The present invention provides methods of producing a clone non-human mammalian nuclear transfer (NT) embryo and methods for producing a cloned non-human mammal. Embodiments of the methods include introducing doner genetic material into a metaphase I oocyte; introducing donor genetic material into a non-enucleated oocyte; introducing donor genetic material obtained from a donor cell that is a metaphase into an oocyte; introducing donor genetic material into an oocyte, and naturally activating the oocyte or the NT embryo; and introducing donor genetic material obtained from a donor cell that is at late G1 phase into anoocyte.