Bovine Tuberculosis and Badgers
Summary
The Green Party SW opposes any cull of badgers in the UK, and calls for all culls, current or planned, reactive or proactive, to be discontinued immediately. This is based on current scientific understanding and legislation.
The Green Party SW recognises that bovine tuberculosis is a significant problem in South West England. The Green Party SW calls on the national government to fund and promote further scientific research into the causes and methods of transmission of bTB within and between herds; to improve biosecurity; to implement and monitor more intensive bTB testing and movement controls; and to fund research into bacteriophages and therapeutic bovine vaccines. The Green Party SW also calls on the government to legislate on improved cattle management practice, and to promote a more sustainable and ethical attitude to food production in general.
The Green Party SW denounces DEFRA's current public consultation on badger culling as disingenuous, in its attempt to manipulate public opinion into supporting policies that have already been found to be scientifically unjustified by experts. The Green Party SW calls on members to take immediate individual and group action to prevent another governmental farce.
We quote Stephanie Hilborne, Chief Executive of The Wildlife Trusts: 'We must not allow a situation to develop where our native wildlife is sacrificed for political expediency…The priority is to control the spread of disease between cattle.'
Background
At present, there are approximately 250,000 European badgers, Meles meles, in the UK. Studies in the 1970s found badgers to be carriers of M.bovis bacteria, which led many to blame them for the significant increase in tuberculosis amongst cattle. Research into this hypothesis took place from 1998-2005. Despite badgers' legally protected status, the Randomised Badger Culling Trials, commonly known as the Krebs trials, were carried out in thirty areas of 100 sq km across the UK. Sites of 'reactive culling', culling 'in reaction' to herd breakdown in areas with particular high incidence of bTB, were compared to control sites; widespread 'proactive' culling was also compared, in which the group aimed to kill all badgers in an area. More than 11,000 badgers were killed in total.
The trials were halted two years prematurely in 2003. Reactive culling near outbreak farms saw the incidence of bTB in surrounding farms increase by 25%; and whilst proactive cull areas saw a 19% reduction in TB incidence in cattle within the culled area, bTB was found to have increased by 29% in areas surrounding the culling zones.
These figures were published in Nature in December 2005 in a paper by Professor Christl Donnelly of Imperial College, London, following complaints by Prof. John Bourne, the co-ordinator of the Krebs trials, that his group had been 'sidelined' and 'misinterpreted' since the 2003 suspension of culling. A companion paper, published in the Journal of Applied Ecology by Dr. Rosie Woodroffe of the University of California, also asserted that badger culling had the overall effect of increasing the incidence of TB in cattle. The results of these two papers were more widely disseminated in the New Scientist on 17th December 2005.
Two days earlier the Department for Environment, Food and Rural Affairs (DEFRA) launched a 12 week public consultation, in which individuals are asked numerous questions on how best to proceed with culling, following on from the initial question of whether any kind of cull is needed.
There followed much local and national media coverage of the issues, including supporting statements from the National Farmers Union, and negative reaction from national groups like the RSPCA and local groups such as Somerset Wildlife Trust, specific campaigns, such as 'Stop the Cull', and more general discussion pieces about wider wildlife management issues.
One month after the launch of DEFRA's public consultation, on 20th January 2006 the Independent Scientific Group, (the independent group set up to design and oversee the Krebs/RBCT trials) circulated a letter to stakeholders involved in the consultation with serious concerns about several of the proposals. The proposal to reinstate 100 sq km area cullings was at 'serious variance' with the ISG's findings, and would seriously worsen the bTB situation. Rather, only 'systematic and prolonged culling extending to areas of 300 sq km or more' would be needed to 'have an overall positive impact on cattle herd breakdown rates'. DEFRA had massively underestimated the scale required. The Badger Trust argues that this intervention by the ISG demonstrates that 'the best available scientific advice effectively rules out' the NFU's strategy of 'targeted culling over specific areas linked to herd incidence'.
The National Beef Association, in contrast to the NFU, had already advocated much larger scale, proactive culling, that the ISG and others argue is the only efficacious possibility. Robert Forster, the chief executive, had written in Farmers Weekly that, 'A cull must be rapid, intense and thorough over a wide area. That needs huge resources. It will need operations rooms, possible army involvement, contingency planning, and a great deal of manpower supplied by the farmer' We must be single-minded and dispassionate.'
By contrast, the SW regional director of the NFU, Anthony Gibson, wrote in Westcountry Farming, two days before the release of the ISG letter, that a large scale proactive cull would be in breach of international law under the Bern Convention as well as illegal under the 1992 Badgers Act. Against the single-minded dispassion advocated by the NBA, he worried that it would 'turn the Westcountry farmer into Public Enemy Number One in the eyes of the animal-loving British consumer'. Local newspapers and national radio discussions are already bearing out public antipathy to large-scale culls of badgers. The economic, ethical and logistical difficulties, if not impossibilities, of such a task have also been widely asserted.
Why support any kind of cull?
Badgers are known to carry the Mycobacterium bovis bacterium; badgers often live near cattle; if badgers were no longer to live near cattle, one potential transmitter of bovine TB is removed. Whilst recognising that many other species also carry M.bovis, and that a badger cull would not represent a final solution to the problem, it is a measure that could be taken to protect cattle and livelihoods, that would not necessitate significant change in practice or financial burden to individual farmers.
Economic difficulties faced by British farmers are well known, and laypeople might well put sentimentality for a Wind in the Willows favourite aside, for the sake of their neighbours and local economy. There have been recent concerns about Foot and Mouth and Avian Flu pandemics, for example, and many people are not fundamentally opposed to wildlife intervention and culling to prevent animal and human disease.
Why the Green Party SW objects to badger culls
The director of science for the RSPCA, Dr. Arthur Lindley, wrote before the publication of the two papers and the ISG letter mentioned in Background, that, 'On the basis of current science, any decision to cull badgers would be totally unacceptable to the RSPCA'. His position is not a priori anti-culling, but based on evidence. The Mammal Society is another British organisation that is broad enough to have protection of both badger and cow in its remit. Also using science as its foundation, it states in both its website position statement, and its response to DEFRA's public consultation, that there is insufficient evidence to support reactive culls ' indeed it appears to be 'counterproductive', and that 'proactive culling over large areas is not regarded as an acceptable or sustainable long-term control strategy'.
Dr. Chris Cheeseman, of the DEFRA-commissioned Independent Science Group, has written papers since the early 1980s warning of the dangers of culling because of the 'negative edge effect' of both reactive and proactive culling, and since DEFRA's consultation launch has stated that 'culling is not the way forward'should not be a policy option'. The Green Party SW has the same methodology and conclusions as these non-partisan organisations and scientists.
The Green Party SW fully recognises that bTB is a massive problem to farmers, and that badgers are some of the carriers of the bacterium that, in advanced stages of infection, could be passed on to cattle. Nevertheless, based on the evidence summarised above, the Green Party SW does not believe that reactive culling would be efficacious; in fact, it has been shown to exacerbate incidence overall. Studies on badgers have shown that any disruption on their populations increases movements, increases contact, and increases susceptibility to disease. The so called 'perturbation hypothesis' was proven in the Krebs trials ' although bTB levels did decrease in areas of culling, levels increased around the sites in both reactive and proactive methods.
With regard to the alternative measure to have very wide-scale proactive culling, there are numerous objections and difficulties, legal, logistical, financial, and ethical.
The Green Party SW believes that it would contravene the European Union's Bern Convention on the conservation of European wildlife. Only if all badgers were killed would there be a possible degree of benefit: if some survived, not only would they be weaker and more scattered (and therefore intensify the 'negative edge effect' of bTB transmission), but they would also be an unsustainable 'na've population' with less future resistance to re-infection from other badgers and other animals. Apart from the legal difficulties, there are considerable ethical difficulties in seeking the extermination of a species nationwide per se, as well as in the horrifying process of slow and agonizing deaths through gassing, snaring, and shooting. In addition, apart from the logistical difficulties of finding and killing all badgers, Dr Cheeseman and others have expressed strong doubts as to the possibility of a total cull: even if all areas of badger population were tackled, there would be 'pockets of non-compliance' where the environment for various reasons would make it impossible to achieve the aim.
In addition to badgers, many other mammals are known to be carriers of M.bovis. The Merck Veterinary Manual states, for example, that 'Pigs are particularly susceptible to M.bovis, which is usually acquired from shared grazing or ingestion of dairy product'; 'Tuberculosis due to M.bovis is an important problem in most species of farmed and wild deer.' Cats are also susceptible to M.bovis, and the bacterium has been discovered in rats and foxes in Somerset. There is also the related avian form of the bacterium, M.avium, which is pathogenic for cattle and other mammals. By logic, then, proactive culling would have extremely wide limits. The 'huge resources' required by The National Beef Association's proposal for a widescale badger cull would be even larger if extended to other species.
Even without consideration of other animals, however, the regional or national slaughter of Meles meles, of which only 1% is an active carrier of M.bovis, would be legally and morally unacceptable. The Green Party SW's opposition to proactive culling of badgers is compounded by the fact that there are alternative measures to combat the devastation of bTB, outlined below. Proactive culling is an extreme, uneconomic, unnecessary, and morally reprehensible measure.
How the Green Party SW proposes bTB in cattle should be tackled
Before outlining specific proposals, we shall draw attention briefly to the closely related human form of TB (M.tuberculosis) to help laypeople understand the basic mechanisms of the disease. Although 1 in 3 humans is estimated to carry TB bacteria, healthy humans have a strong enough immune system to isolate them and not be affected. TB only becomes active when the immune system is weakened: dead or dying tissue forms 'tubercle' lesions in the lungs, lymph nodes and other organs, infective organisms are produced, and then disseminated, usually in 'aerosals' in exhaled air. Given this form of transmission, close, overcrowded conditions have been found to be ideal for spreading human TB.
Woodroffe's paper, mentioned above, suggests that culls disrupted badger social groups, leading to increased mobility and so greater contact with cattle. Hence the initially surprising increase in infection overall. It is possible that young badgers were 'orphaned' by the cull, and being less able to fend for themselves, became weakened and so more susceptible to the bacteria becoming active. With regard to tuberculosis in cattle, then, one urgent proposal is that cattle are kept in conditions in which they are neither physically weakened, nor overcrowded. This echoes a general desire for improved animal welfare made explicit in the Green Party manifesto as a principle; in this case, it also seeks to tackle a specific problem. When cattle are strong and not in close contact, likelihood of M.bovis transmission should be reduced. Such a proposal comes mainly from anecdotal evidence of farmers who have sought to provide good conditions for their livestock, and have not been badly affected by bTB; it comes also from intuition based on our knowledge of human tuberculosis.
The Green Party SW proposes that detailed studies are funded by the government into this believed relationship; and that if a correlation is found between management practices and bTB rates, that legislation is advanced to improve welfare standards. Given proof of this correlation, the Green Party SW proposes that regulated organic cattle farming would receive greater financial subsidy as a benchmark of animal welfare and the associated decreased risk of bTB (in addition to other benefits found elsewhere in Green Party policy).
The Green Party SW welcomes the government's belated move to promote more regular bTB testing in cattle. According to a 2005 paper published by an Oxford University team in Nature, cattle movements 'substantially and consistently outweigh' all other factors in predicting outbreaks of bTB. A tighter testing regime implemented in Northern Ireland in November 2004 has already led to a 40% reduction in bTB in the province. Animal welfare minister, Ben Bradshaw, has himself told the House of Commons that 80% of bTB outbreaks are caused by cattle. Given these facts, it is of fundamental importance that disease is not spread from herd to herd, and that tests are mandatory and rigorously monitored. These tests should be conducted before any movement of cattle out of farms or markets, and not simply on a regular basis (which allows the possibility of unscrupulous or innocent selling and moving just before a prescribed test date); they should also be conducted on new herds entering a farm. It is proposed that the government, rather than individual farmers, should pay for tests, to preclude possible opposition that has already been voiced by the NFU.
Further, it is proposed that the recently developed gamma interferon assay test be increasingly used as a complement to the widely used intra-dermal skin test (SID), which fail to identify at least 20% of all infected cattle. False negative tests from the SID method have occurred in animals with poor immunity, such as cows in early stages of infection or older animals. A large proportion of cows that are pregnant or have recently calved are also non-reactive to the SID, as lactation causes immuno-suppression. It is also proposed that other rapid assay tests are further developed, which can be used independently of SID, and which have a higher degree of specificity than the gamma-interferon test.
In addition to movement testing, the Green Party SW proposes that any movement of cattle is monitored, and restricted in both distance and scope. As well as reducing chances of inter-herd bTB transmission, this policy would also be beneficial to animal welfare and climate change concerns. Emphasis should be put on restriction, rather than elimination, of movement; local cattle auctions should be strengthened, not harmed, by this policy.
As a logical complement to discussion of exports, it is also proposed that the import of cattle to farms is treated with more vigilance; and that 'biosecurity' measures commonplace in many American farms, for example, be studied and emulated in this country. Farmers should refuse to purchase animals that have not undergone reliable tests (such as Gamma Interferon); bought in cattle should be segregated as far as possible from existing cattle for the first sixty days for example, and only allowed to come into close contact with the rest after a secondary test has shown them to be TB negative.
Biosecurity is about awareness to any transmission of the bacterium. Though rare, an infected person can transmit TB to cattle: so all farm workers should be regularly tested. Similarly, it is useless to segregate one's own cattle if a neighbouring farm's animals can come into contact with any sub-herd: adequate buffer zones should maintained. Given the possibility of other mammals being carriers, fences should be erected where necessary to keep deer apart from cattle. If dogs live on or near cattle farms, they should also be regularly tested as possible carriers. It is proposed that the government promotes these specific measures and general preventative attitude, through accessible education and financial assistance and incentive.
Human TB vaccines are only 80% effective, and no fully effective animal vaccine has yet been made. Vaccinating all badgers (and other M.bovis carriers) is believed to be logistically impossible, even if such a preventative vaccine could be developed. Vaccinating cows is logistically feasible however, and could, for example, be incorporated into ear tagging procedures. This approach could still be prohibitively expensive even if the millions of pounds previously allocated to culling were redirected.
In the shorter term, and whilst bTB is still particularly prevalent, the Green Party SW proposes that the government fund research into treatment of bTB, as an additional measure to preventative welfare strategies. Phages ' i.e. viruses that attack specific bacteria ' have already been initially researched in Russia, for example. Therapeutic vaccines, whereby the immune system is stimulated to produce cells which seek out and attack established infection within cells of the body, are currently being trialled for other mycobacterial infections such as Crohn's Disease. These avenues of research could be adapted to bTB, and it is proposed that this is funded with immediate effect.
Whilst most of the measures proposed here recquire some financial input, the Green Party SW concurs with agricultural economists who argue that both proactive and reactive culling would not be cost-effective. This was also the view of the 1986 Dunnett Report. By contrast, it is contended that the preventative and curative strategies advocated here would result in long-term financial gains for both cattle farmers and the government, in the region and the country as a whole. The Green Party SW understands that many farmers are in financial difficulties, and cannot afford to erect more fences, pay for more tests, etc. Taking all these factors into account along with the importance of farming to the region and the lives of cows, badgers, and potentially many other animals, the Green Party SW believes that the measures proposed here should be subsidised by the national government.
The Green Party SW further proposes that whilst vaccine/phage research should be encouraged in tandem with widespread promotion of improved testing, movement restriction, and eclectic biosecurity measures, there should also be some test sites which act experimentally for these latter preventative strategies. Standard experimental procedure is to alter but one variable at a time, and so as to determine optimal solutions to the problem of bTB in the future, variables of husbandry and animal welfare conditions, test types, movement levels, herd segregation types, etc, should be studied in designated farms, with appropriate subsidy from the government.
Finally, the Green Party SW proposes that members act individually and collectively to prevent the inefficacious culling of a species that appears to have been scapegoated by powerful interest groups in some parts of the farming community. Based on science, law, and ethics, rather than emotion or self-interest, the Green Party SW proposes that all types of badger cull be ended.
DEFRA's consultation can be found at http://www.defra.gov.uk/corporate/consult/badgers-tbcontrols/index.htm
Chris Keppie
Stroud District Green Party
6 February 2006
The Green Party SW would like to thank the many people who helped in researching and compiling this document, in particular Anne Rix, Fiona Cresswell, Jon Hooper, and Philip Booth.
