The objective of this proposed research is to develop embryo transfer procedures in nonhuman primates for use in biomedical research. Such procedures will provide a valuable tool for the production of nonhuman primate research models, for studies of intrauterine environment, and for studies of genetic diseases. Since there are no published reports of attempts to transfer nonhuman primate embryos, initial experiments will follow procedures which have proven successful in cattle. Embryos will be collected, using surgical methods, from naturally mated female baboons during the uterine stage of preimplantation development. The embryos will be transferred to the uterine cavity of naturally synchronized baboon female recipients. If conceptions are not obtained during these initial transfer experiments, a series of diagnostic studies will be carried out using sham transfers in mated females, and transfer of rabbit embryos to nonmated female baboons in order to determine which aspects of the transfer procedure require further refinement. As problems are identified, alternate procedures will be tested. After surgical transfer methods have been successfully developed, they will be used as control procedures for development of nonsurgical methods of embryo collection and transfer.