Tubo-ovarian Ligation Via Colpotomy as a Method for Sterilization in Mares.

The goal of this proposal is to develop a safe, effective, and economical method for permanent sterilization of mares based upon tubo-ovarian ligation performed via a colpotomy (vaginal incision). In year one of the proposal, we will evaluate a custom-designed instrument for the application of a nylon cable tie (zip tie) to the ovarian pedicle and oviduct of mares (n = 20) to induce ovarian ischemia and tubal ligation. We anticipate that the procedure will induce ovarian necrosis and effectively ablate ovarian function; however, if the ovarian ischemia is not sufficient to disrupt ovarian function, the ligature will effectively occlude the oviduct thereby causing sterilization via tubal ligation. Effects on ovarian function will be assessed by ultrasonography of the ovary, by serial progesterone determinations and by pathologic as well as histologic evaluation of the ovary four months after the procedure. In the second year of the proposal, we will refine the technique by using a videoendoscopic approach to apply the tubo-ovarian ligature. This approach will facilitate a minimal (2 cm)