In female animals, spaying (more technically termed ovo-hysterectomy or ovariohysterectomy) involves abdominal surgery to remove the ovaries and uterus (in humans, this is called a hystero-oophorectomy). Another option is to remove only the ovaries (oophorectomy or ovariectomy), which is mainly done in cats and young dogs. Another, less commonly performed method is an "ovary-sparing spay" in which the uterus is removed but one (or both) ovaries are left. Traditional spaying (removal of uterus and ovaries) is performed commonly on household pets (such as cats and dogs) as a method of birth control. It is performed less commonly on livestock, as a method of birth control or for other reasons. In mares, these other reasons include behavior modification.