Large Scale Production of Sex-Selected Embryos by In Vitro Fertilization In Cattle: A New Opportunity for Global Business

In natural reproduction, the sex ratio is approximately 50:50. In the dairy industry, only female animals (and very few male stud bulls) are productive and most male calves are slaughtered with little financial return to the farmers. This natural limitation costs the dairy industry billions of dollars around the globe. Selecting sex of offspring has long been a dream in the livestock industry. The goal of this proposal is to develop cost-effective protocols for large-scale production of female Holstein embryos by in vitro fertilization (IVF) using sorted X chromosome bearing sperm (X-sperm). In this proposal, we attempt to address several key technical problems. The first objective is to produce maximum number of sexed IVF embryos with limited resource of sorted sperm. We recognize sexed sperm suffer from lower sperm number per dose, lower motility and lower fertility. In this proposal, we will attempt to develop a less toxic fertilization medium to support prolonged fertilization-incubation time with the belief that longer sperm/oocyte interaction will result in higher fertility. We will also test our novel embryo cryopreservation method on sexed embryos so that embryos can be stored and transported anywhere in the world. Currently most freezing technologies do not work well for in vitro produced embryos.