ABSTRACT
Nuclear transfer has been used to produce mammalian offspring in sheep, cattle, pigs, mice, rabbits, goats, cats, deer, rat, mules, and the horse. Live animals have been produced from somatic (nonreproductive) cells from adult and fetal cell lines. Recently, the authors’ laboratory reported the first successful births of an equine specie — three identical cloned mules produced from the transfer of fetal somatic cell nuclei into enucleated horse oocytes and carried full term in the reproductive tract of a female horse (mare) [1]. All of these animals developed normally and the births were unassisted; each animal is developmentally normal and healthy based on several physiological parameters monitored since birth. Subsequent to the successful birth of the first equine, Galli et al. [2] reported the birth of a single horse foal produced following the transfer of adult somatic cells into an enucleated horse oocyte. This animal was reported to be normal and healthy.
