Embryo transfer is a technological method that produces more offspring from a single female than it is possible naturally. A female of superior traits serves as a donor of eggs or embryos (embryo - fetus aged seven days after fertilization), and a female animal that is less valuable serves as a recipient of embryos. This technology rapidly spreading superior donor genetics.
Embryos can be obtained in two ways.
The first is the classic embryo transfer (In Vivo method), in which a follicle-stimulating hormone (FSH) is administered to a donor, in order to mature a larger number of follicles and consequently release a larger number of oocytes. After donor insemination, the development of the embryo takes place in the donor's body for the next seven days. After this time, a non-invasive technique of uterine lavage and embryo collection is performed. The embryos thus obtained can be inserted fresh into the recipients or frozen in liquid nitrogen for later insertion. This method can be repeated every 6-8 weeks starting from the 60th day after calving. On average, 5-6 embryos can be obtained per collection, but that number is extremely individual. The success rate of embryo insertion is around 50%. Using this method, it is NOT possible to use sexed semen.
Another method of embryo transfer is In Vitro Fertilization (IVF) method. In this method, the follicle stimulating hormone (FSH) is applied to the donor, in order to mature a larger number of follicles and a larger number of oocytes. After that, a non-invasive method of collecting eggs is performed, which will be fertilized and continue its development until the seventh day in the laboratory. The embryos thus obtained can be inserted fresh into the recipients or frozen in liquid nitrogen for later insertion. This method can be repeated every 7-14 days starting from the 45th day after calving, until about the 90th day of donor pregnancy. On average, 4-5 embryos can be obtained per egg collection, but that number is highly individual. The success rate of embryo insertion is 45-50%. By applying this method, it is POSSIBLE to use sexed semen.