Abstract

The purpose of this paper is to report on the reproductive outcomes following the transfer of cloned bovine embryos produced following somatic cell nuclear transfer. All recipients received two embryos. In Expt 1 (19 recipients), donor cells were derived from a 34 day old female foetus, while adult cows were used as the genetic donors in both Expt 2 (`Lady` from Enderby Island, 38 recipients) and Expt 3 (Elizabeth, a high genetic merit Friesian, 56 recipients). Overall, embryo survival rate to term was 12%, with little affect of experiment. This compares unfavourably with the reported 30-35% survival rate to term in embryos generated using in vitro production procedures without nuclear transfer. Of all transferred embryos, 36% were competent to survive to term. Furthermore, only 36% of the recipients were competent enough to support a pregnancy to term. We conclude that actual embryo survival is lower with nuclear transfer and IVP technology because both embryo and recipient competence is compromised.

WH, McMillan

Proceedings of the New Zealand Society of Animal Production, Volume 59, , 211-215, 1999