Montana cattle raisers want Yellowstone National Park's bison quarantined to restrict the cattle disease they carry, but officials say that might also require quarantining other park wildlife such as elk.

In most cases, emergency quarantines apply to all species known to be carriers of dangerous illnesses, officials said.The Montana Livestock Commission asked the U.S. Animal and Plant Health Inspection Service last month to quarantine the park's bison because some carry brucellosis, a disease that causes cattle to abort. The bison often migrate out of Yellowstone into Montana in winter, sometimes in large numbers.

Thousands of the park's elk, which also can carry brucellosis, habitually migrate into Montana in winter. Restricting them could harm the multimillion-dollar hunting and outfitting industries in states surrounding Yellowstone Park, but officials said that might be necessary to avoid any flow of disease.

"We have to look at what's feasible, what can be done and what are the risks," said Lonnie King, deputy administrator for veterinary services at the inspection service. "We know that bison are carriers, and we know elk can carry it, too."

Conservationists and National Park Service officials have condemned the quarantine idea as biologically unsound and unworkable. They say the fact that elk and other wildlife may also have to be involved only highlights the absurdity of such a plan.

Few cattle actually graze near park boundaries in the winter, and there are no documented cases of Yellowstone bison transmitting the disease to cattle. But Montana officials worry that any livestock contact with wild bison could threaten the state's brucellosis-free status, which assures the marketability of its beef.

A quarantine is the latest of a series of attempts by Montana livestock interests to halt the nation's last free-ranging bison herd from migrating to its traditional wintering grounds north of the park boundary. The Montana Legislature has authorized hunting of the bison, and in 1988 hunters killed nearly 600 as they crossed the line.

This year the plan is to let hunters kill bull bison and to have state agents and park rangers shoot female bison that stray across.

But many other wildlife species, from elk to coyotes, are known to carry brucellosis. King said he did not know how the agency would handle that.

"We're going to look at all the options, from quarantining everything to not doing it at all," he said.