A USDA study concluding that wild Yellowstone National Park bison deemed free of brucellosis could safely establish new herds across the West, including Indian reservations, without posing risk to livestock is getting mixed reviews from Montana ranchers.
The research was scheduled to be published in the Mar. 7 edition of the Journal of the American Veterinary Medical Association.
Three years of experiments conducted on quarantined Yellowstone bison by USDA animal disease specialists and a Wildlife Conservation Society scientist showed culling calves exposed to brucellosis can create a disease-free herd.
An estimated half of Yellowstone’s 4,000 bison have been exposed to brucellosis, a disease that causes pregnant cows to abort their calves. When the bison wander outside Yellowstone National Park during the winter in search of food, they can be captured or killed.
Montana ranchers fear infected straying buffalo will transmit the disease to cattle grazing near Yellowstone, which could cause Montana to lose its brucellosis-free designation and prevent cattle from being shipped out of state without testing.
A joint management plan between the state and federal government allows for hundreds of Yellowstone bison to be shipped to slaughter when harsh winter conditions drive them from the snow covered high country to lower elevations outside the park in Montana.
Jay Bodner, Montana Stockgrowers Association Natural Resource Director, told Reuters that the USDA study lessens fears of the disease, but does not eliminate them. While the study shows no persistent infection in quarantined bison, latent infections are still possible, he said.
Ranchers have management concerns, including the number of bison allowed in a given area and the difficulty of keeping them fenced, Bodner said.
Kim Baker, Treasurer and former President of the Montana Cattlemen’s Association (MCA), said the government should stick to its plan of reducing the Yellowstone bison population from 4,500 to 3,000. Regarding its endorsement of using disease-free bison to rebuild herds elsewhere, Baker said: “I don’t think it’s in the best interest of other land holders.”
The Montana livestock industry has held there is not enough feed in Yellowstone National Park for 4,500 bison. Culling the herd by capture and slaughter provides meat for Montana’s tribes, reduces the brucellosis threat and relieves grazing pressures on the park, ranchers say. Buffalo with better nutrition also are less likely to contract disease because of stronger immune systems.
“The USDA needs to take into consideration that not all lands in Montana are government-owned or stateowned,” Baker told the Western Livestock Journal. “The days of wild and freeroaming bison are gone. … If they want to put them in a wildlife refuge or on a reservation, more power to them. … It’s not in the best interest of anyone to have them running around loose.”
Living in the park during the winter “is not copacetic for the bison,” she acknowledged, noting snow can get deep, but the animals need to be cleared off leases at a set time so brucellosis does not spread to cattle.
A full environmental impact statement must be drafted before large numbers of bison are “dumped” on an area, Baker said, emphasizing a designated surveillance area so far has worked in Montana.
“They’re not sure between the elk and the bison, who gets the brucellosis first. Bison spread it a little more readily,” she said.
From the standpoint of cattle producers and the MCA, bison should be kept within the boundaries of designated areas or private reserve, Baker stressed. “We don’t need to have a whole bunch of free bison roaming throughout Montana.”
Maggie Nutter, President of the Marias River Livestock Association representing four counties near the Canadian border, noted that four of seven cases of brucellosis found in three states last year were tested in Montana cattle believed to have been infected by elk. “It’s much harder to separate elk from cattle.”
If bison are determined to be free of brucellosis after they are quarantined for three years, the same science applies to them as cattle, Nutter told WLJ. “You either believe in the science or not,” she said. “Either cattle are brucellosis-free or bison are brucellosis-free.”
Nutter said most brucellosis is spread to cattle by elk, not bison. Elk like to congregate with cattle because of human presence and attractive feed grounds. Elk behavior patterns have changed lately, possibly because of predators like cougars, wolves and bears, she observed Many bison already are shipped out of Montana to other states such as New York, Texas, Colorado and Kansas, Nutter said. Conservation groups say a better vaccine is needed for both cattle and domestic bison.
“The vaccine currently is only 60 percent effective. The transmission risk is pretty high,” she said. “The big thinking is keeping elk separated from cattle by time and space. … I’m not excited about more bison herds not contained.”— Mark Mendiola,WLJ Correspondent