BOZEMAN, Mont. (AP) - The Montana Farm Bureau has dropped out of a lawsuit that seeks to block bison from roaming outside Yellowstone National Park. At the group's request, the Montana Supreme Court dismissed the bureau from the case on Wednesday. The move leaves Park County as the only plaintiff in the 2011 lawsuit, which seeks to keep bison out of the 70,000-acre Gardiner Basin. The plaintiffs argue that bison outside the park pose a public safety threat and could spread disease to livestock. A pending appeal in the case challenges a January ruling by District Judge E. Wayne Phillips, who sided with state officials who lifted restrictions on bison movements that had been in place for decades. Farm Bureau vice president Jake Cummins says the group dropped out of the appeal after state officials assured it that livestock industry interests would be protected in the Yellowstone area. He said attempts to reach a settlement in the case fell short.