title: Direct freezing of cattle embryos after partial dehydration at room temperature.
abstract: A new and simple method for freezing of bovine morulae and blastocysts was developed. Embryos were predehydrated at room temperature, frozen at -30 degrees C (cooling rate = 12 degrees C/min), and plunged into liquid nitrogen. This method was compared in vitro and in vivo to the slow freezing method (0.3 degrees C/min to -30 degrees C). Predehydration of the embryos in 1.5M glycerol was achieved by sucrose solution that makes the cells osmotically shrink. After the predehydrated morulae and blastocysts were frozen and thawed, 6 .4% (33 52 ) were developed in vitro for 48h and 44.2% (23 52 ) were hatched. Development obtained with slowly frozen embryos were 70.8% (17 24 ) and 58.3% (14 24 ) respectively. After transfer to recipient heifers, 33.3% (7 21 ) of the embryos frozen according this new method developed normally into viable foetuses or calves. This was the case for 48.5% (16 33 ) of the slowly frozen embryos.
authors.affiliation: I.N.R.A. Station de Physiologie animale 78350 Jouy-en-Josas, France.
authors.forename: N
authors.initials: N
authors.lastname: Bui-Xuan-Nguyen
authors.forename: Y
authors.initials: Y
authors.lastname: Heyman
authors.forename: J P
authors.initials: JP
authors.lastname: Renard