TD Ameritrade founder Joe Ricketts’ northwestern Wyoming domestic bison herd is back in business after dealing with a transmissible disease the burly beasts likely contracted from nearby elk.
The disease, brucellosis, can be particularly burdensome and costly for stockgrowers because it triggers a quarantine process, multiple rounds of required blood tests and restrictions on moving or selling livestock, be it cattle or bison. But about a week ago, Jackson Fork Ranch manager Antonio Rivera completed that process, according to colleague Jessica Jaubert.
“We just [finished] our last round of testing,” said Jaubert, the ranch’s communications manager. “The herd was cleared.”
Only two animals in the 48-head herd were confirmed to carry the disease, she said, and those infected bison were turned over to Wyoming State Veterinarian Hallie Hasel and euthanized. Brucella bacteria did not make its way into a conspicuous sub-herd belonging to Ricketts: the white bison often in view along the Upper Hoback River Road.
A Wyoming Livestock Board press release about the cases in Sublette County caused confusion because the state agency only identified the infected animals as a “herd” without specifying the species. Media outlets understandably presumed that cattle were infected.
Hasel, the state veterinarian, said she could not provide an interview for this story because confidentiality statutes prevented her from discussing brucellosis detections where livestock producers are named. Ricketts’ ranch staff shared no reservations about Jackson Fork Ranch being identified, and they openly shared their experience.
Brucellosis can cause abortions and other reproductive problems in female bovids, part of why it’s a concern for Wyoming cattle ranchers. It’s also transmissible to humans, where it’s often called undulant fever and can be very painful.
About five years ago, Rivera and the Jackson Fork Ranch went through a similar experience with brucella making its way into the bison herd, Jaubert said.
“That was their first case ever,” she said. “Same situation. They went through the process of contacting the state veterinarian and had to quarantine the herd until they had three clear tests in a row.”
The Jackson Fork Ranch also tests its bison for brucellosis every fall. That’s required within the state’s designated surveillance area for brucellosis.
Oddly enough, there’s a connection between the commercial bison herd contracting brucellosis and a famous, record-setting mule deer migration corridor. Northern reaches of the route the mule deer travel to get to summer ranges in the Hoback River Basin pass through the Jackson Fork Ranch. The migration path’s intersection with the ranch sparked debate when Ricketts’ was pursuing an upscale resort project that he halted in 2024 because of high costs.
To accommodate the migrating mule deer, the Jackson Fork Ranch has seasonally left gates open and “a few years ago” took down some fencing, Jaubert said.
“He’s always learning and thinking about these things,” she said of Ricketts. “It was him deciding that he needed to help facilitate these migratory routes that are across his ranch.”
Elk, in turn, have been able to more easily move around the nearly 1,300-acre property that traces the Hoback River.
“Ninety-nine percent of the time the elk just migrate through and it’s not a problem,” Jaubert said. “But if they hang around and are mingling with the bison, then they immediately call Wyoming Game and Fish.”
Elk presence can trigger hazing operations, often executed on snowmobiles — and even by drone. If they linger, it increases the likelihood that they’ll pass on brucellosis.
Most elk in the basin spend their winters at the state-run Dell Creek and McNeel feedgrounds, which are part of the elk-feeding complex that has made the Greater Yellowstone Ecosystem the last remaining reservoir of brucellosis in North America. Research has found that historically the disease flowed outward from one spot: the National Elk Refuge and nearby Jackson Hole feedgrounds.
Brucellosis rates in wild Yellowstone-region bison are high, around 60%, although there’s never been a confirmed case of wild bison transmitting the disease to domestic herds. Elk, rather, are the vector. Veterinarians and disease experts have advised wildlife managers to shift their focus to elk and the feedgrounds that have elevated brucellosis rates in wild herds for generations.
Notably, the roughly 20,000 animals that gather at Wyoming feedgrounds and the National Elk Refuge now face a more pressing ailment threatening their own populations. Wildlife managers confirmed the first cases of always-lethal chronic wasting disease on elk feedgrounds in the winter of 2024-’25.
The worst-known outbreak has been documented at the Bondurant-area Dell Creek feedground, where wildlife managers are monitoring what happens to the elk herd during a winter that disease experts have remarked is an “important” harbinger of what’s to come.