The use of sex-sorted semen in horses.
Authors: Samper J C, Hernandez Aviles J C, Ramirez-Agamez L F, Love C C, Gonzalez-Marin C, Fleury P, Dini P, De La Fuente A, Foss R, Campos F L, Ross P J
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Sex-Sorted Semen in Equine Reproduction Equine practitioners have long awaited practical advances in sex-sorting technology comparable to those established in cattle breeding, yet differences in equine reproductive physiology and semen variability have historically limited progress. Researchers evaluated improved sex-sorting systems (SuperGen™ sorters and Ultraplus™ processing methods) by shipping cooled semen to a central facility, then assessing sperm quality post-sorting and following preservation protocols. Counter-intuitively, the refined process actually improved sperm motility, morphology, viability and DNA fragmentation metrics post-sorting, whilst fresh sex-sorted semen demonstrated comparable fertility to conventional cool-shipped semen over 24 hours, despite a minor increase in lipid peroxidation. When frozen-thawed sex-sorted sperm were used for intracytoplasmic sperm injection (ICSI), blastocyst development rates were slightly lower than conventional semen but significantly increased the proportion of embryos of the desired sex—a meaningful outcome for breeding programmes targeting specific phenotypes or addressing sex-linked conditions. For stud farms and reproduction centres equipped for assisted reproductive techniques, these advances make sex-sorting a viable option, though stallion-specific variability remains a consideration and further work on cryopreservation protocols may enhance broader clinical application.
Read the full abstract on PubMed
Practical Takeaways
- •Sex-sorted semen is now a viable option for equine breeders seeking sex-biased foal crops, with fertility comparable to conventional semen when fresh
- •ICSI with frozen-thawed sex-sorted semen is feasible and delivers the primary benefit of increased desired-sex embryos, though expect slightly lower blastocyst rates than with conventional semen
- •Shipping cooled semen to central sorting facilities is practical; ensure protocols minimize oxidative stress and DNA damage during transport and processing
Key Findings
- •Improved sex-sorting technology (SuperGen™ and Ultraplus™) enhanced sperm motility, morphology, viability, and reduced DNA fragmentation compared to previous methods
- •Fresh sex-sorted semen fertility rates were comparable to conventional cool-shipped semen over the first 24 hours post-sorting
- •Frozen-thawed sex-sorted semen used for ICSI produced consistent blastocysts at slightly lower rates than conventional semen, but achieved higher proportion of embryos of desired sex
- •Slight increase in lipid peroxidation occurred in sex-sorted sperm despite overall quality improvements