In this paper, we will discuss the in vitro reproductive technologies that have had the greatest impact on animal breeding and highlight our contributions to their development. For this reason, it was not the aim of the paper to make an extensive review of the published literature but rather to mention the work and publications that have directly inspired our work. We apologize in advance for those citations that are not included.
At the beginning of our career in science, in the mid-1980s, the only embryo technology that was applied in practice was superovulation and embryo transfer [multiple ovulation embryo transfer (MOET)]. At that time, soon became apparent that the MOET technique had many limits and other ways could be developed for producing embryos required by the cattle industry. A seminal paper published by Staigmiller and Moor (1984) drew our attention, as it demonstrated that immature oocytes, after in vitro maturation (IVM), could be converted into viable embryos and offspring at a level of efficiency that was remarkably high. Our interest was particularly attracted to the female germ line. On the one hand, we dreamed about the possibility of exploiting the large pool of growing oocytes in the ovaries and, on the other hand, we aimed at rescuing those fully grown oocytes present in medium to large size follicles that exist throughout the reproductive lifetime of female cattle. The aim was to overcome the physiological limitation of conventional breeding, especially in the monotocycous Bos taurus, and make a better use of female gametes that were otherwise destined to wastage by atresia. In this way, the genetic impact of females of superior genotype and performance on a given population could be greatly amplified. Indeed the oocyte is the most interesting cell in biology and may play the most crucial role in successful breeding. A significant proportion of successful embryo development can be related back to the oocyte (Staigmiller and Moor 1984) and the production of large number of good quality oocytes using in vitro techniques opened a new era in embryo technologies for farm animals.
In this paper, we will review our work of the last 20 years. Efforts started with a specific interest in the oocyte and evolved into building novel approaches to embryo-related biotechnologies ranging from control of meiosis, in vitro fertilization (IVF), embryo culture, nuclear transfer, stem cells and genetic modification of large domestic animals. We always worked in an ultrashort feedback loop between fundamental research and technology application, in close contact with the end users of the technologies that we were working on.
Such contacts have served as a strong reminder that any new technology has to have application. In our circumstances, the final result was the birth of live offspring at an acceptable rate, with several different technologies and across a number of different species that included cattle, sheep, horses, pigs and buffalo.