Studies on motility and fertility of cooled stallion spermatozoa.

This research article discusses a study comparing three different semen preservation methods for horse sperm, and evaluating their effect on both sperm motility after preservation and subsequent fertility rates when used for artificial insemination. The study found that a preservation method using ultra high temperature treated skim milk, sugar, saline solution and 2% centrifuged egg yolk resulted in higher sperm motility, and higher pregnancy rates when used in a controlled artificial insemination environment, compared to two other preservation methods.

Study Methodology and Findings

• The study aimed to compare the efficacy of three different extenders used in the preservation of stallion (male horse) sperm. These extenders serve to provide necessary nutrients for the sperm, while also protecting and preserving them for use at a later time.
• The three extenders tested were:
  • Non-fat, dried skim milk-glucose (DSMG)
  • DSMG added to 2% centrifuged egg yolk
  • Ultra high temperature treated skim milk-sugar-saline solution, also added to 2% centrifuged egg yolk, known as INRA82-Y
• After 24 hours of preservation, the sperm preserved with INRA82-Y exhibited significantly higher rapid sperm motility (active movement of the sperm) and higher sperm velocity parameters than the sperm preserved with the other two extenders. This suggests that the INRA82-Y extender was more successful at maintaining sperm viability.
• The fertility trial involved the collection of semen from three stallions of the Maremmano breed. This semen was then diluted using the INRA82-Y extender and stored in a refrigerated container.
• Following this, 56 mares of the same breed were artificially inseminated with the preserved semen. The inseminations took place both in three Artificial Insemination (AI) centres and at the breeders’ facilities.
• The pregnancy rates after one cycle and across the entire breeding season were significantly higher for the mares inseminated at the AI centres (at 54.8% and 80.6%, respectively) compared to the mares inseminated at the breeders’ facilities (28% and 52%).
• The rates of successful births (foaling rates) did not significantly differ between the mares inseminated at the AI centres and those inseminated at the breeders’ facilities.

Conclusion

• Overall, the study concluded that the INRA82-Y extender resulted in higher sperm motility and higher pregnancy rates, particularly when used in the controlled environment of an AI centre. This suggests that it is a superior method for the preservation of stallion semen when compared to the two other extenders tested in the study.
• These findings could have significant implications for the equine breeding industry, potentially leading to more efficient and effective preservation methods for stallion semen and ultimately higher pregnancy rates from artificial insemination.