The shooting has finally begun in the badger cull pilot areas after years of bitter argument.
We don’t know exactly where the cull has begun or the names of the contractors pulling the triggers – there’s a virtual information blackout thanks to the threat of disruption from protesters.
That’s not all we don’t know. Critics say the government has decided to plough ahead with pilot culls in Somerset and Gloucestershire despite a long list of gaps in our scientific knowledge.
On the other hand, the numbers of cattle being slaughtered due to bovine tuberculosis have rocketed over the last decade, and it’s widely accepted that badgers are a major source of infection.
With claim and counter-claim flying around like buckshot, let’s try to separate fact from fiction.
Do badgers actually pass TB to cattle?
It seems unbelievable but we still don’t actually know for sure if badgers pass the disease to cattle, or if it’s the other way around. If badgers do infect cows, we don’t know how it happens.
But the Independent Scientific Group (ISG) on Cattle TB, which spent nearly a decade carrying out experimental badger culls and collecting data, concluded that “badgers contribute significantly to the disease in cattle”.
ISG member Christl Donnelly has found “close positive relationships” between TB in cattle herds and badgers carrying the disease. Last year she estimated that around 50 per cent of bovine TB incidents recorded in the study could be attributed to infectious badgers.
How many badgers have TB?
Estimates range from 15 per cent for the general population, based on analysis of a random sample of badgers found dead on the roads, to 30-40 per cent of animals in TB “hot-spot” areas.
There’s no way shooters can know from looking at a badger whether it has TB or not, so the likelihood is that most animals who are killed in the cull will be healthy.
Is the rising badger population to blame for the bovine TB crisis?
First, we don’t know whether the badger population really has risen, although this is frequently cited as the reason for recent rises in bovine TB.
The last survey was done in the 1990s and estimated the UK population at around 300,000 animals. A survey done in the ’80s had put the badger population at around 250,000.
But Defra, the government department running the cull, says the surveys are not directly comparable and an anecdotal rise in badger numbers “is not known for certain”.
Second, outbreaks of bovine TB went up dramatically in 2001 and 2002, which some have interpreted as the effect of an influx of untested cattle arriving in the country as farmers restocked their herds after the foot and mouth epidemic. It may have nothing to do with badgers.
Will a cull work?
This is where the experts are most sharply divided. While the ISG’s big 10-year badger study concluded that badgers were probably partly to blame for TB in cattle, it stated unequivocally that: “Badger culling can make no meaningful contribution to cattle TB control in Britain.
“Indeed, some policies under consideration are likely to make matters worse rather than better.”
Since then, other scientists have disagreed with the policy advice, but there’s little dispute about the science.
Essentially, the scientists found that if you trap or shoot badgers in a certain area, it pushes them into neighbouring areas (“perturbation”). So TB rates go down in a hot spot only to increase outside the culling zone.
The ISG results suggest that four years of intensive culling could cut bovine TB by 12 to 16 per cent after nine years.
No-one is really questioning these numbers – the argument is about whether they amount to a good result or not. Professor Sir John Krebs, who led the research, calls it a “modest” reduction and doubts whether it would be value for money.
The Environment Secretary, Owen Paterson, says: “We have to use every tool in the box because TB is so difficult to eradicate and it is spreading rapidly.”
Will a vaccine work?
Equally, there are doubts about whether vaccinating badgers will solve the problem in a more humane way. There is a dearth of evidence about whether vaccinating badgers will cut TB in cattle.
Trapping and vaccinating large numbers of badgers would be hugely expensive and time-consuming, and it could take years for the effects to be felt.
Nevertheless many wildlife groups – and the Welsh government – are vaccinating badgers now. It’s interesting that the scientist who came up with the “50 per cent of TB cases are caused by badgers” figure talks about vaccination, not culling, as the potential solution.
Are those the only options?
No. If badgers really are the problem, keeping them out of farms may be the answer. Some dairy farmers have claimed to maintain completely TB-free herds for decades using “biosecurity” measures like badger-proofing cattle troughs.
Do people really not care?
That is the claim from the government and the National Farmers’ Union – who seem to speak with one voice on this issue.
Today Mr Paterson quoted a survey carried out by YouGov which found that while 34 per cent of people oppose a badger cull, 29 per cent support it, 22 per cent don’t know and 15 per cent have no strong feelings.
True, but that’s just one poll. He didn’t mention the GfK NOP survey for the BBC News website in which 63 per cent said badgers should not be culled, 31 per cent were in favour and the rest were undecided.
How many badgers have to die?
A lot. For Mr Paterson to expect the kind of 16 per cent reduction in TB recorded in the ISG study, we are talking about getting rid of 70 per cent of the badger population in the cull areas.
Ireland has achieved very significant reductions in bovine TB, but at a cost of losing more than half her badgers – perhaps 90,000 animals – since 1995, according to one study.
Should we stop at badgers?
It’s well known that other wild animals carry bovine TB as well. Why are we only culling badgers?
There doesn’t appear to be a particularly logical answer to this, although the disease is perhaps more common in badgers than other animals.
A Defra study found TB in foxes, stoats, shrews, polecats, mice, voles, squirrels and most species of deer. The prevalence of infection was low: 1 to 5 per cent.
Nevertheless, the government researchers concluded ominously: “Deer have been implicated in the transmission of bovine tuberculosis to cattle in the past and in particular localities, especially when population density is high, they could pose a significant risk…It seems prudent to consider deer as a potential, although probably localised, source of infection for cattle.”
Watch out, Bambi.
By Patrick Worrall
