(OHE) or spay
is the complete removal of the female
reproductive tract. The ovaries, oviducts, uterine horns, and most of the body of the uterus are removed. Not only does this procedure prevent the animal from getting pregnant
but it also eliminates the twice-yearly heat
cycles. The surgery
removes the source of production of such hormones as estrogen
(primarily produced by the ovaries). These hormones are responsible for stimulating and controlling heat cycles and play a major role during pregnancy. But they also have other effects on the body and some of them are potentially harmful.