UC Davis achieves first equine IVF with frozen sperm

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UC Davis School of Veterinary Medicine researchers recently published their success using frozen thawed sperm for in vitro fertilization (IVF) production in Theriogenology. The assisted reproductive technologies at UC Davis made this the first time this procedure was performed successfully for equine embryos. Currently, the birth of a foal has not occurred.

According to the organizational release, IVF is commonly used in many species ranging from humans to livestock but is has been historically met with little success when it comes to equine patients. However, recent advancements have demonstrated IVF embryo production, but only if a high quality, fresh sperm is used, which creates limits to its use. There is also not a lot of information for IVF equine reproduction, such as how the embryos develop and if it is differing a lot from other reproduction approaches.

Pouya Dini, DVM, PhD, DECAR, DACT, an equine reproductive specialist lead a team, including Soledad Martin-Pelaez, DVM, DACT, a PhD student, and Stuart Meyers, DVM, MS, PhD, DACT, professor emeritus, to be able to report they have successfully fertilized equine oocytes and create embryos from frozen-thawed sperm. The team analyzed the stages of embryo development an compared it to those achieved with intracytoplasmic sperm injection (ICSI).

ICIS is the current practice for in vitro production of equine embryos with a single sperm injected directly into an oocyte. The team noticed overall development rates were no different, but IVF cycles proceeded faster, and the embryos were larger. These findings suggest a more advanced developmental stage, but further research is needed to assess its potential to be fully established as a commercial tool.²

In vitro production (IVP) enables production of offspring from mares and stallions that cannot reproduce in the traditional techniques, giving them a chance for genetic advancement as well as reproductive success. Frozen-thawed sperm for IVF also present the opportunity to further expand reproductive options by potentially using stallions that are geographically distant, allowing the use of sperm from stallions that are actively competing, or there is a limitation on the amount of semen available, and potentially help save valuable genetics from deceased stallions.

“Our team is excited to advance IVP of equine embryos to overcome historical challenges,” said Dini, in the release.¹ “The ability to use frozen-thawed sperm for IVF would be a valuable addition to current equine assisted reproductive technologies and would benefit both stallion and mare owners. This collaborative effort is the first step in evaluating the expansion of future equine IVF applications in the clinic.”

There is still a need for further resource to evaluate pregnancy outcomes and foal bred through IVF embryos produced with frozen-thawed sperm. The team mat UC Davis are assessing the genomic influence of fertilization techniques on equine embryos to help gain and provide further information about the quality of IVP equine embryos, the release concluded.¹

The study was support by UC Davis Center for Equine Health.

References

1. Young A. UC Davis First to Produce Equine Embryos By In Vitro Fertilization with Frozen Sperm. UC Davis School of Veterinary Medicine. Published November 7, 2024. Accessed November 11, 2024. https://www.vetmed.ucdavis.edu/news/uc-davis-first-produce-equine-embryos-vitro-fertilization-frozen-sperm
2. Martin-Pelaez S, Fuente A, Takahashi K, et al. IVF with frozen-thawed sperm after prolonged capacitation yields comparable results to ICSI in horses: A morphokinetics study. Theriogenology. Published online November 1, 2024. doi:10.1016/j.theriogenology.2024.10.032