Insemination doses: how low can we go?

The research aims to reconsider the standard insemination dose for horse breeding, questioning the near-universal adherence to using 500 x 10(6) progressively motile sperm regardless of fertility or other factors. It proposes to demonstrate the viability of reducing this amount across different breeding methods, potentially improving efficiency and cost-effectiveness for breeders.

Historical Perspective on Equine Insemination

• This study begins by offering a review of the historical practices associated with equine artificial insemination, tracing the origins of the recommended insemination doses for different semen states including fresh, cooled, and frozen.
• Over 30 years ago, based on existing research and observations, 500 x 10(6) progressively motile sperm was established as the optimal dose to achieve maximum pregnancy rates in situations where optimal breeding conditions were not present.

Current Practice and Its Limitations

• Since the establishment of the 500 x 10(6) dose, it has been universally utilized as the standard insemination dosage, irrespective of the stallion’s fertility levels or advancements in managing mares and semen extenders.
• Even insemination doses for cooled-transported and frozen-thawed semen, which display different characteristics than fresh semen, have been calculated based on this dose. This adherence to a single standard may not take into account the potential for improved efficiency with different dose levels.

Rationale for Alternative Approaches

• The research provides data from various studies which highlight the feasibility of reducing the number of sperm used for breeding mares with fresh, cooled, and frozen semen. This indicates the potential for economic benefits for breeders who can achieve the same outcomes with lower amounts of sperm.
• This potential reduction in sperm counts also includes the possibility to utilize cutting-edge deep-horn insemination techniques, suggesting that the reliance on the traditional 500 x 10(6) dose may have impeded exploration of alternative, potentially more efficient, methods.