Badger Cull in England and Wales

I wrote this report as an essay for my English Higher exams. I tried to simplify the mountains of information out there on this subject and I hope I have succeeded and you will find this informative.

The media’s coverage of the badger cull is normally attached to a picture of an angry celebrity or a sad farmer- the former opposed to the cull, the latter, supportive of it. Both have been informed by scientists that their case is valid and the real facts sway heavily in their favour. How can two groups of intelligent people come to such different conclusions, particularly in the field of science? I set out to investigate this topic, setting aside the emotional issues and looking at the science of the subject. I was hoping that the answers would be, like the badgers in question, an obvious black and white.

This has become a hotly debated issue in the UK- an e-petition to the government against the cull, submitted in September 2013, had collected 303,929 signatures- a record for the largest number of people ever to sign a government e-petition. (1)

Bovine tuberculosis (bTB) is an infectious disease of cattle and one of the biggest challenges facing the cattle farming industry today, particularly in the west and south west of England. It is caused by the bacterium Mycobacterium bovis (M. bovis), which can also infect and cause TB in badgers as well as many other mammals. (2)

Bovine TB can come as a crippling financial blow to farmers. His farm in Somerset has just reopened after a 6-month lock-down triggered by one of his cows testing positive. "Until the disease has really progressed in your cows, there are no visible signs," he says, which makes it a serious problem for cattle farmers in the UK and elsewhere

“Our results indicate that while badgers contribute significantly to the disease in cattle, cattle-to-cattle transmission is also very important in high incidence areas and is the main cause of disease spread to new areas.” (3)

(4)Bovine TB can come as a crippling financial blow, says James Small. His farm in Somerset has just reopened after a 6-month lock-down triggered by one of his cows testing positive. "Until the disease has really progressed in your cows, there are no visible signs," he says, which makes it a serious problem for cattle farmers in the UK and elsewhere

This phenomenon was dubbed the "perturbation effect". Infected badgers in the cull area fled to the surrounding unculled zone, taking TB with them. So strong was the perturbation effect that the increased herd losses in the peripheral area effectively cancelled out gains within the culled area. In fact, the RBCT's 2007 conclusions suggested that just 14 herd infections would have been avoided after a sustained badger cull covering 1000 square kilometres of farmland for five years.

But continued monitoring of the same sites where the RBCT took place has changed the picture, strengthening the justification for culling after all.

Christl Donnelly at Imperial College London was a member of the team that performed the original 2007 analysis and has periodically collected data from the study region since 2006. Between 2006 and 2011 there were 28 per cent fewer TB infections there than might otherwise have been expected. What's more, the boost seen in TB levels in the unculled outer ring did not persist. In fact, between 2006 and 2011 there were 4 per cent fewer TB cases than expected within the outer ring

Armed with the new data, scientists advising the UK government concluded that culling over four years in a hypothetical area of 150 square kilometres - killing an estimated 1000 to 1500 badgers - could achieve a net reduction of herd infections of around 16 per cent within nine years. This, they calculated, equates to preventing 47 out of 292 TB herd infections that would result in a farm being locked down.

John Krebs at the University of Oxford headed the team that did the original RBCT trials. He sees problems with the new conclusions: "The pilot cull is flawed because it aims to remove 70 per cent of badgers without an accurate estimate of the starting number." Krebs and 31 other prominent scientists wrote to DEFRA this week arguing that culling would actually risk increasing cattle TB, and calling for a rethink. "Badgers are only part of the problem - about 50 per cent of new TB cases are cattle-to-cattle," says Krebs. In Ireland, though, culling badgers has had an effect. The Irish government began a culling programme there in 2002 following a trial which found that herd outbreaks of TB were between two and 25 times less likely in culled than unculled areas (Preventive Veterinary Medicine, doi.org/b33wc7).

"There's been progress in the last 10 years that wasn't seen in the previous 30, and the difference is the badger-culling programme," says James O'Keefe, a spokesman for the Irish agriculture ministry.

DEFRA is also working on a more long-term solution that all sides in the debate support - vaccinating cattle so they cannot spread TB between themselves or pick it up from badgers. "We have proof of principle it works, but not approval," says Nigel Gibbens, the chief veterinary officer at DEFRA.

There is a big hurdle to vaccination. It is illegal in Europe, because it is very difficult to distinguish vaccinated from infected animals, as both produce identical antibodies to the TB bacteria. DEFRA has developed a test that will do just that but it will be a long road proving to the European authorities that the vaccine and the test work, then persuading them to change European law to allow vaccination. (4)

(5)

Evidence from other countries with bovine TB, such as Australia and New Zealand, shows that TB in cattle cannot be controlled without also controlling the disease in wildlife that act as a reservoir for the disease.

Research in England has demonstrated that cattle and badgers transmit the disease to each other. It also showed culling badgers leads to a reduction of the disease in cattle if it is carried out over a large enough area and for a sufficient length of time.

This application of what we have learned from careful scientific experimentation includes measures to counteract some of the problems that have been highlighted by those studies. Culling will only be permitted in areas sufficiently large that the impact of any short term increased incidence of disease - from disruption to the badger population - is outweighed by the long-term benefit in the culled area. Farmers proposing to cull must also apply management measures to reduce the risk of spread of disease between badgers and cattle, and culled areas must be planned to reduce as much as possible the likelihood, or impact of, increased movement of badgers. We have made it clear that these culls alone will not solve the problem of TB in cattle. There is no single solution and they represent part of a comprehensive package of measures that the government is taking to arrest the increase in new bovine TB cases.

In high-risk areas herds are tested annually and any cattle that test positive are removed. Herds with infected cattle are tested more frequently until all the cattle that test positive have been removed. Restrictions on cattle movements have been strengthened to reduce the chance of disease spreading from cattle to cattle, and we continue to look at ways we can improve cattle TB testing.

Farmers are taking measures to stop badgers from contacting their cattle and are beginning to assess the risk of buying cattle from herds that are at high risk of being infected. While these measures are helping to slow the advance of bovine TB, without further action they alone cannot solve the problem.

The government has funded, developed and licensed an injectable badger vaccine, but it has its limitations. Badgers need to be trapped before they can be vaccinated, and the process will need to be repeated annually for many years, which makes it extremely expensive to use. The vaccine is not 100% effective in preventing TB, and is ineffective in animals that are already infected with TB and that will continue to spread disease. So current vaccines will not be as effective as culling in reducing spread of the disease from badgers to cattle. We are planning to invest a further £15.5m in vaccine development over the next four years to continue to develop both an oral vaccine for badgers, which may be cheaper and easier to use, and a vaccine for cattle. But it will be several years at least before either of these methods are available and we cannot afford to wait for them.

(6)

Britain's top animal disease scientists have launched a devastating attack on the government's "mindless" badger cull, accusing ministers of failing to tell the truth and demanding the immediate abandonment of the killings. The government's own chief scientist has refused to back the killings.

However, the scientists reject the idea of scientific support for the cull, which could wipe out 100,000 badgers.

Another signatory, Lord Robert May, a former government chief scientist and president of the Royal Society, said: "It is very clear to me that the government's policy does not make sense." He added: "I have no sympathy with the decision. They are transmuting evidence-based policy into policy-based evidence."

A Defra spokesman said: "The leading experts Defra brought together in April 2011 agreed that the evidence shows that culling done in the right way can reduce the spread of the disease to cattle, with benefits remaining for many years. The culling policy has been developed to maximise the benefits shown in previous trials, and to minimise the impact of badgers spreading disease beyond the cull area by including hard boundaries such as motorways and rivers."

But scientists say the two-page document produced by the April meeting does not support the cull. Professor Rosie Woodroffe, of the Zoological Society of London, said: "The document simply does not endorse the policy."

The scientists, whose letter is also being sent to Paterson, claim scientific opinion in the UK is overwhelmingly against the cull. "I just don't know anyone who is really informed who thinks this is a good idea," said Professor John Bourne, who led the decade-long trial.

(7) The scientist whose research is being cited by the government to justify its plan to cull badgers in England has described the scheme as "crazy".

The plan is based on the results of a nine-year trial which showed that the spread of the disease could be slowed slightly if more than 70% of badgers in an area could be eradicated. If it was less than 70% - the spread of TB to cattle might even increase. But the scientist who carried out the study has told BBC News that these pilot studies make no sense. Lord Krebs, who is one of the government's most respected scientific advisers, said that the Department for the Environment, Food and Rural Affairs (Defra), which is administering the scheme, has no way of knowing how many badgers there are in the area, so will not know when they've killed 70% of the badgers in the area. "I would go down the vaccination and biosecurity route rather than this crazy scheme that may deliver very small advantage, may deliver none. And it's very hard to see how Defra are going to collect the crucial data to assess whether it's worth going ahead with free shooting at all," he said.

(8) The most important scientific evidence comes from the Randomised Badger Culling Trial (RBCT), also known as the Krebs trial, which ran from 1998 to 2005.  It was funded by the Government and compared the effects of proactive, reactive and no culling across ten sets of sites in England. 

Lord Krebs, who designed the RBCT, concluded that that “culling is not a viable policy option”.

"First, while badgers are clearly a source of cattle TB, careful evaluation of our own and others’ data indicates 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.

"Second, weaknesses in cattle testing regimes mean that cattle themselves contribute significantly to the persistence and spread of disease in all areas where TB occurs, and in some parts of Britain are likely to be the main source of infection.  Scientific findings indicate that the rising incidence of disease can be reversed, and geographical spread contained, by the rigid application of cattle-based control measures alone."

The conclusions of the RBCT are available to download below, contained within the Final Report of the Independent Scientific Group on Cattle TB - 'Bovine TB: The scientific evidence.'

Badgers typically live in social groups of four to seven animals with defined territorial boundaries.  Culling disrupts the organisation of these social groups, increasing the risks of disease transmission as shown below.

This is known as the 'perturbation effect'.  The Independent Scientific Group on Cattle TB concluded in its final report (2007) that it was "unable to conceive of a system of culling, other than the systematic elimination, or virtual elimination, of badgers over very extensive areas, that would avoid the serious adverse consequences of perturbation".

Patterns of direct and indirect contact between cattle and badgers naturally infected with tuberculosis, Drewe et al. 2013

This study looked at how bTB might be transmitted between badgers and cattle.  It found that direct contact between badgers and cattle at pasture, often thought to be the main route of transmission, was actually very rare. 

Biosecurity

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Effectiveness of biosecurity measures in preventing badger visits to farm buildings, Judge et al. 2011

Relatively simple practical measures can reduce some of the potential for contact and disease transmission between badgers and cattle.

This study found that simple exclusion measures (sheet metal gates, fencing and feed bins) were 100% effective in preventing badger entry into farm buildings, as long as they were appropriately deployed.  Furthermore, the installation of exclusion measures also reduced the level of badger visits to the rest of the farmyard.  

Badger vaccination

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BCG vaccination reduces risk of Tuberculosis infection in vaccinated badgers and unvaccinated badger cubs, Carter et al. 2012

Vaccination of badgers with BCG appears to be beneficial in at least two ways

This paper states that:

"Vaccination of badgers with BCG appears to be beneficial in at least two ways: by directly reducing the TB burden in vaccinated individuals and by indirectly reducing the risk of unvaccinated cubs acquiring infection, most likely through a herd immunity effect on this susceptible component of the badger population.  Indirect ‘protection’ bestowed upon juveniles before they become accessible for vaccination themselves could be an important contribution to the success of vaccinating wildlife."

9. I have managed some of the highest-yielding dairy herds in the world with consistently high levels of hygiene and disease resistance. Meticulous biosecurity and sympathetic animal husbandry are the key to stamping out TB in cattle, not shooting British wildlife.

Farmers vilify badgers but TB is mainly transmitted cow to cow. So the solution to eradicating TB lies with farmers themselves who must accept responsibility for a disease that is all too easily spread back and forth within and between herds due to poor management, lax biosecurity and substandard animal care. A slow response in tackling the disease compounds the problem, which can therefore soon reach epidemic proportions. I have seen it many times with mad cow disease, foot and mouth and now bovine TB. Alas, the farming industry prefers to scapegoat badgers rather than tackling these fundamental problems.

Water troughs are a reservoir for TB because they are rarely cleaned out. It's not uncommon for trough water to be left stagnating through the winter, collecting dead birds, rodents and various bacteria, only to be drunk by cattle in the spring. Badgers also use these troughs but it's unfair to isolate badgers when the culprit is the bacteria soup itself. Making troughs badger-proof is not rocket science, but more fundamental is the adoption of better hygiene standards by the agricultural industry.

Lax biosecurity on farms is also a major factor. Cows infected with TB should be quarantined immediately, but they rarely are. Every farm should have isolation areas to separate these animals and prevent cross-infection, but they rarely do. Biosecurity is often ignored by farmers and

poorly enforced by Defra. Infected cows can be left unquarantined on farms for weeks. Before a single badger is shot, the farming industry should get its house in order.

We also need to improve cattle welfare. Farm animal stress caused by pain and suffering can reduce an animal's immunity and make it more susceptible to diseases like bovine TB. On too many farms, there are high levels of lameness, mastitis and rough animal handling. The average incidence of lameness in our national herd is a shameful 22%.

This is lazy husbandry. We have a wealth of veterinary knowledge to eradicate disease, and in countries with more advanced control measures there are very low incidences of bovine TB.

10. Bovine TB was virtually eliminated in the UK by the late 1960s without any badgers being killed, and the disease stayed at that very low level for 20 years. The NFU (but not all farmers) has called for this ineffective and cruel mass slaughter because it needs an excuse for why the incidence of bovine TB has risen since then. The NFU would rather blame badgers than admit that increasingly intensive farming practices make animals more susceptible to disease.
Richard Mountford
Development manager, Animal Aid