Can bovine embryos be successfully transferred after 40 years of cryopreservation?

ABSTRACT Global advances in reproductive biotechnology have allowed for the transfer of embryos from donor females with high genetic merit to recipients using cryopreservation technique, which preserves an embryo excellent quality and viability, thereby achieving a feasible pregnancy rate. The objective this study was evaluate viability Holstein that been cryopreserved more than 40 years under glycerol freezing. were transferred recipient heifers non-surgical method. Two 17-month-old (360 kg live weights) clinically healthy reproductively active used as recipients. bovine Grade 1 thawed evaluated their morphology. Of two transfers, one achieved, resulting birth calf. Therefore, frozen liquid nitrogen cryopreservative maintained produce