Probably the main reason for their frustration was an assertion by Professor Ian Boyd, DEFRA’s chief scientific adviser, that as few as six percent of bovine TB cases in cattle may be due to direct infection by badgers. He added that badgers may be indirectly responsible for about 50% of infections in cattle.
The implication for those at the meeting was obvious: that cattle to cattle transmission was at least as important, if not more so, than badger to cattle transmission. The significance of Professor Boyd’s statement was not lost on the Badger Trust which is campaigning against any culls. The trust described Professor Boyd’s data as a “bombshell” and added: “Professor Boyd told farmers in no uncertain terms that it is cattle, not badgers, which are the cause of the spread of bovine TB. To a hostile audience, he quoted from Imperial College research which says only 5.7% of infections in cattle were as a result of direct infection from badgers.
“He also stated that bovine TB will never be completely eradicated and that more regular testing, improved TB tests and tighter movement controls were key to reducing the spread of the disease.”
In his published presentation, Professor Boyd did not say that DEFRA was going to step up badger culling. He said England’s bovine TB strategy was aiming to achieve TB free status for England by 2038 by improved epidemiology and modelling “with intervention tailored to local TB risk in cattle, badgers and other non bovines”; developing new tools such as vaccines to control bovine TB; and increasing farmer involvement with a new model of governance and funding.
With this in mind, South East Farmer decided to track down the source of the data which Professor Boyd quoted showing that just six percent of bovine TB cases in cattle may be due to direct infection by badgers. We contacted Mark Chambers, who was at the NFU meeting and is professor in veterinary bacteriology at the School of Veterinary Medicine at the University of Surrey, Guildford. He told us that the data came from Professor Christl Donnelly at Imperial College, London, who worked on the original randomised badger culling trial which investigated how bovine TB spread between cattle, badgers and other wildlife and ran between 1998 and 2006.
We emailed Professor Donnelly a number of questions and her replies are in the article which accompanies this one.
South East Farmer asks what the What the bovine TB data tells us