Birth of lambs after direct transfer of vitrified ovine embryos

The aim of this study was to investigate in vivo viability of vitrified ovine embryos after direct transfer using a laparoscope. In vivo-derived ovine morulae and blastocysts were equilibrated in 25% glycerol and 25% ethylene glycol solution, loaded into a heat-pulled straw and vitrified. Thirty-eight embryos were transferred into 19 recipients (2 embryos per recipient) and pregnancy was examined at 54-59 days after transfer. The pregnancy, implantation, lambing, and survival rates were 15.8% (3/19), 10.5% (4/38), 15.8% (3/19) and 7.9% (3/38), respectively. The result indicates that viable lambs can be produced by direct transfer of vitrified ovine embryos.