Earth Protect Blog

By Mitch Smith

© The New York Times Co.

BLACKFOOT, S.D. »

On the ice-glazed banks of the Missouri River, coyotes chewed through the hide of a buffalo that recently died from disease. In a corral up the hill, more than 20 orphaned buffalo calves crowded together in the cold with no mother to protect them. Down in the pasture, a few animals stood apart from the others, coughing violently, clouds of their breath hanging in the winter air.

Fred DuBray spent about 30 years building that herd at his ranch on the Cheyenne River Reservation in South Dakota. But since last year, his buffalo have been dying by the dozens, victims of a microscopic invader, Mycoplasma bovis, that has ravaged pastures across the Great Plains and the West.

“You have no idea what’s going to happen,” said DuBray, whose sprawling pasture is now speckled with buffalo skeletons in various stages of decay. “I really don’t even know what to do,” he added. “Everything I try to do seems to make it worse.”

Buffalo, also called American bison, were hunted to the brink of extinction by white people in the 1800s but rebounded somewhat by the late 20th century through generations of conservation work. As the national mammal of the United States and a central part of many Native American traditions, the animal carries significance far beyond its small share of the agricultural market.

Now DuBray, who over the decades has helped lead efforts to reestablish herds on Native American lands, fears the bacteria is a new threat to the future of the buffalo, North America’s largest mammal.

“It’s not just an economic enterprise,” DuBray said. “It’s a cultural relationship that I’m trying to restore as well.”

But his fight against Mycoplasma has been complicated by the scant information about the bacteria’s effect on buffalo.

There is no data about how many animals are dying, no highly effective treatment, no official guidance on what to do when an outbreak emerges. Ranchers and researchers have relied on anecdotal accounts to come to a consensus that the ongoing surge in cases is probably the worst ever, even as they disagree about whether the bacteria is likely to have dire, species-level consequences.

“There’s just a ton that we don’t know about why this is happening and, therefore, how to manage it,” said Dr. Jennifer Malmberg, a veterinary pathologist at the Wyoming State Veterinary Laboratory who has examined some of DuBray’s animals.

Mycoplasma bovis, which is common in cattle but rarely lethal for that animal, was identified in 2013 by the federal Agriculture Department as an emerging pathogen in buffalo, with reports then that it could kill 25% of adults in an infected herd. The bacteria, which can be spread between cattle and buffalo, has been a persistent problem for buffalo ranchers in the years since and has killed wild pronghorns in Wyoming.

But it was not until last month, as word spread in agricultural circles about a sudden spike in outbreaks, that federal officials made ranchers eligible for indemnity payments of 75% of the value of each buffalo killed by Mycoplasma.

“I don’t think that Mycoplasma threatens the overall species, but it is a real threat to individual herds and to the stewards of those animals,” said Dave Carter, executive director of the National Bison Association, which represents ranchers. Carter said a Mycoplasma outbreak in 2020 killed several animals in a Colorado herd that he partly owns.

 There are far fewer buffalo now than there were centuries ago, when millions roamed the Plains. But in recent decades, their numbers have rebounded, in herds aimed at conserving the species and on private ranches where the animals are raised for meat. The federal government counted more than 180,000 privately owned buffalo on more than 1,700 farms in 2017. Thousands more live in tribally owned herds and in state and national parks. Canada also has a significant buffalo population.

Still, Dr. Danielle Buttke, a veterinary public health researcher with the National Park Service who has visited DuBray’s ranch to study the deaths, said the limited buffalo gene pool, a legacy of the large-scale slaughter during westward expansion, has made it harder for the species to withstand disease outbreaks. Without urgent action, she said, Mycoplasma threatened to undo much of the painstaking conservation work that has stabilized buffalo herds.

“It’s not just the loss of individual animals,” Buttke said. “It’s a very, very different impact to a species that already suffers from genetic bottlenecking and isolation than it is in a cattle system.” She added: “These animals can’t be replaced.”

Jeff Martin, who grew up on a buffalo ranch in Wisconsin and now studies the animals at South Dakota State University, said there was a link between the growing number of cases and the warming climate, which can cause stress for buffalo, weakening their immune systems and making them more susceptible to infections. The northern Plains, where many of the outbreaks have emerged, have experienced severe drought in recent years.

The buffalo is integral to the Lakota Sioux creation story, said Richard Williams, a consultant on Native American issues who is Oglala Lakota and Cheyenne. Lakota people, who for centuries migrated across the Plains with the buffalo, and who were sustained by its meat, consider the buffalo a relative.

“We believe that the strength of our people, the strength of our relationship in the world, was tied to the well-being of buffalo,” Williams said. Seeing the animals die from disease in large numbers, he said, is painful. “This is scary. This makes us nervous. What does this mean?”

DuBray, whose livelihood comes from raising buffalo, said his business has suffered as a result of the outbreak, a hardship he expects to worsen as he spoke publicly about his experience.

It was a risk he was willing to take, he said, to help the species.

No one is certain why Mycoplasma is spreading so widely now, but the bacteria is known to spread from animal to animal, ravaging herds once it is introduced.

The ubiquity of Mycoplasma bovis in cattle makes eradicating it virtually impossible, scientists say, and the bacteria’s genetic makeup makes it difficult to target with vaccines or drugs such as penicillin. More research is needed urgently, they said. Mycoplasma bovis is not believed to pose a risk to humans or to spread through eating meat.

Quantifying Mycoplasma deaths has been a challenge. Ranchers who have outbreaks are not required to report them, and many producers fear stigma or financial hardship if they come forward. Zach Ducheneaux, administrator of the federal Farm Service Agency, said the recent decision to compensate ranchers for their losses would give them a reason to detail their losses, eventually leading to better data about the scale of the problem.

“What’s the point of sharing any of your information if the door is closed in your face?” said Ducheneaux, who previously was a tribal council member at Cheyenne River when DuBray was helping to manage the tribal herd. “Now that we’ve opened it, I think we can have a freer communication with the buffalo industry about what their numbers are like, what their issues are like.”

Many of the known cases have emerged in privately managed herds, but federal officials said an outbreak in the fall at Tallgrass Prairie National Preserve in Kansas killed about 22 animals, around one-quarter of that herd. No other National Park Service herds are known to have had outbreaks, officials said.