IN VITRO PRODUCTION OF RUMINANT EMBRYOS: RESULTS, LIMITS AND PERSPECTIVES

After artificial insemination and multiple ovulation and embryo transfer (MOET), in vitro production of embryos (IVP) represents the third generation of techniques aimed at a better control of animal reproduction. This technique involves four major steps (Figure 1): oocyte collection, oocyte in vitro maturation (IVM), in vitro fertilization (IVF) and in vitro development of the resulting embryos (IVD). These different steps are now well established in domestic ruminant species (cattle, sheep and goat) although the variability of the number and quality of the oocytes collected and the low viability of frozen – thawed in vitro produced embryos still limit the large-scale use of this promising technology. Beyond the potential use of IVP in breeding schemes, this technique is also required for the establishment of new biotechnologies such as cloning and animal transgenesis. Additionally, the knowledge of oocyte and embryo physiology acquired through IVP techniques may stimulate the further development of other techniques such as MOET.