ABSTRACT
The most important consideration for embryo transfer (ET) is to synchronize the estrous cycles of the donor animal and the recipients. ET is performed as a single embryo or multiple-embryo procedure. Disease prevention is a major advantage of ET that needs to be aggressively promoted to expand international markets for livestock. When freezing and thawing embryos, external cells are exposed to the environment before internal cells. Historically the sex of an embryo has been determined by doing a biopsy of the embryo and examining the chromosomal karyotype to determine whether the X or Y sex chromosome is present. In almost all cases embryos are harvested by nonsurgically flushing them out of the reproductive tract. Glycosaminoglycans are found in secretions of the female bovine reproductive tract, follicular fluid, the intercellular matrix surrounding cumulus cells that exhibit expansion, and in the zona pellucida.
