By Adam Vaughan Direct contact between badgers and cows is a rare eventJason Venus/Alamy The controversial culling of thousands of badgers to prevent them spreading disease to cattle risks backfiring. It turns out the animals travel much further around the countryside when culling begins, increasing the risk of transmission. The UK government has been working with farmers since 2013 to shoot badgers across England in a bid to reduce the spread of bovine tuberculosis (TB) to cattle farms. If cows get the disease, they must be slaughtered, which costs the government around millions a year in compensation. Last month, the cull was expanded. It now takes place in 43 areas across England, from Cornwall to Cheshire. Scientists have warned of unintended negative side effects from culling for years. Now, a UK team led by Cally Ham at the Zoological Society of London has found that badgers increased the area they range in by 61 per cent after culling started, increasing the risk of bovine TB reaching cattle. Advertisement “We know that direct badger to cattle contact is rare,” says Ham. “But if the badger is going in more fields, it could spread its infection further, either through defecation or urination”. Read more: Badger cull – the science behind the gamble She also discovered the badgers spent around an hour and a half less outside their setts each night after culling began, making it harder for contractors to shoot them. The reason they are less active at night may be that, with fewer badgers around, food is more plentiful and they can pull off successful hunts more quickly. Previous studies had suggested that badgers move around more in response to a cull, but these had only looked at badgers before and after the cull. In contrast, Ham and her colleagues gathered data by fitting tracking collars to 67 badgers in north Cornwall between 2013 and 2017. The study is the first to observe real-time movements of individual badgers, rather than social groups. In a statement, Robbie McDonald at the University of Exeter said “this study shows the immediacy of the response and the scale of change brought about by badger culling”. “Culling can have a positive impact on cattle,” says Ham. “But the positive impacts can be undermined by changes to badger behaviour, and what we found here is those changes happen almost immediately after culling starts.” By comparison, she says, vaccination of badgers has none of these side effects. Efforts are underway to start a large-scale vaccination programme in west Cornwall. Journal reference: Journal of Applied Ecology, DOI: 10.1111/1365-2664.13512 More on these topics: diseases agriculture
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