The manipulation of gametes and embryos in farm animals.

This paper summarizes the major advances in farm animal assisted reproduction in the last 20 years with particular attention to the contributions of the authors. A main emphasis is on the biology of the oocyte, including a description of methods for isolation of developing follicles and culture of the corresponding oocytes. Milestones that have led to optimization of procedures for maturation of fully grown oocytes, fertilization, intracytoplasmic sperm injection and embryo culture in sheep, cattle, pigs and horses are described. The current status of nuclear transfer, cloning and embryonic stem cell generation and culture is also summarized for all major farm animal species. It is concluded that the manipulation of early development in farm animals is of crucial importance for agricultural purposes and that reproductive biotechnologies in farm animals are expected to play an increasing role in the next decades due to the growing demand for agricultural products from the emerging economies worldwide. In the biomedical field large animals represent increasingly important research models especially in the stem cell field for creating genetically modified animals for specific purposes. Finally, the successful translation of large animal research in the applied context requires solid science, long-term resource commitment from involved institutions, and vision, dedication and entrepreneurial skills from the scientists involved.