Eradicating TB in cattle: The options
We look at the pros and cons of the various methods proposed over the years.
Culling badgers
PROS: There is evidence, from the Randomised Badger Culling Trial carried out between 1998 and 2004, that it reduces levels of TB in cattle by 12–16 per cent. Many farmers believe it is necessary.
CONS: Badgers are not the most significant factor in the persistence of TB in the UK’s cattle, and culling them has proved very expensive. It involves reducing populations of a protected mammal in ways that are not always humane. Vaccinating badgers
PROS: Addresses the issue of tuberculosis in badgers (there is not much dispute that a proportion are infected) without killing them. Potentially much cheaper and clearly more humane than culling them.
CONS: There is no evidence at present that vaccinating badgers either reduces the prevalence of the disease in badgers or has a knock-on effect on TB levels in cattle. Would it really be possible to vaccinate all badgers in hotspot areas against the disease and to keep vaccinating them?
Vaccinating cattle
PROS: It would at least partly remove the dispute over whether badgers transmit the disease to cattle, by protecting cattle from contracting the disease. Vaccinating humans against TB in the UK has been mostly successful.
CONS: At present, there is no reliable method of distinguishing between a cow that has been vaccinated against TB and one that has TB. Research published in 2010 concluded the efficacy of the
BCG vaccine in cattle was between 56 and 68 per cent. Testing cattle
PROS: Developing a better test for cattle would mean farmers would have a far clearer idea of if and when any of their cows had suffered a TB breakdown. The current skin test is simply not good enough.
CONS: The only real downside is, according to some experts, that it would reveal bTB to be even more widespread than feared, and it would cost the government millions in compensation payments. Changing the industry
PROS: Some people believe the prevalence of bTB in the UK is down to the industrial nature of the way we farm – it’s highly intensive, cattle are always in close proximity to one another and huge numbers of possibly infected cattle are moved around every year.
CONS: Farmers produce nearly 15 billion litres of high-quality milk for UK consumers, at amazingly competitive prices. Any changes would probably increase the cost of a pint.
Here, the farmer Robert Read and his vet Dick Sibley say they have controlled TB simply by making sure that what the cows eat and drink is uncontaminated, where they live is kept clean and by introducing a better testing regime. Some of their badgers have TB, but they are not being vaccinated or culled.
By improving hygiene, Gatcombe has become
TB-free without worrying about the badgers. Anne Brummer, chief executive of the Save Me Trust – the organisation set up by the
Queen guitarist Brian May
– wants to see this approach extended on a much wider basis. “If you have a herd, we can remove TB from it within 18 months to four years,” she says.
But if Gatcombe is not just a one-off, and badgers do not give TB to cattle and culling them is ineffective, then how has the science got it so wrong? Langton argues that a series of errors and 50-50 calls in the Krebs Report in 1997, the Independent Scientific Group (ISG) report of 2007 and in other papers have led to the current scientific consensus.
Langton calls it a massive miscarriage of science. “In 2016, I went back to basics on this, and it was like going into a really dark cave without a torch – it took me two days with a photocopier just to print out and bind the RBCT study reports and papers. I emerged after two years, and after speaking to about 50 other specialists, thinking, ‘There’s something very wrong here.’”
Langton says the ISG chose to base its conclusions on which herds broke down with bTB by considering only reactors that had developed visible TB lesions. If they had also included the so-called “inconclusive reactors (IRs)”, then the impact of culling would have been found to be insignificant. He has run a model on visible-lesion data and shown no significant culling effect.
“When you go through the evidence carefully, you realise that, along the way, decisions and mistakes have been made that collectively make the science on badger culling nine times more likely to be uncertain as valid,” he says. “On that basis, science says culling should stop.”
The new strategy does promise a better and more regular cattle-testing regime.
If bTB is very largely a cattle-to-cattle transmission issue, then the problem lies in the testing regime. The current so-called SICCT ‘skin’ test, even by Defra’s admission, has low sensitivity and misses infected animals. Many people believe that new developments, such as the Actiphage blood test, could revolutionise the way we deal with bTB and is our best hope for stamping it out.
While welcoming work on “nonvalidated tests” such as Actiphage, Defra cautions that there is a long way to go before it replaces SICCT and the newer ‘Gamma’ blood test. But the new strategy does promise a better and more regular cattle-testing regime. “The only sensible thing I found in the recent document was increasing annual surveillance testing to every six months in the High Risk Areas,” says Langton.
Nearly 50 years on from finding that first bTB-ridden badger, we are still arguing about how much this beloved mammal contributes to the prevalence of the disease in cattle and whether killing them is worthwhile. While progress – on badger vaccination and, to some extent, cattle testing – has been made, it has been painfully slow, and there is no guarantee that the debates, and the culling, won’t still be going on in another 50 years.