Large-scale applications of cloning technologies for agriculture: an industry perspective

The present costs and efficiencies of producing cloned embryos, pregnancies and offspring using the simplified nuclear transfer techniques developed in the authors' laboratories are compared with those required for the large-scale application of such cloning technologies in cattle. The current costs in the laboratory of producing large numbers of genetically identical cloned embryos for transfer is around $15.00 per blastocyst, which is within the cost estimated to be commercially viable for cloned female dairy embryos for transfer. However, the pregnancy and calving rates from the transfer of such embryos are still well below that required for large-scale commercial application for which ongoing pregnancy rates of at least 50% per recipient will be required. The current pregnancy rate (30-40 days post-transfer) following the transfer of an average of three cloned embryos per recipient is 37%, and the calving rate 17%, representing high losses between pregnancy diagnosis and term, in the beef industry and in some dairy situations the final product (cloned bulls for natural mating) will have a much higher inherent value and different parameters will therefore apply. Recent developments in the technologies that are likely to increase the probabilities of large-scale application are discussed, including recycling nuclear transfer embryos, somatic cell cloning, new cryopreservation techniques and automated oocyte harvesting.