HELENA, Mont. — The state Department of Livestock hazed about 110 bison into Yellowstone National Park from private land Thursday, the agency said.

"It was a clean sweep, and all of the bison that were on Horse Butte are now back in the park where they belong," said Christian Mackay, executive director of the Board of Livestock. "Enough snow had melted to be able to conduct the operation safely, and green-up was sufficient to offer adequate feed for the bison to hold."

The operation came a day after cattle ranchers went to court to compel the Livestock Department to move the animals back into the park out of concern for the state's brucellosis-free status.

Area property owners have said they didn't want the bison moved, because no cattle are grazing in the area.

"These actions underscore the arrogance of the Department of Livestock, cattle industry, and agencies carrying out the Interagency Bison Management plan," said Mike Mease, co-founder of the Buffalo Field Campaign. "There are no cattle out here and the landowners want the buffalo around, yet the government-funded cowboys act like the only private property rights that matter are those pertaining to cattle."

A federal-state agreement calls for killing or removing bison that migrate outside the park, to prevent the spread of brucellosis — a disease that can cause cows to abort their calves.

For the past three years, state officials have allowed bison to linger outside the park past a May 15 deadline outlined in the 2000 bison management agreement.

A brucellosis outbreak last year near Bridger — related to elk, not bison — put the state on the verge of losing its federal disease-free status. If another outbreak occurs before July 2009, ranchers statewide would face a costly vaccination and testing program.

There has never been a documented bison-to-cattle transmission of brucellosis.

Yellowstone has an estimated 2,100 bison following the winter removal program and natural deaths that cut the population by more than half.