Mont. Code Ann. § 81-4-212

A bull found running at large on the open range or national forest reserve in violation of the provisions of 81-4-210 through 81-4-213 may be caught and castrated by any person finding the bull, provided that any purebred dairy bull found running at large may be taken up and the party holding the bull shall notify the owner in person. If the owner of the purebred bull does not take possession of the bull within 24 hours after being notified, the party holding the bull may castrate the bull.