The decision to expand badger culling as a key plank of the UK government鈥檚 strategy to wipe out tuberculosis in cattle is disappointing and flies in the face of evidence that it won鈥檛 eradicate the disease.
This isn鈥檛 just a continuation of the previous cull, . Up to 33,000 badgers are set to be killed in parts of England over the next six weeks under licences granted to groups of farmers. Culling now covers over 8000 square kilometres of farmland.
Several countries have eradicated bovine TB, which can devastate cattle farm businesses: infected animals have to be slaughtered and movement of livestock is restricted for months or years until the herd tests clear. In the UK, however, badger populations have become infected, and can transmit the disease back to cattle. To permanently eradicate TB, policies need to clear it from the badger population as well as cattle. Killing badgers seemed like an obvious solution, until a revealed the approach鈥檚 limitations.
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The trial showed that culling led badgers to roam more widely, transmission within their own population and infecting cattle over . Efficient, well-coordinated culling has the potential to somewhat cattle TB inside large cull zones, but this comes at the cost of increased TB on adjoining land. Small, patchy or inefficient culls can worsen the problem. Neither form of culling can eradicate the disease, because both increase TB within the badger population and spread infection to new areas.
The UK government has seen no clear benefits from three years of farmer-led culling in England. Its suggest that TB in cattle isn鈥檛 significantly lower in two culled areas than in unculled comparison areas. A third site, where culling started later, seems to have experienced more cattle TB in the first year of culling than in the three preceding years.
Increasing TB
A , on a smaller dataset, suggests that culling might be reducing TB inside cull zones and increasing it on adjoining land, as in trial culls, but these results were fragile enough that its authors 鈥渋t would be unwise to use these findings to develop generalizable inferences about the effectiveness of the policy鈥�.
In a BBC interview, the government鈥檚 chief vet that the decision to expand farmer-led culling wasn鈥檛 based on evidence showing that this method had reduced cattle TB so far.
The uncertainty over benefits contrasts with the costs. The culls over 拢5 million in 2016 alone. Their scale means that the environmental impacts of removing the UK鈥檚 largest extant carnivore cannot be ignored; previous culls have been shown to double numbers and affect several other species.
Badgers also pay a cost. Concerns that shooting causes an unacceptable level of suffering to badgers led the British Veterinary Association to its support for the approach.
Badger vaccination is a alternative, which is than culling as well as having smaller impacts on the environment, badger welfare and rural communities . Yet this approach isn鈥檛 being supported or trialled in areas with a high risk of cattle TB, where it might be beneficial.
Moreover, with , focusing on better control of cattle-to-cattle spread is likely to be more successful than any form of managing badgers.
