Do female horses have orgasm's

What many people tend to forget is that an orgasm has a biological function. In the male it serves to deliver the sperm to the vault. (a widening near the cervix). In the female it it serves to keep the sperm cells close to the cervix for as long as possible. So having said that I would say yes they do and they will have it very quickly. The stallion tends to spend a short time copulating so it would suggest that the mare has adapted to maximize the chance of insemination.