Methods for the production of nuclear transfer embryos, nuclear transfer embryos and animals derived therefrom are described. The method generally comprises at least the steps of: providing at least one enucleated recipient cell; providing at least one donor cell or nucleus; providing a fusion media which is substantially free of calcium; placing said at least one enculeated recipient cell and at least one donor cell or nucleus in contact with one another to form couplets; and, fusing via electrofusion in said fusion media said at least one recipient cell with at least one donor cell or nucleus to form a nuclear transfer embryo.