Cattle ranchers in the vicinity of Yellowstone National Park lost their bid to have wild bison inoculated with vaccinated "biobullets." The National Park Service, which administers the park, rejected the proposal due to concerns about the effectiveness and impact of the vaccination.
Yellowstone is home to the last purebred herd of bison in the country, as herds elsewhere in the country have crossbred with domestic bison. There are roughly 4,600 wild bison in the park.
Roughly half of the wild bison are estimated to be infected with brucellosis, a bacterium that increases the chance of miscarriage. The ranchers are concerned that the wild animals could transmit the disease to domestic herds. The ranchers proposed the use of air rifles to shoot the bison with biobullets, which deliver a payload of vaccine. Yellowstone spokesperson Al Nash told Reuters that there have been no documented cases of a wild bison spreading disease to cattle.
In an environmental impact statement, the National Park Service concluded that "the implementation of remote vaccination at this time would not substantially suppress brucellosis in Yellowstone bison and could have unintended adverse effects to the bison population." The statement says that shooting the bison may result in injuries and change the animals' behavior. The vaccination process might further interfere with visitors' ability to view the animals.