What is neutering? Neutering is the general term used for the surgical removal of the reproductive organs in both male and female dogs. Neutering female dogs usually involves an ovariohysterectomy, also known as a “spay” operation. This involves the removal of the ovaries and the uterus. Sometimes, an ovariectomy is performed instead, which just involves the removal of the ovaries and not the uterus. Neutering male dogs is also known as castration. This involves removal of the testicles.