Pregnancy rates and births after the direct transfers of frozen-thawed bovine IVF embryos

Viability of In‐vivo and In‐vitro Produced Bovine Embryos

“…Excellent to good quality frozenhhawed in-vivo produced embryos have a viability similar to fresh embryos (Lehn-Jensen, 1986;Callesen et al, 1992;Hasler, 1992;Leibo and Loskutoff, 1993 and many others). On the in-vitro produced embryos data are more scarce, but pregnancies have been established following transfer a limited number of embryos frozen in glycerol (Lu et al, 1988;Goto et al, 1989;Reichenbach et al, 1992b;Larsson et al, 1992;Kajihara et al, 1992;Zhang et al, 1992), in glycerollsucrose (Massip et al, 1993) and in 1,2 propandiol as cryoprotectant (Suzuki et al, 1990). Use of ethylene glycol as cryoprotectant seems to be slightly better than glycerol (Parks and Ruffing, 1992;Leibo and Loskutoff, 1993) and culture on buffalo rat liver cells for as little as 24 h prior to freezing improves the freezing resistance O/oelkel and .…”

Techniques for preservation of mammalian germ plasm

“…Initial anecdotal reports suggested that such IVMFC embryos were much more sensitive to freezing and thawing than are embryos derived by standard in vivo methods. Very recently, however, successful cryopreservation of such in v/tro-derived embryos has been reported (Jiang et al, 1991;Suzuki et al, 1991;Dobrinsky et al, 1992;Kajihara et al, 1992;Voekel et al, 1992;Yang et al, 1992;Zhang et al, 1992). Although these reports are all in abstract form, their number alone gives strong credence to the validity of these observations.…”

Successful Production of Buffalo Embryos From Vitrified Immature and Mature Oocytes in Vitro

“…Several cryopreservation methods such as conventional (slow), equilibrium rapid freezing (vitrification) and ultra rapid freezing have been used to preserve embryos and oocytes of many animal species resulting in the birth of live offspring (Kajihara et al, 1992). Vitrification which is relatively recent approach defined as physical process by which a highly concentrated solution of cryoprotectants solidifies during cooling, without formation of ice crystals (Niemann, 1991).…”