Avaliação de fatores relativos ao embrião e preparo da receptora que podem interferir nas taxas de gestação em programas de transferência de embriões em equinos

Abstract

Embryo transfer (ET) offers various advantages, such as obtaining foals from competitive mares, producing multiple foals in a single year, reproducing mares with health issues, and aiding mares with reproductive difficulties. Synchronizing the estrous cycle between the donor mare and the recipient mare is crucial for the success of ET. Different protocols have been studied to achieve this synchronization and improve pregnancy rates. Furthermore, the quality, age, and size of embryos can also affect pregnancy and embryo loss rates. This study analyzed ET data in mares, addressing the influence of various variables on pregnancy confirmation rates in recipients. In this retrospective study, data from 346 embryo transfers in cyclic and acyclic recipient mares from different breeding farms were analyzed, with these mares undergoing various hormonal treatments. The embryos were categorized based on their quality and size, and pregnancy confirmation was assessed via transrectal ultrasonography at 14 days. The results indicated that the embryo quality had a significant impact on pregnancy confirmation rates in recipients, while other analyzed variables did not show significance. Future research is recommended to explore other variables and include a larger sample of recipients to confirm and expand upon these findings. Furthermore, additional studies can investigate the relationship between embryo quality and other reproductive outcomes, with the aim of enhancing embryo selection strategies and the success of assisted reproduction programs.