Freezing of day 5 and 6 sheep and goat embryos of Greek breeds

A. Pampukidou, M. Avdi, R. Ivanova, T. Alifakiotis

Abstract. The aim of the present study was to investigate cryopreservation at day-5 and 6 of sheep embryos of Chios breed and goat embryos from indigenous Greek breed by the conventional one- or multi-step methods using glycerol and sucrose. Chios sheep and indigenous goats were super ovulated using FSH-P and embryos collected surgically five or six days after mating. Thirty two day-5 and 46 day-6 sheep embryos were frozen either by the one-step or multi-step method and stored in liquid nitrogen. Thirty five and 42 goat embryos were frozen by one-step or multi-step method, correspondingly. From these stock 48 sheep embryos and 56 goat embryos were thawed and transferred into 24 ewe and 28 goat recipients. None of the ewes that received one-step frozen embryos either of day-5 or day-6 lambed. From the recipients of multi-step sheep embryos 2 lambs /17%/ from day-5 and 6 lambs /50%/ from day-6 embryos were obtained. The goats that received one-step frozen embryos delivered 4 kids (25%) from day-5 and 4 kids (33%) from day-6 embryos and from multi-step goat embryos were obtained 4 kids (33%) from day-5 and 8 kids (50%) from day-6 embryos. It is concluded that day-6 multi-step frozen embryos, either of sheep or goats, produce more viable offspring after transfer in suitable recipients.