Wildlife Dimension of Bison Management in Yellowstone

A radio-collared Bison in Yellowstone National Park. Radio-tagged animals are followed to determine their potential for spreading brucellosis beyond the park's boundaries

The testing of Yellowstone Park bison is an expensive and high profile endeavor necessary to safeguard the cattle in the adjacent areas. The current testing process works on two levels: serological and cultural. A serological test looks for the presence of antibodies. This may register positive even if the individual is not carrying the disease. Antibodies may be present if the animal is resistant to the disease, or has fought off the disease in the past. A cultural test seeks the presence of the live bacteria, propogated from tissue samples: blood, milk, birth products, or aborted calves. Serological tests are further suspect because an animal may test negative for the antibodies but be infected with the disease. These individuals may not be experiencing the full effects of the disease, or may not yet have developed any immune system responses. These tests are, however, much cheaper and simpler to implement. The Greater YellowSstone InterAgency Brucellosis Committee White Paper says "Killing suspect animals generally is necessary to obtain adequate samples for bacteriologic culture." Bacteriologic propogation of the disease organism can be prevented by a host of improper conditions between the acquisition of tissue and the petri dish. This effectively means that there are more diseased animals present than indicated by the tests. To further confuse things, those animals with positive bacterial test results may not be capable of transmission. Managers treat all infected females and potential and future sources of infectious material. During the harsh winter months, the bison herds move downstream away from the frigid plateau that is the National Park. At the borders, the Montana state livestock agency performs serological tests. The historical cattle brucellosis eradication techniques of test and slaughter cannot be used on the unique, critical wild population of bison. These animals are too high in profile and do not suffer from the disease in the same fashion as the livestock herds. GYIBC White Paper Document Bison and Cattle Wars: The Battle for Public Lands in Greater Yellowstone


For information on bison in Idaho

Natural History of Yellowstone

Bovidae Family

Center for Bison Studies, MSU-Bozeman