The evolution of Mycobacterium bovis and the badger culling controversy
Against Badger Culling
From the RBCT
•After the RBCT it was suggested that proactive culling led to an increase in incidences of bovine TB in cattle herds in neighbouring non-trial areas.
•Studies suggest that culling disrupts the badgers behaviour patterns and social organisation, resulting in the movement of badgers into culled areas and an increase in territorial disruptions.
•An increase in territoriality means an increase in fighting between badgers, individuals biting one another during these disputes results in an increase of bovine TB transmission.
Historical Cattle-to-Badger Transmission
•Large population sizes increase the risk of bovine TB transmission. Pre-1930s, and before the Badger Protection Act, badger population numbers were small.
• After the 1930s, increasing badger population and cattle herd sizes meant badgers were more exposed and most likely caught bovine TB from cattle at this time.
•By analysing the historical evidence one group of
scientists suggests that bovine TB wasn’t prevalent enough in wildlife reservoirs over the last 10 years to have caused the epidemic in cattle.
•Further studies are needed to truly assess the role of badgers in the spread of bovine TB within cattle.
Scotland: Bovine TB Free
•In October 2009 Scotland was officially declared free of bovine TB.
•Practices used in Scotland were cattle-based involving a stringent testing regime and strict movement controls.
Final report of the independent Scientific Group on Cattle TB
•In the ‘Final report of the Independent Scientific Group on Cattle TB’ scientists concluded that badger culling would not significantly aid the control of bovine TB in UK cattle.
•This report suggested that the incidences of bovine TB in UK cattle herds could be reduced by implementing only cattle-based control methods.
FOR Badger Culling
From the RBCT
•It is believed that incidences of bovine TB in cattle could be significantly reduced by eradicating the risk of transmission from badger-to-cattle.
•Findings from the RBCT suggest that proactive culling led to a 23% reduction of cattle TB incidence within culled areas.
•The positive effects of culling were much more long lasting (maintained for 6 years) than the negative effects (absent after 12-18 months).
•Negative effects could possibly be avoided by ensuring culling is carried out over a very large area though more scientific evidence is needed to prove this.
Vaccines vs. Culling
•The government has suggested a famer-led approach allowing farmers to control their own local wildlife reservoir through the use of vaccines and culling. Using this approach farmers rather than tax-payer will pay for the cost of control measures.
•However, it has been shown by scientific studies that while the use of vaccinations in badgers reduces the progression and severity of bovine TB infection, it is only a preventative measure and cannot cure a badger of bovine TB.
•This suggests culling is the primary measure by which we can reduce badger-to-cattle transmission.