VIABILITY OF IN-VIVO AND IN-VITRO PRODUCED BOVINE EMBRYOS

The viability of in-vivo and in-vitro produced bovine embryos is compared. Available data indicate that in-vitro produced embryos are more susceptible to freezing and subject to a higher incidence of fetal loss following transfer. A comparison between in-vivo (sheep oviducts) and in-vitro (bovine oviduct epithelial cells) culture conditions revealed that the in-vivo condition was superior in terms of yielding embryos with higher viability following freezing and thawing. The time of first cleavage division is important for the compaction and the viability. It is yet to be established if and how growth factors and proteins are involved in the regulation of early embryonic development. Suffice it to say that specific growth factors are produced and secreted from the bovine oviduct epithelium in-vivo and that addition of certain growth factors may improve the magnitude of embryonic development in-vitro. Much attention has been devoted the in-vitro culture per se, but oocyte quality, the in-vitro maturation conditions and the in-vitro fertilization system may be equally important.