Large Scale Production of Sex-Selected Embryos by In Vitro Fertilization in Cattle

Embryos with predetermined sex will obviously double the female calving efficiency in dairy industry. The ultimate goal of the project is to development an efficient system for the large scale production of sex predetermined cattle embryos using several emerging technologies including sperm sorting by flow cytometry, IVF and rapid-cooling cryopreservation (vitrification) of embryos. Through Phase I studies, we developed a less toxic fertilization system to support prolonged fertilization-incubation time, increased the embryo yield per unit straw of sorted sperm and improved the embryo survival rates after cryopreservation using our novel vitrification method liquid nitrogen surface vitrification (LNSV). A 41% pregnancy rate was established from over 3,000 embryo transfers. A. We propose to develop a system to produce sexed IVF embryos with full pedigree information by using oocytes derived either from slaughterhouse ovaries with know identification or Ovum Pick Up (OPU). B. We also propose to further improve the embryo quality by developing a serum free culture system. We will focus on developing a straw vitrification method for sexed IVF embryos. As a final objective, embryo transfer field trials will be conducted in US and China (Evergen will cover the oversea cost) to test term developmental potential of these embryos.