Seasonal and age effects onembryo production in domestic cats under a standardized protocol.

Abstract

INTRODUCTION: embryo production (IVP) in the domestic cat () remains highly variable owing to intrinsic reproductive traits and the absence of fully standardized protocols. METHODS: We retrospectively analysed 108 IVP replicates produced under a single protocol (2020-2024) to quantify the effects of season, donor age and methodological parameters on oocyte yield and embryo development. RESULTS: Winter proved the most favourable season for both oocyte recovery and blastocyst formation, whereas spring, despite lower initial yields, achieved the greatest post-selection oocyte retention. Donor age correlated negatively with oocyte number; however, older queens showed higher blastocyst conversion rates, suggesting that only developmentally competent oocytes persist at advanced age. DISCUSSION: These results highlight the need for rigorous donor selection and season-tailored IVP protocols to enhance embryo yield, quality and dataset reproducibility, prerequisites for deciphering embryo-maternal signalling mechanisms. Because the domestic cat serves as a valuable translational model for endangered felids, optimizing these factors will advance both feline ART and conservation breeding programs.