Research and Field Applications of Contraceptives in White-Tailed Deer, Feral Horses, and Mountain Goats

This paper reviews our applications of long-acting implantable steroids and immunocontraceptives in selected wild ungulates. We implanted captive white-tailed deer does with levonorgestrel but did not successfully prevent conception. We also evaluated antisperm immunocontraceptives delivered remotely via biobullet. Does immunized with plasma membrane proteins isolated from deer or porcine sperm showed persistence of antisperm antibody titers for 5 months, but these titers did not cause infertility. Our research also has included applications via biobullet or antigonadotropin-releasing hormone (GnRH), antisperm, and antiporcine zona pellucida (ZP) vaccines in female horses. Although the biobullet was effective in delivering immunocontraceptives at distances of ≤ 25 m, the anti-GnRH vaccine did not significantly reduce foal production in treated mares. In separate experiments, our treatment of captive mares wit the antiporcine ZP vaccine resulted in high antibody titers and caused infertility in most mares for 2 years. Federal scientists have experimented with implanting melengestrol acetate (MA) in free-ranging, exotic mountain goats following capture by helicopter. Treated goats demonstrated lower reproductive rates than controlled goats; however, this technique was time-consuming and expensive. Practicality and feasibility are of primary importance when considering the application of contraception in wildlife management. Ideally, these contraceptives should case long-term infertility or sterility and should be remotely deliverable to improve their potential applicability in wildlife population management