By MATTHEW BROWN

Associated Press

BILLINGS, Mont. (AP) -- A judge says he will not stop the slaughter of potentially hundreds of wild bison from Yellowstone National Park that had attempted to migrate into Montana.

U.S. District Judge Charles Lovell in Helena issued a 72-page ruling Monday in which he denied a request from wildlife advocates to stop the slaughter.

More than 500 bison are being held in corrals along the border of the snowed-in park after trying to leave for food at lower elevations. Park officials plan to send an undetermined number to slaughter under a federal-state agreement meant to protect Montana livestock against the reproductive disease brucellosis.

Lovell wrote that while the slaughter of bison may be "distasteful," it is a "time-honored" method of dealing with the disease.

Opponents say they will appeal the ruling.

Copyright 2011 The Associated Press.