NUCLEAR TRANSPLANTATION IN CATTLE - 1ST R ESULTS IN BELGIUM

In 1987, Prather et al. have performed the first embryo cloning by nuc lear transfer in the bovine species. Since, many researchers tried to develop and to apply the technique. While the enucleation of the recip ient oocyte, the injection of the donor blastomere and the fusion proc edure are now well controlled; the maturation and the activation as th e development and freezing of the cloned embryos need to be more inves tigated. An increase in embryonic mortality is also observed after tra nsfer in a recipient cow. Nevertheless, 10% of the cloned embryos deve lop in vitro to the blastocyst stage and give pregnancies after transf er.