Application of techniques for sperm selection in fresh and frozen-thawed stallion semen.

The research focused on improving techniques for processing both chilled and frozen-thawed horse semen. Different sperm selection and preparation methods were evaluated, the best of which were used to process whole ejaculates for cold storage or cryopreservation. The semen processed via these improved methods was then used for inseminations, which resulted in comparable conception rates to routinely used procedures.

Objective and Methodology

• The primary objective of the study was to enhance the techniques used in treating chilled and thawed frozen horse semen.
• The researchers conducted a preliminary test (Experiment I) where they tried various sperm selection techniques, including Swim-up, Glass wool filtration, Glass wool Sephadex filtration, and Percoll, aiming to determine their suitability for horse spermatozoa.
• Following this experiment, two sperm preparation techniques, Glass wool Sephadex and Leucosorb, were chosen for further experimentations (Experiment II), based on their effectiveness in Experiment I.
• Complete ejaculates were then processed using these techniques, either for cooled-storage or for cryopreservation.
• In the final stage (Experiment III), the researchers used semen processed with the techniques they tested in Experiment II to determine if the pregnancy rates from such inseminations would differ from those achieved with semen processed using conventional procedures.

Findings of the experiments

• In the first experiment, using the various sperm selection techniques resulted in the loss of between 48% and 92% of spermatozoa. Regardless, these techniques increased the percentage of progressively motile sperm and reduced the percentage of sperm head abnormalities, thus enhancing the semen’s overall quality.
• In the case of Experiment II, the techniques with Leucosorb and Glass wool Sephadex enabled the filtering of larger semen volumes, improving motility, membrane integrity, and sperm viability even after storage for 48 hours at +5 degrees Celsius. However, fewer spermatozoa were recovered with these methods compared to centrifugation.
• Successful cryopreservation of stallion semen was realized without the need for centrifugation when using the Glass wool Sephadex or Leucosorb procedure to remove seminal plasma.
• Pregnancy rates resulting from inseminations with semen processed through the techniques tested in Experiment II did not vary from those obtained with semen treated via standard procedures.

Conclusion

• The study found that the use of Glass wool Sephadex and Leucosorb filtration techniques led to an improvement in semen quality and should be considered for semen processing in stallions.
• Despite enhancements in sperm selection and preparation techniques, additional research is necessary to evaluate the potential increase in the fertilization ability of horse spermatozoa separated using such methods.