BLM studying wild horse population

CHEYENNE, Wyo. — The federal government is preparing to launch a new round of studies into ways to prevent wild horses and burros from overpopulating Western rangelands, including making contraceptive drugs last longer. Right now, the longest-lasting contraceptives the U.S. Bureau of Land Management uses on female wild horses, a drug called PZP, lasts no more than a year or two. The BLM darts mares with the drug in liquid form or injects it in pellet form in mares that have been rounded up. O