In a mare, fertilization takes place in which reproductive structure?

• A. Ovary
• B. Oviduct
• C. Uterus
• D. Cervix

Answer: (B)

Fertilization happens in the oviduct, the muscular tube that connects the ovary to the uterus. After the mare ovulates, the egg is released into the oviduct, where sperm that have traveled through the vagina, cervix, and uterus meet the egg. This union occurs in the oviduct, typically in the ampullary region. Once fertilization occurs, the resulting zygote moves into the uterus, where it will eventually implant or, in horses, the conceptus migrates within the uterus for a period. The ovary is where the egg is released, the uterus is for implantation, and the cervix serves as a passage between the vagina and uterus; none of these are the site where fertilization occurs.