State and federal officials have captured 133 more wild bison from Yellowstone National Park for disease testing and possible slaughter.
Wednesday's capture operation brought the total number of bison being held along the park's northern border to 513.
Park officials say the impending slaughter of those animals that test positive for the disease brucellosis remains on hold because of a pending court challenge.
But with the park's Stephens Creek corrals approaching capacity, administrators are running out of options as migrating bison continue to pour into Montana in search of food at lower elevations.
Yellowstone's 3,700 bison are prized for their pure genetics, but largely prohibited from wandering into Montana out of fears they could transfer brucellosis to livestock. The disease can cause pregnant animals to miscarry.