Wildlife Management

Montana succeeded in eradicating brucellosis from its cattle herds in 1985, allowing Montana ranchers to ship their cattle to other states without first testing them for the disease. Cattlemen are concerned about the possibility that brucellosis, a contagious disease that can cause abortions and infertility in domestic cattle, may be spread from Yellowstone Park's free-roaming bison and elk herds to livestock grazing along the park borders, thereby jeopardizing Montana's ability to freely transport cattle across state lines. Although its policy is not to restrict the movement of the park's bison and elk, the National Park Service has, in an attempt to reduce the risk of brucellosis transmission, killed more than 10,000 bison that have wandered out of the park in recent years. This report provides information on the (1) scientific evidence that brucellosis can be transmitted from bison and elk to domestic cattle, (2) economic damage that might arise from such transmission, and (3) management alternatives for preventing or reducing the likelihood of such transmission.

GAO found that: (1) the likelihood of transmission of brucellosis from bison and elk to cattle in the wild is not clear; (2) the most recent study of Yellowstone bison showed that brucellosis was found in about 12 percent of the bison killed in the area; (3) a study of 151 Yellowstone elk showed that the organism was found in none of them; (4) the National Park Service (NPS) and Montana wildlife officials are unaware of any documented cases of brucellosis transmission from wildlife, including bison and elk, to livestock in the wild; (5) the Montana State Veterinarian estimates that the cost of testing cattle exported from Montana for brucellosis would have been $438,000 in 1989; and (6) alternatives for managing the bison-cattle controversy include establishing bison management areas outside the park to provide winter range for bison, preventing bison from migrating from the park through various methods including shooting, and attempting to eradicate the brucellosis organism, which would require trapping and testing bison, as well as slaughtering, neutering, or temporarily sterilizing them.