Production of identical bovine offspring by nuclear transfer

The use of nuclear transfer procedures to produce large numbers of identical bovine offspring is of great potential value for the multiplication of genotypes of superior economic value. Nuclear transfer involves the separation of individual blastomeres from donor embryos, fusion of the blastomeres with enucleated oocytes and culture of the resulting embryos in the ligated oviducts of a ewe or in vitro. Nuclear transfer embryos which develop to the compact morula or blastocyst stage are either transferred to synchronous bovine recipients or used as donor embryos for a subsequent generation of nuclear transfer. Results of nuclear transfer procedures are discussed in terms of the effect of recipient oocyte age and the age and type of donor embryos. Results from the transfer of nuclear transfer embryos to synchronous bovine recipients and development to term are also reported. © 1990