Yellowstone National Park officials are considering capturing and shooting elk infected with brucellosis-- a disease from a bacterial infection that can cause cattle to abort their calves. This would be an extension of the policy that is in effect with the bison population in the Park.Recently ranchers in Montana and Wyoming found their cattle, which graze near the Park, infected with brucellosis. The most likely culprit is an infected elk population. The Animal and Plant Health Inspection Service (APHIS) downgrades states that test positive for brucellosis, thereby impacting the cattle industry in those states.
Since 2002, the federal government has spent $19 million to physically separate livestock and wildlife. More than 6,000 bison have been killed while trying to leave Yellowstone in an effort to maintain separation between bison and cattle. In 2008 a record number of bison were killed trying to leave the Park. Gov. Brian Schweitzer (D) opposes the current policy and says it has been a failure. There are no recorded cases of brucellosis transmission between bison and cattle.
The U.S. Cattleman's Association has identified Yellowstone as the last remaining reservoir for bovine brucellosis in the nation. In an effort to eradicate the disease, which poses a threat to the brucellosis-free status of cattle herds in Montana and Wyoming, they advocate thinning bison and elk herds. Between 1,500-2,000 head of cattle need to be tested in Montana at a cost of $12-15 per head to certify they are brucellosis free.
Wildlife advocates suggest thinning wildlife populations is not the answer. Rather they point to policies that would manage wildlife and cattle interactions. They also suggest that Wyoming's policy of feeding elk herds during the winter may spread the disease because elk cluster during the feedings. Brucella exposure rates run around 14% in elk herds which cluster during feeding, as opposed to 1-2% elsewhere.
In southern Montana, state official and ranchers are collaborating to work on a plan to reduce transmission. The plan involves additional testing, monitoring and identifying new patterns of grazing to separate cattle and wildlife spatially and temporally.
3 comments:
There are a few additional players not mentioned in the mix at Yellowstone, most importantly the re-introduction of the wolves.
While this is a positive step toward improving the natural environment within Yellowstone, there have been issues between the
wolves and the elk population that cannot be ignored. The winter feedlots for the elk population seem to be the main catalyst for the spread of the elk into the cattle regions. As they are being fed in predicable locations, the wolves, who are usually up
the mountain during winter have found a food source in the park. The food sites (I've read) are a killing ground for the wolves, who hunt in small packs, often leaving the larger group for hours as they drive their prey to exhaustion. Reportedly, a few of these sites are close to cattle areas/private land; this is where the transference of the disease comes into play. The elk, driven by the wolves are forced to leave park land and into cattle territory.
The article, suggests that citizens, park officials, public officials and ranchers
have a stake in this dilemma with the winter feedlots. While I applaud the Cattleman's association for bringing science into their argument, I think that monitoring the grazing patterns during the winter may not actually be the heart of the matter!
More fodder for the cattle+bison+wolf+elk fire!
This situation reminds of what has happened in Britain regarding TB, cattle, and badgers. For over 30 years, Britain had a program to eradicate badgers because it was believed they were transmitting TB to cattle, which could ultimately be transmitted to humans. But instead of controlling the rate of TB in the badgers, it actually increased. In 2006, Rosie Woodroffe wrote a report that was published in the Proceedings of the National Academy of Sciences noting cattle were transmitting the TB to the badgers. I wonder if anyone in the scientific community has researched whether the brucellosis is being transmitted from cattle to the elk or bison.
IF brucellosis is transmitted through birth materials (placenta?) then why aren't pregnant females the only individuals being managed, either through medical monitoring, confinement, or some other control method.
i don't know whether the bison to cattle versus cattle to bison connection has been studied. you raise a good point. i'll keep my ears peeled for it.
we will certainly be studying more about grey wolves in NR571 this semester, so stay tuned on that front.
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