Wildlife officials say more than 550 Yellowstone National Park bison have been removed so far this winter in the annual program to limit the herd size.

The Bozeman Daily Chronicle reported Sunday 328 animals have been shipped to slaughter and hunters have killed 234.

Meat from slaughtered bison is distributed to Native American tribes.

The aim is to keep the park's herd at about 3,000 head. Before this season's culling began, Yellowstone biologists estimated the park had about 4,800.

This year's goal is to remove 600 to 900 bison. Biologists say removing 600 would keep the population nearly stable, and 900 would result in a more significant decrease.

Park officials say they will keep 98 bison in quarantine to check for brucellosis, a disease that can cause domestic cattle to abort.