So is the government’s decision to let farmers shoot badgers scientifically sound? No, says John Krebs, a zoologist, member of the House of Lords, and principal of Jesus College at the University of Oxford, who recommended running the 9-year study. “They went against the science on political grounds.”
Yes, counters David King, a chemist and director of the Smith School of Enterprise and the Environment, also at Oxford. “The government’s got it right,” he says. When King was the former Labor government’s chief scientific adviser in the 1990s he supported culling, and commissioned a separate study that ended up endorsing it. The schism reveals an uneasy truth about the badger issue: science doesn’t give a clear answer about what to do.
Here are the facts. For more than a decade, bovine TB has been on the rise in Britain (see ‘Bovine burden’). To control the disease, which can spread to humans through contaminated milk, cattle are routinely screened and infected animals are destroyed. And, uncomfortable as it is for animal-lovers, killing large numbers of badgers does help to reduce levels of bovine TB.
The trial backed by Krebs (officially known as the Randomized Badger Culling Trial, or RBCT) showed a 23% reduction in bovine TB in the area of the cull, although the areas immediately outside the trial area saw an increase of roughly 25% — a consequence of badgers extending their normal range. Reviewing the data, scientists decided in 2011 that culling about 70% of the badgers in larger areas would lead to an overall reduction in bovine TB of up to 16%.
There is little disagreement among scientists about the 16% figure, says Christl Donnelly, a statistician at Imperial College London, who has devoted years to analyzing the RBCT data. But there is plenty of debate about whether that’s enough to justify a kill. Sixteen per cent “doesn’t sound terribly meaningful to me”, says Jack Reedy, spokesman for the Badger Trust, a non-profit organization based in East Grinstead, UK, that opposes the killing of badgers. He adds that controlling cattle movements and increasing TB screening on farms would have a greater impact. Adam Quinney, a beef farmer and vice-president of the National Farmers Union in Stoneleigh, which is lobbying for the cull, disagrees. “If I said to you, ‘I’m going to give you an increase in income of 16%,’ would you say that was significant?”
In July 2011, the Department for Environment, Food and Rural Affairs (DEFRA) laid out a plan for bovine TB eradication in England. The plan included increased surveillance and security measures on farms, as well as what the government described as a “science-led policy” of killing badgers in areas of high bovine TB. The plan reflects the reality that “this little micro-organism is really getting the better of us”, says Ian Boyd, DEFRA’s chief scientific adviser, who supports the cull. Politicians do not expect that the cull alone will eradicate bovine TB, but they hope that it will at least help to stabilize infection rates. Boyd insists that the new policy is rooted in the science of the RBCT.