Disturbing badgers 'causes new TB outbreaks' farmers warned
Farmers who wreck badger setts in an attempt to reduce bovine TB may actually exacerbate the threat posed by the disease, a study has found.
Illegally disturbing badger habitats contributes to new outbreaks of the infection in nearby herds, according to researchers at Queen's University, Belfast.
The study found that around 5% of setts in Northern Ireland show signs of human interference.
Evidence included digging indicative of badger baiting; sett entrances being blocked with soil, boulders and branches or being pumped full of slurry; setts being ploughed over or having farm debris dumped on top.
The Institute for Global Food Security at Queen's collaborated with the University of Glasgow and the Agri-Food and Biosciences Institute in the research project, which was funded by the Wellcome Trust.
The badger has long been associated with tuberculosis in cattle, though much controversy surrounds the effectiveness of culling.
Pilot culling projects in England have been branded a failure by some scientists.
The new study, published in the scientific journal Natural Scientific Reports, focused on farmers who have acted outside the law in an effort to eradicate the disease.
The researchers found the risk of bovine TB was "significantly elevated" in areas of high badger social group density and high rates of persecution through sett interference.
Dr Neil Reid, lecturer in Conservation Biology at Queen's University, said: "The relationship between badger persecution and bovine TB in cattle could either be because persecuting badgers perturbs the population stimulating spread of the disease or farmers are more likely to persecute badgers if their livestock have previously had a TB breakdown. We can't say which way round the relationship is but we can say that persecuting badgers certainly does not lower TB risk in cattle, it is illegal and may make the situation worse. Farmers should be aware of the risks incurred by disturbing badger setts."
The new study found that farm-level risk factors, including the number of cattle movements, frequency of international cattle imports, previous bovine TB history and the proximity of neighbouring farms with a bovine TB history were far more strongly associated with new outbreaks than measures of the badger population or badger persecution.
The scientists said that suggested disease control could be improved further by increased frequency and accuracy of cattle testing, development of more sensitive tests and improved farm biosecurity.