An independent report has concluded that the majority of bovine tuberculosis spread in high-risk areas is a result of badger-to-cattle interaction, adding to the mounting pressure on DEFRA to approve calls for a badger cull to tackle the disease.
The report, published in the Proceedings of the Royal Society, investigated the role cattle movements play in spreading the disease based on movement data for 2004.
The analysis suggests cattle movements are directly responsible for 16% of herd infections, a further 9% of breakdowns are unexplained and possibly due to unrecorded movements across several sites belonging to a single holding.
Cattle movements are therefore responsible for between one-in-four and one-in-six breakdowns. The remaining 75% is attributed to “local effects” within high-risk areas with specific reference to badgers, the main wildlife reservoir.
“High-risk spread is probably the result of cattle-to-badger bTB interaction, though there is potential for contributions from other clustered risk factors,” says the paper.
This leads the authors to suggest that the current policy is not sufficient to reduce the level of disease, but, at best, contain it. However, to stem the geographical spread of these areas the testing regime should be amended to focus more on those areas on the periphery of a high-risk area.
Badger Trust spokesman Trevor Lawson urged DEFRA secretary Hilary Benn not to be swayed by the latest report, saying more research should be devoted to the role of unrecorded movements.
“If recorded cattle movements cause 16% of known TB outbreaks, it must be the case that the millions of unrecorded cattle movements between scattered fields on the same holding are also causing outbreaks.”
However, NFU deputy president Meurig Raymond said the report provided government with clear guidance on where its priorities lie in seeking to bring the disease under control.
“We have always argued that in hotspot areas, which account for the vast majority of total TB outbreaks, the biggest cause of disease spread is infection coming from the badger population,” Mr Raymond said.
“This report confirms that, and also concludes that cattle movements are of ‘relatively low importance’ in the overall picture.
“We are, of course, prepared to consider further cattle controls, especially to prevent the spread of disease into new areas, but this report suggests that the regime already in place is providing effective protection.”