Chemical Fertility Control and the Management of Assateague Ponies

Kirkpatrick, Jay

Between February of 1986 and August, 1987, a study was conducted on Assateague Island: to test the feasibility of inhibiting fertility of the horse population within the boundries of the National Seashore. The objectives of this study included (1) testing the effectiveness of remotely delivered microencapsulated testosterone propionate (mTP) to stallions, and (2) testing the effectiveness of remotely delivered microencapsulated nortethisterone (mNET) to mares. The research and theoretical considerations behind this study are set forth in the original proposal to Assateague National Seashore. The study included the treatment of stallions with mTP in an attempt to lower sperm counts and decrease sperm motility, as reported previously by Kirkpatrick et aI., (1982) and Turner and Kirkpatrick (1982) and treatment of mares with mNET in an attempt to inhibit ovulation.