Elk or Bison to blame for Montana’s loss of “Brucellosis free status”

On September 3rd, 2008, Montana lost its brucellosis-free status due to two cases of infected cattle.  It was a big blow since last February the U.S. Department of Agriculture declared all 50 states to be free of brucellosis — the first time that had happened in 74 years.
Montana’s livestock producers will now be required to test bulls and nonspayed females, 18 months of age or older, 30 days before interstate shipment.

Ranchers in Montana and surrounding states are taking action to prevent any further spread of brucellosis.  A brucellosis plan of action has been proposed by the Montana Department of Livestock, which includes surveillance, vaccination, traceability/animal identification, fencing/pasture management, and other measures to help the state regain its brucellosis free status. If no additional cases of brucellosis in livestock are found, the state will be able to apply for Class Free status to USDA APHIS in late May of 2009. Also, Montana needs to prove to USDA that no additional cases of brucellosis in cattle exist in the state.

Brucellosis
is an infectious disease caused by the bacteria of the genus Brucella.  
It is a devastating illness for herds as it causes cattle to spontaneously abort if pregnant.  Humans become infected by coming in contact with animals or animal products that are contaminated with these bacteria.  To prevent infection, herdsman should use rubber gloves when handling viscera of animal; all consumers should not have unpasteurized milk, cheese or ice cream.

Who’s to blame for the source of the brucellosis disease?  Livestock officials point to wild elk and bison in the area, though there has been much discussion as to whether these are the true culprits. A four-foot high, seven-mile long electric fence has been erected near Gardiner to steer bison that migrate out of Yellowstone National Park to acceptable grazing land. In terms of sheer numbers, the Yellowstone region’s 25 elk herds dwarf the three herds of bison. And unlike bison, which move in groups, elk move freely over the region’s numerous mountain ranges, often alone or in small numbers. Livestock officials say infected elk herds around Yellowstone must be culled, but hunters are pushed back saying that efforts should focus on vaccinating cattle or eradicating the disease in bison.

There is also the probability that neither of these species are the ones responsible for the infected cattle. The fact that both the 2007 and the current brucellosis detections have occurred in Corriente cattle, a breed closely associated with brucellosis, has many questioning whether cattle, and not Yellowstone wildlife, are responsible for the transmissions resulting in Montana losing its brucellosis free status.

Government authorities continue to work with local officials toward regaining its status as a state free from brucellosis.