According to a meeting held between numerous scientific experts at the Department of Environment, Food, & Rural Affairs (Defra), in order for a badger cull to be effective:
Cull rate needs be at least 70%
Occurs for min. 4 years
Encompasses min. 150 square km
Predicted net benefit after a decade?
16% decrease in bTB on average
However, is this net benefit enough to be able to control bTB? There are conflicting opinions among the public. Farmers from the National Farmers’ Union support the cull and argue this reduction in bTB is enough, whereas animal rights activists such as from the Badger Trust cite badger culling as ineffective.
One reason that badger culling is thought to be ineffective is due to the perturbation effect, which results in surrounding areas outside of the culled region to have higher incidences of bTB infection.
This diagram below shows how the perturbation effect works:
While culling in trials has been done in the past by live cage-trapping, then shooting, current government regulations now allow free shooting instead. With this policy, farmers are allowed to shoot badgers on sight. However this method of culling may result in maiming and a slow, painful death, and may also leave behind numerous orphaned badger cubs. Thus, free shooting has been called into question in terms of welfare for the badgers culled.