Natural and recombinant equine chorionic gonadotropins past and future in animal reproductive technology

Equine Chorionic Gonadotropin (eCG) previously named Pregnant Mare Serum Gonadotropin (PMSG) has been widely used since the 40s in animal reproduction control. It is extracted from the blood of pregnant mares between days 40 and 120 of gestation. Animal welfare organizations have voiced concerns against mares bleeding conditions. There is currently no effective substitute for the natural PMSG. In this review, we summarize the basic knowledge of the structure and biology of eCG, and the research on recombinant eCG production in the past five years.