John Mack, a National Park Service wildlife biologist in Yellowstone, agrees, saying there are no documented cases of bison passing brucellosis on to livestock under natural conditions. Montana officials, however, stand behind their management plan, the result of a lawsuit they brought against two federal agencies. When the Agriculture Department threatened to revoke Montana's brucellosis-free status and the Park Service did not prevent bison from leaving the park, the state sued both agencies, forcing them to jointly agree to a plan.
Even more bison will be shot if Sen. Conrad Burns, R-Mont., gets his way. A bill he introduced last year would allow the slaughter of all infected bison, even those within the park.