preservation Study

• Five ejaculates from each stallion were subjected to liquid storage at 5 degrees Celsius.
• The percentage of motile sperm was assessed at 0, 24, 48, and 72 hours.
• Cryopreservation was performed using a glucose-EDTA-lactose egg yolk extender and a skim milk-based extender containing clarified egg yolk, with four replicates per stallion.
• The percentage of sperm with intact plasma membranes (IPM) and motile sperm were evaluated before and after freezing.

Findings and Conclusion

• Semen characteristics and fertility varied among the four stallions, but there was no evident relationship between these parameters.
• The response to liquid storage differed among stallions, and the best results were obtained from a stallion with the highest initial motility.
• The researchers found poor results for semen freezability using both freezing protocols (PMS range 13.8%-26.3%; IPM range 19.5%-38.0%).
• Results of liquid storage and cryopreservation did not correlate in individual stallions and were not related to their fertility.
• The study concluded that the response to semen preservation is difficult to predict, thus a thorough examination is needed to determine individual stallions’ suitability for semen preservation.