Development and Status of Cattle Embryo Cloning in Germany

Contents: A review about experiments in bovine embryo cloning performed by different working groups in Germany is given. The procedure is shortly described and the achieved results are specified. Average enucleation rates in the experiments were 58–74%, electrofusion rates were 31 to 85%. Between 3 and 17% of the in vitro cultured embryos cleaved to transferable embryos. The first calf emerging from nuclear transfer in Germany was born in August, 1992. A clone of three identical calves was given birth in April, 1993. Four months later a calf was born, which exclusively emerged from in vitro techniques (in vitro maturation of recipient oocytes, in vitro production of blastomere donor embryo, in vitro culture of cloned embryos). Finally some future aspects of bovine embryo cloning in Germany are illustrated.