Oocyte and Embryo Vitrification in Horses.

Vitrification has emerged as a decisive technique in assisted reproductive technology, offering superior cryopreservation outcomes for both oocytes and embryos compared with traditional slow freezing. This chapter provides a comprehensive overview of the vitrification of equine oocytes and embryos, emphasizing the influence of technical factors, including cryoprotectant selection, exposure time, temperature control, and device volume, on vitrification outcomes. Biological factors such as the oocyte maturation stage, the presence of cumulus cells, and embryo size are also explored, highlighting species-specific responses to cryodamage. Detailed protocols for oocyte and embryo vitrification and warming are presented, including media preparation, handling conditions, and critical timing steps. Additionally, storage logistics, labeling strategies, and cryo-room design to prevent sample mix-ups and ensure regulatory compliance are discussed.