Influence of seminal plasma on fertility of fresh and frozen-thawed stallion epididymal spermatozoa.

The research evaluates the impact seminal plasma has on the fertility of fresh and frozen-thawed stallion epididymal spermatozoa utilized in artificial insemination, with the findings indicating the seminal plasma positively affects pregnancy rates.

Study Objectives

• The primary objectives of this research were twofold. Firstly, it sought to compare pregnancy rates between fresh and frozen-thawed stallion epididymal and ejaculated sperm after conventional artificial insemination. Secondly, the study aimed to explore the effect of seminal plasma on the fertility of epididymal spermatozoa post-insemination.

Study Methodology

• For the study, twenty-one mares were randomly assigned to three stallions. These mares were inseminated over five consecutive oestrous periods using six types of sperm samples. These categories comprised fresh ejaculated, fresh epididymal sperm with or without seminal plasma exposure, and the same categories for frozen-thawed sperm.
• Pregnancy examination was undertaken 14 days post each ovulation.

Study Findings

• The pregnancy rates varied significantly among different sperm sample categories. The highest pregnancy rate was achieved with fresh epididymal sperm exposed to seminal plasma (75%), while the lowest belonged to frozen-thawed epididymal sperm without seminal plasma exposure (6.7%).
• When the data was compiled, it became evident that both fresh and frozen-thawed epididymal sperm that had been exposed to seminal plasma resulted in significantly higher pregnancy rates than those never exposed to seminal plasma.

Study Conclusion

• The study reaches the conclusion that exposure to seminal plasma improves the fertility of stallion epididymal spermatozoa, thus improving pregnancy rates. This can have significant implications in preserving the genetics of valuable stallions in case of sudden death or unforeseen injury.