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Bovine TB jargon explainer

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The TB status of cattle herds – how does that work?

The Animal and Plant Health Agency (APHA) maintain in recent publications (Birch et al. 2024 and APHA epidemiology reports for 2023) that it is the number of ‘OTF-W’ herd breakdowns that is the best headline measure of the change in bovine TB herd incidence in relation to transmission caused by badgers. How credible is this claim and why do they make it? The reality is that OTF-W (Officially TB Withdrawn) and OTF-S (Officially TB Suspended) cattle herds are simply two categories of a positive disease status.



The SICCT test – and the difference between ‘reactors’ and ‘inconclusive reactors’

The most commonly used test for bovine TB in cattle currently is the tuberculin test or SICCT (Single Intradermal Comparative Cervical Tuberculin) test. It is the main test for which farmers receive financial compensation if they receive a ‘positive result’ or ‘reactor’, and cattle are slaughtered prematurely. One big limitation of the tuberculin skin test is its sensitivity. Studies suggest that skin test herd sensitivity in Great Britain averages around 80% at ‘standard interpretation’. In practical terms, this means that on average 20% of TB-infected cattle herds may be missed by one round of skin testing, at ‘standard interpretation’, and it might be more. Even at ‘severe interpretation’ (explained later), many individuals slip through the testing net.

The skin test involves the injection of two different deactivated TB proteins, bovine and avian, in the neck area of each individual animal in a herd, followed 3 days later by a check of the injection sites to measure the extent of any skin thickening reaction (lump).

The SICCT test for bovine tuberculosis (bTB) is read by comparing the size of the skin reaction to bovine tuberculin and avian tuberculin. At ‘standard interpretation’, the test is ‘positive’ when the reaction to bovine tuberculin is greater than the reaction to avian tuberculin by 4 mm or more. Where the reaction to bovine tuberculin is greater than the reaction to avian tuberculin, but by less than 4mm, the result has been considered ‘inconclusive’ (IR) and usually retested after 60 days. Where the reaction to bovine tuberculin is the same as the reaction to avian tuberculin, the test is ‘negative‘.

If the IR subsequently tests clear, it can rejoin the herd. These animals, then known as ‘resolved IRs’, are either isolated, restricted for life to the holding in which they were found, or sent for slaughter according to rules on the risk level at each location. If the second test shows a reaction (tuberculin lump is 4 mm or more than the avian tuberculin lump), individuals are classed as a ‘reactor’ and compulsorily slaughtered. Sometimes herds have to pass two tests 60 days apart after an initial ‘inconclusive‘ test to regain ‘TB Free’ status.  Animals with lumps less than 4mm may also be slaughtered as ‘direct contacts’ (DC’s), (individuals that have been in contact with known infected animals).

Research has found that the odds of a ‘resolved IR’ becoming a subsequent ‘reactor’ during study periods were seven and nine times greater than for negative testing cattle in the HRA and Edge Area of England respectively (see May et al. 2019 here). So why create such an important operational, yet subjective division between ‘reactors’ and ‘inconclusives’?

What happens to an animal that is a ‘reactor’?

An animal that is a ‘reactor’ is slaughtered and examined for signs of bTB. It must have either a ‘post-mortem examination’ (PME) undertaken either by an APHA veterinary pathologist, or in the vast majority of cases, an examination at an abattoir where meat inspectors undertake a ‘simple post-mortem meat inspection’ (PMMI). Both processes (PME & PMMI) are looking for ‘visible lesions’. These are physiological changes to organs, glands and other areas caused by the disease. Tissue samples from selected ‘positive’ animals are taken for further testing (bacteriological culture) in one of APHA’s designated diagnostic laboratories to try and grow M. bovis (the bovine TB bacilli) and then identify the specific strain of the bacterium through DNA typing or sequencing. Alternatively, M. bovis may be confirmed via PCR (Polymerase Chain Reaction) analysis. PCR is a laboratory technique for rapidly producing copies of a specific segment of DNA, which can then be studied in greater detail. Evidence of bTB infection by one of these methods results in the ‘confirmed’ status.

It is not always possible to locate ‘visible lesions’ at PMMI, and therefore culture the bacterium from infected animals. This is particularly so if ‘micro-lesions’ are present; these are too small to be detected visually and can only be identified by fine sectioning of tissues. Furthermore, although ‘visible lesions’ of bTB are usually located in the lung tissues and associated lymph nodes, their location can vary depending on the movement of infection around the animal post-primary infection. The size and number of visible lesions (if present) can also vary and are not always correlated with the length of time an animal might have been infected. 

How accurate are the abattoir checks for TB lesions – and thus how accurate is the ‘confirmed’ status?

Stating the obvious, abattoir checks are very different to laboratory checks: the proportion of abattoir checks to laboratory checks is unclear. The ‘necropsy’ (autopsy for animals) of the dead animal in an abattoir is a rapid procedure, undertaken in slaughterhouse conditions. The meat inspector doing the procedure has a limited amount of time to look for TB lesions; some have reported as little as 4 minutes per animal. In this time, they have to administer 6 major cuts to the carcass and may take samples in 3 different locations; glands, lungs, gut.   

During the conveyor belt nature of rendering, it is quite possible that the animal to whom each set of guts belong is unclear, so in the event of lesions being found, the process has to be stopped, causing delay and cost to try to clarify. In order to avoid faecal contamination of the abattoir, the guts are rarely (if ever) opened. The search for gut lesions is therefore restricted to examination of the outside of the organ only, and is it therefore more likely to miss diseased tissue here than in other locations.

If lesions are found, restrictions start to kick in. The abattoirs must temporarily slow operations and the area must be cleaned, losing working time & efficiency. Extra paperwork must be completed. It is not in the interest of any of those involved to find lesions – the schedule becomes less efficient and less profitable. It has even been suggested that ‘not spotting’ disease can sometimes be encouraged.

How do ‘confirmed reactors’ and ‘unconfirmed reactors’ relate to OTF-S and OTF-W status?

If the animal is registered as a ‘confirmed reactor’, the herd from which it came is registered as ‘OTF-W’ (withdrawn). If no lesions are found, and the checks for M. bovis bacteria are negative, the animal is registered as an ‘unconfirmed reactor’ and the herd is registered or remains as ‘OTF-S’ (suspended). A herd is also considered ‘OTF-S’ when animals are removed/separated due to a skin test finding of ‘inconclusive reactors’ and must be retested to become OTF (Officially TB Free) again.

Is there a clear difference between ‘OTF-W’ and ‘OTF-S’ using the ‘confirmed’ and ‘unconfirmed’ method of disease surveillance?

The division of ‘reactors’ into ‘confirmed’ and ‘unconfirmed’ has created an artificial and unmeasurable division of disease diagnosis and infectiousness. All ‘reactors’ have been exposed to bTB, all have some level of disease, all may be infectious. All should be treated as such. Which is why in Wales, since 01 April 2023, the SICCT test is read at ‘severe interpretation’. This means that the ‘positive’ cut-off point (difference in bump size) is lowered so that some animals previously classified as ‘inconclusive reactors’ (IRs) at the standard interpretation are now classified as full ‘reactors’. Thus Wales now regards the majority of herds with ‘reactors’ of all kinds as ‘OTF-W’ by default.

The reason bovine TB proliferates is because the OTF-S herds that clear their onward tests, but that are in reality still infected, are likely to go on to infect the herds to which they are sold, and the disease can then take years to appear in that new herd. ‘Reactors’ from the new herd may not reveal ‘visible lesions’ at PME, and then the source of disease cannot be traced back. In this situation, ‘environmental’ sources (usually badgers) have often been blamed for the ‘new’ infection.

The current system is based on the outmoded vet and farmer ‘rule of thumb’ that cattle may carry bovine TB in a manner that is low risk to other cows. This is not the case, as any that are truly in remission are always vulnerable to ‘recrudescence’ and becoming infectious, and it is an unpredictable risk. It could happen for a range of reasons such as stress, ill health or use of medication. The kind of long term ‘latency’ seen in human TB has never been demonstrated in cattle.

The result of the current testing regime is to separate positive testing animals into two clearly overlapping categories. The high specificity of the SICCT test (approximately 99.98% at standard interpretation) means that any cow that tests positive is almost certain to carry bovine TB.

So why has APHA chosen to use OTF-W as a measure of disease rather than OTF-S?

The number of OTF-W herds has been coming down in recent years as the later cases / older infections are those that are most likely to be detected by testing. DEFRA are keen to report that their bTB control policy is working, and they largely use data for OTF-W rather than OTF-S which has stayed constant or is slightly rising, to try to show this (see below & recent letter in Vet Record). This is even though common sense says that ‘all reactors’ (both conclusive and inconclusive) are positive for bovine TB, and therefore better reflect ‘new infection’ rate. So OTF-W + OTF-S would be the statistic that best shows overall disease trends. The current (September 2024) bTB Dashboard for England show the total number of New Herd Incidents (NHI’s) at 2464, of which 1042 (42%) are OTF-W, and the higher 1422 (58%) are OTF-S.



And also…

The results of the Randomised Badger Culling Trial (RBCT) are the basis for the government badger cull policy. The RBCT is the science that DEFRA has used to create policy, and in court to defend their decisions to experiment with badger culling from 2013. The RBCT claimed that proactive badger culling can significantly reduce bovine TB in cattle within cull areas; very many subsequent studies are heavily derived from it. The RBCT claimed a 19% benefit from badger culling from analyses that used only OTF-W data. However, when OTF-S + OTF-W data were used, all analyses agreed that there was no measured benefit from badger culling. Badger culling did not have any effect at all. 

It is not difficult to see where the oversights have been and are still being made. How is it possible that basic scientific and veterinary evidence is being so badly misrepresented? It is clear that the distraction caused by the claim that badger culling will deliver significant disease benefit has been disastrous. Published science shows that it hasn’t worked (here) and that it was never going to work (here and here). So why don’t DEFRA urgently do something about it?

Bovine TB roundup 2024

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Everything changes but stays the same?

2024 has been a remarkable year, where it seems that better awareness of the bovine TB scandal is emerging. Yet institutional forces struggle to grapple with poor science, the embarrassment of failing policy and the need for decisive steps to overcome decades of oversight, dogma and vested interest.

In February, DEFRA’s Animal and Plant Agency (APHA) published a controversial paper (Birch et al.) in Scientific Reports that the DEFRA Minister Steve Barclay trumpeted immediately as showing that badger culling since 2013 was ‘working’ (see here). The journal  and the authors refused to change a misleading abstract that implied this, despite the paper stating twice (on careful reading) that the observed overall reduction in bovine TB over the study period could not be attributed to badger culling. All disease measures implemented, including more frequent cattle testing, were analysed together with no control. Basically the analysis is just a time period study, as pointed out in Prof David Macdonald’s earlier comments on the draft paper (see here) for work already labelled as policy-led science (see here).

DEFRA’s tactics appeared to be to try to justify badger culling in order to reverse the ‘phasing out’ of badger culling by the 2020 ‘Next Steps’ policy. This was perhaps also addressing the High Court’s expectation, stated 5 years previously, that policy should ‘adapt and learn’ from the results of Supplementary Badger Culling. The DEFRA plan, as revealed on 14th March, was to introduce something called ‘targeted culling‘ (see here), which was in reality a rebranding of epidemiological culling as carried out in the Low Risk Area (‘LRA Culling’) of England since 2018, including in Cumbria, south of Penrith. In this and a further cull area in Lincolnshire, culling of 100% of badgers in a core area and beyond was permitted over three or more years, with some badger vaccination afterwards.  DEFRA refused to comment on a detailed report (here) documenting its epidemiological failings and its continuing clumsy approach to investigating sources of infection. Even now new breakdowns are happening in the Cumbria Area 32 due to unwise cattle trading and persistent infection.

The March 2024 DEFRA plan was to allow extensive culling into the future across England at the discretion of the Chief Veterinary Officer, potentially under a general licence, further negating provisions of the Protection of Badgers Act 1992. It looked like Defra were trying to put a policy in place before a General Election, to commence in autumn 2024. The DEFRA plan looked like a normalization of widespread  badger culling into the future. Likely to further stimulate illegal badger culling that is now reported to be rife in some bovine TB areas.

Problems for Defra came from two important interventions. A prompt Freedom of Information request to determine Natural England’s reasons for continuing the licensing of  Supplementary Badger Culling (extension from 4 to up to 9 years of culling) resulted in disclosure of their weak scientific justification (see here). Secondly, legal complaints that the five week consultation period was too short to evaluate the APHA paper and the government’s somewhat confusing interpretation of it, resulted on 19th April, in an extension by 3 weeks of the consultation period, to 13th May (see here).


A pre-action protocol letter for Judicial Review regarding the March proposals to ‘evolve the badger control policy’ was lodged on 16th May (see here). The legal challenge was to the consultation itself, arguing that it was :

  • Misleading and provided inadequate information regarding badger culling efficacy
  • Failed to provide information on potential ecological impacts of the policy
  • Lacked meaningful information on economic impacts of the policy

Ultimately, the consultation fell victim to the announcement by Prime Minister Rishi Sunak on 22nd  May of a General Election on 4th July. This  froze consideration of the consultation responses  until after the election. The Labour Party manifesto for the 2024 General Election was published on 13th June, and stated its intention to end “ineffective” badger culling, as previously pledged during the 2019 general election. Labour had been keeping very quiet about its position on culling in the months leading up to the election. Presumably this was a tactic to placate the farming vote which was needed before Reform UK Party decided to stand. It appeared to have agreed to keep some badger culling going as a part of a back-room deal with the NFU, a fix that was later exposed by reliable sources (see here). 

Meanwhile in Wales, Deputy first Minister of Wales Huw Irranca-Davis in a statement in the Senedd on 14th May 2024 (see here) articulated the superior progress on bovine TB being made in Wales without badger culling: 

“But just to be clear, from 2012, which is the year before badger control policy in England, to 2023, on the latest published data, the herd incidence in England decreased from 9.8 to 7.3; it was a 26 per cent decrease. In Wales, over the same period, herd incidence decreased from 10 to 6.8. It’s a 31.3 per cent decrease. I simply put that on record—those are Department for Environment, Food and Rural Affairs figures, by the way—to say that we are doing things differently in Wales, in line with our programme for government, but we’re also succeeding in many ways.”

Labour’s landslide victory on 4th July heralded a further rollercoaster of events. Within six weeks it announced that the new government did not intend to pursue the policy of ‘targeted’ culling, making the key legal challenge to the consultation unnecessary. Instead it planned to work on a “refreshed bovine TB control badger strategy”.

An important new extensive re-evaluation of the Randomised Badger Culling Trial was published in Nature Scientific Reports by Prof Paul Torgerson with others, on 15th July, shaking the foundation stone of Government policy since 2011. It provided further and highly extensive evidence that the role of badgers in bovine TB in cattle was fatally misconstrued, and the problems had not been spotted over 20 years ago (see here).

Throughout 2023 and 2024 the Oxfordshire Badger Group (OBG), with support from others, had tried to initiate discussion of the RBCT design and findings with Oxford University, but reported a wall of reluctance or silence. Around 7,000 badgers have been shot in Oxfordshire so far. On 18th July OBG presented a petition with over 50,000 signatures to Oxford University School of Biology in central Oxford. OBG called on Oxford University to own what it called “Your Bloody Science” and asked them to “Speak out against badger extermination”, (see here). There was apparently no meaningful contribution to the debate from the Oxford RBCT scientists. Also in July, Betty Badger (AKA Mary Barton, a member of the Herts and Middlesex badger Group) marked her marathon 8 years of protesting badger culling outside Defra’s main London office (every Thursday), switching attention towards the broken promises made to her over the previous year that she “wouldn’t  be standing there after the election” (see here).

On 21st August two new papers were published by Mills et al. in Royal Society Open Science, largely repeating the analyses in Torgerson et al 2024, but coming to a different conclusion (see here & here). Further concerns by Torgerson et al were preprinted on September 20th in BioRxive (see here) and the matter will continue into 2025.

On 23rd August, the BBC2 documentary ‘Brian May – The Badgers, the Farmers, and Me’ was aired, illustrating how the badger cull policy implemented since 2013 has failed farmers completely (see here).

There followed a tirade of rather ill-founded and rushed accusations and complaints by multiple members of the usually secretive BTB Partnership (see here) on X (formerly Twitter), presumably reflecting the collective tribal response of government hirelings. The documentary showed how, following the cull, rates of bTB infection and consequent numbers of cattle slaughtered are in some areas no better than they were in 2013, and in other areas they are worse than ever. See here and the graph below for Gloucestershire cull area 1 that is central to government (APHA) publications; they tell the story. The real culprit, as exposed by leading cattle vet Dick Sibley, is the limitations of the standard SICCT and Gamma testing procedure and constraints over using newer tests to detect the hidden disease reservoir in herds. The work from the Save Me Trust supported case study farms in England and Wales and all pointed in one direction – the misunderstanding of disease control needs by the Government professionals and contractors in charge. Farmers in south west England were beginning to recognize how far away from real solutions the Government and their representatives have been taking them. Both with the trading of herds not properly freed from bTB infection, and the false narrative around badger transmission. The documentary represents the most decisive moment in bovine TB control since the epidemic was created nearly 25 years ago following a long period with lax testing.

Fact: Badger culling has made no visible difference to the number of annual bTB incidents  in the 2013-2021  ‘pilot’ cull area in Gloucestershire. Note 2024 has now reached 26 incidents as of 4th December.


On 30th August,  intent to refresh the bovine TB control badger strategy was announced:

“Government to end badger cull with new TB eradication strategy”,

although only in relation to a bit of proposed tinkering around with badgers, as follows:

  • A new survey starting in December 2024 to try to estimate cull impacts. This will be a sample of signs of sett activity in culled areas and conclude generally that badgers are highly mobile and recolonise quickly, but give no reliable indication of numbers.
  • Surveillance of the prevalence of bTB in found dead or culled badgers and deer. To show, as expected, and previously shown, that bTB remains in wildlife when the general countryside remains infected by infected cattle trading, and afterwards for several years. This seems to be aimed at somehow informing further misguided culling and vaccination efforts, based on outmoded thinking.
  • Establish a new Badger Vaccinator Field Force: As Defra fall  even further and hopelessly behind its badger vaccination targets of 2023 and now 2024, accelerating potential future costs, this ambition looks as futile as it is a pointless exercise. No one thinks it can work, no one wants to do it, no one wants to pay for it. There is no evidence it can contribute.
  • Badger vaccination study to rapidly analyse the effect of badger vaccination on the incidence of TB in cattle: There would be nothing rapid about this and for it to have any value would be a long term, hugely expensive exercise, with controls. The flawed anticipation is that it will “give farmers greater confidence that doing so will have a positive effect on their cattle.”  This just illustrates how misguided and out of touch the same-old Defra/APHA staff and advisors remain.

This was very disappointing to say the least. And whilst there was a clearly stated intention to stop culling badgers, shockingly that would not now happen before the end of the current Parliament (2029), leaving the door open for culling to continue with the next Government. The plans proposed five more years of badger culling and to everyone’s disbelief, even a new cull area in Cumbria north of Penrith. Where unwise cattle trading has created a small number of breakdowns in a zone called Hotspot 29: around 1,000 mostly healthy badgers are to be shot over a wide area (see here and below), with hundreds shot this autumn. It was almost as if Defra/APHA staff wanted to appease the NFU with a “badger culling business as usual” promise no matter what independent reports or the new politicians said. Such is the grip of vested interest on civil servants.

Hotspot 29. Herd breakdowns 2013-2024. Note in 2020 due to covid restrictions, cattle testing was suspended. This resulted in increased trading of diseased cattle and further infections in subsequent years. In 2022 many new enhanced tests began to address the 2021 increase in the area, with the APHA/CVO epidemiological mistake of blaming it on badgers. It is what the 2018 LRA policy calls a ‘precautionary’ measure, and is the travesty of a failed policy that Labour now perpetuates, despite promising not to. There has been a further breakdown in December 2024 making 8 breakdowns.

And so in September, the badger culling season under a Labour administration got into full swing in the High Risk, Edge and Low Risk Areas of England for a 12th year, to kill (often in a cruel way) around 15,000 more mostly completely healthy adult and cub badgers. This will bring the total reported killed since 2013 close to the 250,000 mark.

On 24th October APHA’s “Year End Descriptive Epidemiology Reports” for  Bovine TB control were published online for the Edge Area counties of Berkshire, Buckinghamshire, Cheshire, Derbyshire, East Sussex, Hampshire, Leicestershire, Northamptonshire, Nottinghamshire, Oxfordshire and Warwickshire. Progress is no longer on target for any of these areas, apparently due to inadequate funding for disease control following Brexit cutbacks (see here and here).

Published on 25th October, Science and Politics, a book by by Ian Boyd  appeared to try to distance the author (Defra Chief Scientific Advisor 2012-2019) from his pivotal role in convincing farmers that badgers needed to be culled (see Boyd’s conceptual model below). His role in encouraging the badger cull roll-out  was exposed in court copies of internal Defra emails in 2016. This, despite his self-confession on Civil Service tribalism, having maneuvered in the ‘golden cage’ to deliver ‘Boyd’s cull’ (see here). 

Ian Boyd’s Conceptual model on why badger culling is essential


As the year wound down, the Oxfordshire Badger Group supported a scientific seminar, in Oxford, delivered by Prof. Paul Torgerson on 18th November: key RBCT academics together with Defra & APHA officials were invited to discuss the science and statistics but all declined. 

Baroness Bennett of Manor Castle (Natalie Bennett) hosted a special meeting on Government bovine TB policy at Millbank in Westminster on 19th November, with presentations by Prof Paul Torgerson and veterinarian Dick Sibley. The meeting was well attended from the Lords and Commons, but all Defra and APHA officials and staff invited to attend declined the invitation (see Vet Record: here).

On 28th November,  the Northern Ireland Chief Veterinary Officer Review of Bovine Tuberculosis in Northern Ireland (prepared by cattle breeder Brian Dooher) (see here) was published in advance of publication of a consultation document over policy expected in the spring. This followed the fiasco over the last consultation, where the economic case was not made available and the consultation was determined invalid by the courts thanks to a NI Badger Group/Wild Justice legal challenge. BTB is getting worse in NI and badger blame rhetoric has reached fever pitch, based in part on misuse of the February APHA paper, and DEFRA’s position claiming that badger culling can be shown to work.  DAERA and independent advisors will need to be sure to produce an accurate document this time if the previous failure is not to be repeated, as sadly looks increasingly likely.

On 3rd December, Rob Pownall of Protect The Wild launched a parliamentary petition to end the English badger cull. Standing at around 30,000 signatures at the time of writing, the petition calls for “an immediate end to the cull and the implementation of cattle focused measures to control bTB, rather than what we see as scapegoating wildlife.” As the petition points out, research that has been “peer reviewed and published, shows no evidence that culling badgers reduces confirmed bTB in cattle. Over 230,000 badgers — many healthy — have been killed, disrupting ecosystems without solid scientific justification”. Please add your name to this petition here.

On 13th December Tom Langton delivered a presentation entitled “Veterinary Science, Uncertainty and Politics: TB and wildlife” at the Annual Veterinary Public Health Conference held at Vetsuisse Faculty at Zurich University. This looked at the flawed assumptions made back in the 1970’s that led to badgers being wrongly labelled as a ‘self-perpetuating bTB reservoir‘, on to field trials that tried to show a ‘bTB perturbation effect’, and statistics chosen to ‘prove‘ this as a way to stop culling. And the uncertainty, peer pressure, confirmation bias and reputational defence that has followed on as a consequence. 

What can be expected in 2025? Difficult to say, but with a Labour government now in charge, we have to hope for at least some meaningful dialogue on the scientific, financial and ethical considerations that have just not been heard over the last 12 years. We are looking for more than the ‘same-old’ broken policy and tired old arguments.

Thanks again to the hundreds of active supporters who have generously helped to fund legal work and provided information, analysis and support in so many ways this year. You have surely contributed towards seeing off widespread targeted culling this year. Next year we will continue to demand rapid change in approach to bovine TB policy, a change that is scientifically evidenced, and that will, at last, start to benefit farmers, cows, badgers and the public.  This change must start with meaningful dialogue.

 

 

 

 

 

Important New Parliamentary Petition

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A new parliamentary petition has been launched by Protect the Wild. It states:

The Government’s TB Eradication Strategy allows the continued killing of badgers, a protected species, until the end of this Parliament, despite the Labour manifesto calling the cull “ineffective.”

We believe the badger cull is unjustified and must end.

Some research has suggested culling results in a reduction in bovine TB (bTB) in cattle. However, there are concerns about the methodology used. Other research, which has been peer reviewed and published, shows no evidence that culling badgers reduces confirmed bTB in cattle. Over 230,000 badgers — many healthy — have been killed, disrupting ecosystems without solid scientific justification.

We call for an immediate end to the cull and the implementation of cattle focused measures to control bTB, rather than what we see as scapegoating wildlife.

We fully support this petition and would encourage you to add your name. Encourage others who care about badgers, effective disease control and the correct interpretation of science to sign too. Let’s see it reach 100,000 signatures & get a parliamentary debate.

 

Add your name here.

 

 

Murky dealings in England and NI, and why ineffective badger culling continues

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If it had been known last Christmas that a Labour government would be in power by July of this year, an imminent end of the cull would have been anticipated. With a public inquiry set up into how the killing of 230,000 badgers could ever have been allowed to happen. The science supporting culling has continued to become increasingly uncertain and is now close to breaking point (here) with many learned institutions poised to be shaken over one of the more serious biological  revelations for  a generation.

Labour had pledged that it would  end the cull, even put  a statement in their manifesto that labelled badger culling ‘ineffective’ to send the message to voters. Surely it would end immediately, as ineffective = unlawful to continue. Voters must have had that in mind when they voted. 

Unfortunately, that is not the way things went. True, the plan that would otherwise have moved forward for ‘targeted‘ or ‘epidemiological’ culling was well and truly scrapped (here). But incredibly Defra and Natural England hung on by their fingertips to the increasingly frail scientific justification for the ‘model’ that is the Cumbria Area 32/Hotspot 21 ‘Low Risk Area’ 100% cull. They have added a new cull area next door to its failed exemplar (here). This is to continue until 2027 at least and, just possibly, more areas could be added, potentially  lasting until the end of this Parliament (2029). ‘Intensive’ and ‘Supplementary’ culling remain in place this year and next.

In Cumbria, the area north of the old cull area has been infected with bTB. Why? Because trading of infected stock continues from infected herds incorrectly declared TB-Free nearby, and cattle testing is only done every four years. Which is truly crazy so close to the original hotspot. Farms within 15 Km of hotspots sharing grazing or exchanging stock should quite obviously be on annual or more frequent testing. The breakdown investigation rules actually favour a cluster developing. APHA assumes the recorded breakdown is the index case, not a nearby farm, and allows 30 days for farms within 3.0 Km radius of the breakdown to sell off stock before radial testing begins. It’s a neglectful recipe for creating a TB cluster. It is one of the things Reed and  Zeichner needed to fix in Week 1, and civil servants should have told them so.

Why has  ineffectual TB management perpetuated – why is the new broom still in the cupboard? Apparently, around a year ago, with Labour uncertain of winning a big electoral majority, Steve Reed then the Shadow Secretary of State for Environment, Food and Rural Affairs, gave assurances to the NFU that ‘some’ badger culling would be allowed to continue.  He did this without a good knowledge of the issue, and apparently without the knowledge of Party researchers. It was a sleazy back door deal for political support in 2024.

Over the last four weeks or so in September, badger blood mixed with persistent rain, as around 10,000 badgers were needlessly shot, often inhumanely. More will die this month at an average rate of 300 a day. Another 10,000 or so badgers are to be killed next year, and an unspecified, smaller number will be killed in 2027 until 2029, because Steve Reed made a pre-election commitment to keep culling going – without understanding the real disease control needs – for political gain.

But we have seen this before. In Northern Ireland in 2021 the Ulster Farmers Union had a similar commitment to ‘wildlife intervention’ (i.e. badger culling) from the ‘top’ in DAERA that they were impatient to see brought forward (Case 2021 here). This was done by suggesting that there was a need (unevidenced scientifically) for badger culling to accompany better cattle testing. Dodgy deals behind people’s backs, for political gain, and irrespective of the cost to the  taxpayer. It has to stop.

 

Gloucs Pilot Badger Cull Area no. 1: Farms Still Swamped With Bovine TB

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The figures speaks for themselves. Herd BTB breakdowns in the very first cull area in Gloucestershire have changed little since 2013, after nine years of persistent badger culling.

With a downward trend in ‘confirmed’ (OTFW) breakdowns prior to the start of culling, data is consistent with benefits from continued enhanced cattle controls hitting the limits of their effectiveness. But the poor sensitivity of the skin test has retained diseased cattle less responsive to the SICCT and gamma test, and kept the area as diseased as it was at the start. Elsewhere in  Gloucestershire it’s a similar story. A humiliating moment for Defra and APHA, who know that badger culling is ineffective and that the BTB testing procedures need a revolution, much as they do in Republic of Ireland. There is a dire need to drill down on the disease, especially in the larger dairy herds. Without this £Millions of taxpayer and farmers money will be wasted each week chasing impossible outcomes.

Area 1-Gloucestershire has seen a large percentage rise in number of cattle (up by 20% or 4,124), despite the number of herds decreasing by 13. It is well known that disease rises as herds get larger, so why are the public being asked to support a process that is making things worse? And who is going to step up to resolve the crisis?

Randomised Badger Culling Trial Unsprung – the uncertainties grow

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The continuing questions over uncertainty in the published outcome of the Randomised Badger Culling Trial (RBCT) have rumbled on over the summer of 2024, and were reported on (here). 

Why are the statistical elements of the RBCT so important? Because the government badger cull policy rests all but entirely on them. It was the science that DEFRA has used to create policy and in court to defend their decisions to experiment with badger culling. The RBCT claimed badger culling can reduce bovine TB in cattle; very many subsequent studies are heavily derived from it, to the point that if it is wrong, it will send a wrecking ball through dozens of publications, reports and reviews. The stakes could not be higher.

Disease benefits claimed for badger culling by civil servants and politicians are in reality, far more likely due to implementation of additional cattle measures. But there is continued inference that badger culling is a cause of disease reduction because such benefits might be “predicted” from the results of the RBCT.

The chronology of published and pre-printed science on the statistical analysis of the RBCT as it relates to proactive culling is growing, so here is a summary with clickable links:

16th February 2006, “Positive and negative effects of widespread badger culling on tuberculosis in cattle” was published in Nature by Donnelly et al.. 

10th May 2019, “Badger Culling and Bovine TB in Cattle: A Re Evaluation of Proactive Culling Benefit in the Randomized Badger Culling Trial” was published in the Journal of Dairy and Veterinary Sciences by Langton.

13th December 2022, “Absence of effects of widespread badger culling on tuberculosis in cattle” was posted as a preprint on Research Square by Torgerson et al. .

12th May 2023. A revised version of “Absence of effects of widespread badger culling on tuberculosis in cattle” was pre-printed in Research Square, and submitted to Nature Scientific Reports by Torgerson et al…

15th July 2024. The final version of “Absence of effects of widespread badger culling on tuberculosis in cattle” was published in Nature Scientific Reports by Torgerson et al..

18th August 2024. Interim report on the August 2024 pre-publication response to the July 2024 re-evaluation of evidence and analyses of proactive culling (published in 2006), as a part of the Randomised Badger Culling Trial (RBCT), 1998-2005. Independent pre-publication report on the Mills et al papers to be published on 21.08.2024.

21st August 2024. “An extensive re-evaluation of evidence and analyses of the Randomised Badger Culling Trial (RBCT) I: Within proactive culling areas”  and “An extensive re-evaluation of evidence and analyses of the Randomised Badger Culling Trial II: In neighbouring areas” were published in Royal Society Open Science by Mills et al..

16th September 2024. A ‘Comment’ response to the new Mills et al. 2024 papers was submitted to the Royal Society Open Science: “Randomised Badger Culling Trial lacks evidence for proactive badger culling effect on tuberculosis in cattle: comment on Mills et al. 2024, Parts I & II” by Torgerson et al.. This was pre-printed with bioRxiv on 20th September.

The ‘Comment’ submission to the Royal Society Open Science is an extensive response to the two new Mills et al. (2024) papers which reproduced much of Torgerson et al.’s models, whilst re-interpreting the results.

The abstract of the Torgerson et al. ‘Comment’ is as follows:

Abstract
Re-evaluation of statistical analysis of the Randomised Badger Culling Trial (RBCT) by Torgerson et al. 2024 was rebutted by Mills et al. 2024 Parts I and II. The rebuttal defended the use of count rather than rate when considering bovine tuberculosis herd incidence. The defence makes biologically implausible use of Information Criterion for appraisal diagnostics; overfits data; and has erroneous Bayesian analyses. It favours ‘goodness of fit’ over ‘predictive power’, for a small data set, when the study was to inform application. Importantly, for ‘total’ bTB breakdown: (‘confirmed’ (OTF-W) +‘unconfirmed’ (OTF-S)), where modern interpretation of the main diagnostic bTB test better indicates the incidence rate of herd breakdown, there is no effect in cull and neighbouring areas, across all statistical models. The RBCT was a small, single experiment with unknown factors. With respect to the paradigm of reproducibility and the FAIR principles, the original RBCT analysis and recent efforts to support it are wholly unconvincing. The 2006 conclusion of the RBCT that “badger culling is unlikely to contribute positively to the control of cattle TB in Britain” is supported, but the route to such a position is revised in the light of modern veterinary understanding and statistical reappraisal.

The new Comment, that has not yet been peer-reviewed, highlights what is described as selective reporting, misleading interpretation, implausible model selection and coding anomalies. It will be of interest to Ministers, Civil Servants, scientists and politicians who currently,  under the new Labour administration, are ‘refreshing’ the bovine TB strategy, and policy. 

The two Mills et al. papers were published just a few days before the Intensive and Supplementary badger cull licences were issued for 2024, providing a rationale for culling to continue.

Defra outlines a refreshed bovine TB control badger strategy.

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Defra has today (30th August 2024) announced plans for a refreshed bovine TB control badger strategy. Whilst it is good to see a clearly stated intention to stop culling badgers, that this will not happen before the end of the current parliament (2029) is completely unacceptable. These plans propose five more years of badger culling, all without sound scientific basis, and would result in the total number of culled badgers exceeding 300,000, all with no measurable disease benefit.

It is equally disappointing to see proposals for mass badger vaccination to be employed as a tool against bovine TB in cattle. This is an unwelcome, and scientifically unjustified continuation of the badger blame game. The scientific evidence just does not support the continued focus on badgers as a significant source of bovine TB in cattle, despite ill-informed media reports in recent weeks. It is a complete waste of resources when the real need is to retrain vets on the science of bovine TB and wildlife, over which they have been misled for many years, and to change cattle testing policy.

While we welcome the statement that “The full strategy will be co-designed with farmers, vets, scientists and conservationists”, we are somewhat sceptical about how inclusive this will be. There has been no engagement with scientists involved in important peer-reviewed science (here and here), despite frequent requests for meetings or at least dialogue. Will there be continued resistance to accept published science that challenges the views of those civil servants at Defra who have been pushing un-evidenced, expensive and unethical policy for so long?  An uncomfortable history of bad decision making by those who need to stand aside to allow genuine progress.  

Not mentioned in the statement, is the 22nd August consultation on licensing of a new badger cull  in the Low Risk Area (LRA). It looks likely that Labour are not just re-authorising existing licences, they are planning to start new licences in new areas, this one in Cumbria in the Eden valley north and east of Penrith. This will have a 100% cull objective, repeating the failed epi-cull of the immediately adjoining area, the subject of a report last year (see here).  There are rumours that two further LRA culls may be licenced this autumn or next, possibly in Lincolnshire and Hertfordshire / Bucks and who knows where else?  

Here is the Defra announcement in full:

 

Government to end badger cull with new TB eradication strategy  

  • First Bovine TB strategy in a decade to end badger cull and drive down TB rates to protect farmers livelihoods
  • New holistic approach will ramp up cattle control measures, wildlife monitoring and badger vaccinations
  • Proposals co-designed alongside farmers, vets, scientists, and conservationists to beat TB that devastates livestock farmers and wildlife

Work on a comprehensive new TB eradication strategy has been launched today (30 August) to end the badger cull and drive down Bovine Tuberculosis (TB) rates to save cattle and farmers’ livelihoods.   

Over the past decade, TB has had a devastating impact on threatened British livestock and wildlife. Over 278,000 cattle have been compulsorily slaughtered and over 230,000 badgers have been killed in efforts to control the disease, costing taxpayers more than £100 million every year. 

For the first time in over a decade, the Government will introduce a new bovine TB eradication strategy working with farmers, vets, scientists and conservationists to rapidly strengthen and deploy a range of disease control measures.   

The new strategy will mark a significant step-change in approach to tackle this devastating disease, driving down TB rates and saving farmer livelihoods and businesses. It will use a data-led and scientific approach to end the badger cull by the end of this parliament.   

The work to end the badger cull starts immediately and includes:     

  • First badger population survey in over a decade: The last major badger survey was carried out between 2011-13, leaving policy makers with no clear idea of the impact culling techniques have on our badger populations. The Government will work at pace to launch a new survey this winter to estimate badger abundance and population recovery to illustrate the impact of widespread culling over the past decade.  
  • New national wildlife surveillance programme: After a decade of culling, the prevalence of TB in remaining badger populations is largely unknown. The development of a new national wildlife surveillance programme will provide an up-to-date understanding of disease in badgers and other wildlife such as deer. Together with updated estimates of badger abundance, this will unlock a data-driven approach to inform how and where TB vaccines and other eradication measures are rapidly deployed to drive down TB rates and protect farmers’ livelihoods.   
  • Establish a new Badger Vaccinator Field Force: Badger vaccinations create progressively healthier badger populations that are less susceptible to catching and transmitting TB. A new Badger Vaccinator Field Force will increase badger vaccination at pace to drive down TB rates and protect badgers.   
  • Badger vaccination study: To supplement the Field Force, the Government will rapidly analyse the effect of badger vaccination on the incidence of TB in cattle to encourage farmers to take part and provide greater confidence that doing so will have a positive effect on their cattle.  

In addition, we will accelerate work on the development of a cattle vaccine, whichis at the forefront of innovative solutions to help eradicate this disease. The next stage of field trials will commence in the coming months. Our aim is to deliver an effective cattle TB vaccination strategy within the next few years to accelerate progress towards achieving officially TB free (OTF) status for England.   

The full strategy will be co-designed with farmers, vets, scientists and conservationists. It will consider a range of further measures including boosting cattle testing, reducing the spread of disease through cattle movements, and deploying badger vaccination on a wider, landscape scale. This will build on Professor Sir Charles Godfray’s 2018 independent strategy review.  

Minister for Food Security and Rural Affairs, Daniel Zeichner said:   

“Bovine tuberculosis has devastated British farmers and wildlife for far too long.  

“It has placed dreadful hardship and stress on farmers who continue to suffer the loss of valued herds and has taken a terrible toll on our badger populations.   

“No more. Our comprehensive TB eradication package will allow us to end the badger cull by the end of this parliament and stop the spread of this horrific disease.”   

Chief Veterinary Officer Christine Middlemiss said:   

“Bovine tuberculosis is one of the most difficult and prolonged animal disease challenges we face, causing devastation for farming communities.   

“There is no single way to combat it, and a refreshed strategy will continue to be led by the very best scientific and epidemiological evidence. With the disease on a downward trajectory, we are at a crucial point. Working in collaboration with government and stakeholders will be the only way we achieve our target to eradicate bovine tuberculosis in England by 2038.”  

John Cross, chair of the bTB Partnership said:   

“As chair of the bTB Partnership for England, I am delighted to hear Minister Zeichner’s intention to refresh the current bTB strategy. Ten years after its launch, the time is right to look again at the tools we use to tackle this persistent disease.  

“Bovine TB is the common enemy, not farmers or wildlife groups. Only by working together, will we reach our goal.”   

 The government will also publish additional information about animal and herd-level bTB risk – for example, the date and type of the most recent TB test completed in the herd of origin of that animal and how long the animal has been in the herd.  

This greater level of detail will be made available on ibTB – a free to access interactive map set up to help cattle farmers and their vets understand the level of bovine TB in their area and manage the risks when purchasing cattle.  

Today’s announcement ensures the government meets its manifesto commitment and represents a new direction in defeating this disease that will both protect the farming community and preserve wildlife.    

Notes to editors:  

Existing cull processes will be honoured to ensure clarity for farmers involved in these culls whilst new measures can be rolled out and take effect.    

The Bovine TB Partnership is a stakeholder-government collaboration established as a driving force for further progress towards disease eradication.  It is made up of experts from government (Defra, APHA and Natural England), as well as farmers, veterinarians, scientists, academics, and ecologists/conservationists, including representatives from the National Farmers Union, British Veterinary Association, British Cattle Veterinary Association, and the National Trust.

Department for Environment, Food and Rural Affairs (Defra) This email and any attachments is intended for the named recipient only. If you have received it in error you have no authority to use, disclose, store or copy any of its contents and you should destroy it and inform the sender. Whilst this email and associated attachments will have been checked for known viruses whilst within Defra systems we can accept no responsibility once it has left our systems. Communications on Defra’s computer systems may be monitored and/or recorded to secure the effective operation of the system and for other lawful purposes.

 

More or less? Truth, life and 56%

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August 2024

In life generally people crave the truth, learn from the truth and act on the truth. Truth is the universal source for learning, where trust develops, and where solutions to tackle the myriad of challenges that life throws at us are fostered.

Yet, we all know that absolute truth is a fickle thing. As time passes, new insights evolve, things change. Gradually we may find that what we thought we knew is conditional on certain things, right only some of the time, or even wrong for a clever reason.

So care is needed, especially with the big decisions where large amounts of money, time and effort are employed to address a particular issue or problem.

Take for example the culling of badgers. A Government expert [1] concluded 20 odd years ago that a very small trial study [2] suggested badgers might spread bTB to cattle, especially if frightened away from the setts where they live, and shooting them would help.

Sounds ridiculous? The entire livestock industry eradication policy in GB and Ireland has been based around ‘badger blame’ for the spread of Bovine tuberculosis among cattle herds for two decades. There has been over £2 Billion of subsequent spending and hundreds of thousands of badgers have been culled around a truth that is now uncomfortable to lose, because so many people have enthusiastically believed and embraced it. They own it, and accepting it is wrong messes badly with what they have said and done over the last 20 years.

The matter came into sharp focus in March of 2024, just weeks before the general election was called, with a Government Agency staff academic paper on badger culling effort [3] in England since 2013. This, followed shortly by a DEFRA Public Consultation [4] aimed at extending badger culling for a decade or more, over further huge areas, but with even fewer constraints on when, where and how.

To the general public this is all a mystery. Surveys show that the public largely think that badger culling ended in 2020 when Government said it was ‘phasing it out’, and the new government’s election manifesto view [5] that it has been ‘ineffective’ means it will stop for good. But actually, in the cold night air, from Cornwall to Cumbria, guns with silencers are steadily slaughtering tens of thousands of badgers each autumn. As harvest 2024 is concluding, the culling is now ramping up yet again.

So what about the truth? Well Steve Barclay MP, the old Defra Minister, one of the few seniors to keep his seat during the Labour landslide, had claimed in an ebullient foreword to the March consultation, that a 56% benefit has been gained after four years of culling badgers down to under 30% of their numbers.

So let’s unpack the truth in that. Firstly, the key time marker in all this is 2016 when the first of ten large cull areas were all up and running and followed by around 60 more at a starting rate of around ten a year. Unfortunately for unpicking science and truth, this was also the time that more intensive cattle testing began ramping up. So telling between the effect of culling and testing is not possible, despite what Barclay claimed.

‘Ah’, say the boffins at the Government Agency for badger culling. ‘But without killing badgers, the cattle tests wouldn’t work so well.’

At this point most people switch off….’ I dunno…suppose it’s possible…I’m not that interested  actually….’ It’s one of those speculation moments that is only so interesting given that the facts and alternatives are beyond the non-specialist’s reach and require weeks of fact-checking. This is indeed a complex issue, even for interested parties to consider.

So where did Barclay’s view come from? Well, back in 2012 the coalition government encouraged an academic paper in 2013 [6] that was timed to support badger culling, and that printed its truth, as a part of the justification for mass badger  culling. The paper said a few things that we now know were right and wrong thanks to good old Captain Hindsight.

Right, was that the old small study had been rendered meaningless by a horrendous Foot and Mouth disease outbreak in 2001 [7] that mucked up the experiment’s need for ‘stable countryside’ to be able to monitor change in three of the ten areas – enough to spoil the results. The hapless NFU encouraged rapid restocking with untested TB infected cattle, firing up the bTB epidemic.

Wrong were the calculations that rested upon a belief that cattle do not give bTB to badgers. It was thought to be TB moving all one-way, from badger to cattle, that Defra believed in those days, something that was always suspicious and that modern studies now show is wrong [8-11].

And questionable too was a theory, to try to make the numbers add up in a way no one has ever explained and that looks implausible. That theoretical infections going from badger to cattle are somehow passed on more rapidly than those originating from cattle. Baffling?

Lost already? Well to make the old small study work, the boffins believed that while around 94% of disease was the result of cattle-cattle infection, around 6% was down to badgers. Unfortunately, wildlife groups have believed and utilized these figures, despite warnings, not realising it is part of a dubious study that blames badgers and the king pin in justifying the badger culls since 2013. The so called ‘onward transfer’ of infection from badger to cattle is akin to a biblical myth with no scientific legs, yet it became the truth that key people in Government believed. It was held up as the science to believe in, forming and promoting the badger cull policy. Most cull objectors had realised this by 2016.

Back to Barclay’s 56% and the boffins new paper in March 2024. Despite elaborate graphics, this was a pretty rough-and-ready analysis, looking at before and after culling and substantial cattle testing improvements in the first few years of application, and attributing the decline in herd TB breakdowns to a combination of badger culling and herd testing. It stated (twice) that it is not possible to say which factor caused the change. Yet in a discussion of the results it also said the results were consistent with effects of badger culling seen during the small study, and studies using the small studies assumptions, and this speculation found itself in the paper summary (abstract) at the front.  This now gives an opportunity for apparent disease benefit to masquerade as fact or truth. Hence Barclay and the National Farmers Union ramped up the rhetoric on ‘Badger Culling Works’, and quoted the 56% benefit as a function of badger culling. Not bTB control – the better description of the mix of things being tried. Without evidence. Sunak picked up the mantle and did the same in a shed with farmers shortly before he lost office at the general election.

But the truth, as pointed out by other senior academics observing, is that these public statements were untruthful. Change might or might not have been assisted by badger culling – the very question the small RBCT study 20 odd years ago was supposed to resolve when it came up with a split answer – it possibly does and it possibly doesn’t. Flip a coin. And the real truth is that badger culling could be having some effect or it might all be down to tougher testing and movement control. Saying badger culling helped from 2013 or was pivotal or a catalyst is a bit like any of the innumerable causation arguments that created problems in science before they were recognized for what they were during the 1960’s [12].  Association is not the same as causation. Would anyone propose that Donald Trump being elected as President in 2016 caused bovine TB to start to fall? Well it happened at the same time, and bTB has come down since………..Or was the fall in TB the result of a general switch to tougher testing?

The problem for truth in this case is that Governments need to make decisions, and where there is uncertainty they need to have a plan. But Government scientists presenting their opinions as fact, for politicians and stakeholders to believe and to repeat, is a deception. A dangerous step and something that needs weeding out by journals employing peer-reviewers. And hopefully not by mournful inquiries years later, charged with working out how it all went wrong. The problem here is that there are few people experienced enough to understand and judge boffin science, and so you find your mate reviewing your work, and you review your mates work, and bad habits develop. Bovine TB science is plentiful and this syndrome sees awkward material published quite often; it provides a good exemplar of the issue called the reproducibility crisis [13]. All the Government scientists need to say is we ‘think’ it might be working because…. that is a long way from saying it ‘is’ – think snake oil salesman. It matters, it matters a lot when lots of lives and money are at stake. It matters because lying to the public is undemocratic and wrong.

So if someone asks you about badger culling, you might just say – ‘well its complicated and I don’t know.‘ But if they pick up a gun to shoot a badger, you might just say ‘hang on – I think you might be breaking the law’. Which requires evidence, and sufficient clarity that mass killing badgers to prevent the spread of bovine TB can be justified. And after 20 years there is no truth to suggest it does, only guesswork. However, cattle testing and movement control has worked in England and Wales without badger culling, so using that proven remedy is justified with some confidence and is an honest approach, if truth be told.

References

1. King, D. 2007 Bovine tuberculosis in cattle and badgers. A report by the Chief Scientific Advisor, Sir David King, to the Secretary of State for Defra on 30 July  2007. 

2. Donnelly, C. A. et al. Positive and negative effects of widespread badger culling on tuberculosis in cattle. Nature 439, 843–846 (2006).

3. Birch, C. P. D. et al. Difference in differences analysis evaluates the effects of the badger control policy on bovine tuberculosis in England. Sci Rep 14, 4849. https://doi.org/10.1038/s41598-024-54062-4 (2024).

4. DEFRA 2024 Bovine TB: Consultation on proposals to evolve badger control policy and introduce additional cattle measures. A consultation exercise contributing to the delivery of the government’s strategy for achieving bovine tuberculosis free status in England..

5. Labour Party manifesto https://labour.org.uk/change/        

6. Donnelly, C. A. & Nouvellet, P. The contribution of badgers to confirmed tuberculosis in cattle in high-incidence areas in England. PLoS Curr. 10, 5 (2013).

7. Private Eye 2001 Special Report. Not The Foot And Mouth Report. London

8. Biek R, O’Hare A, Wright D, Mallon T, McCormick C, Orton RJ, McDowell S, Trewby H, Skuce RA, Kao RR. Whole genome sequencing reveals local transmission patterns of Mycobacterium bovis in sympatric cattle and badger populations. PLoS Pathog. 2012;8(11):e1003008. doi: 10.1371/journal.ppat.1003008. Epub 2012 Nov 29. PMID: 23209404; PMCID: PMC3510252.

9. Crispell J, Benton CH, Balaz D, De Maio N, Ahkmetova A, Allen A, et al. Combining genomics and epidemiology to analyse bi-directional transmission of Mycobacterium bovis in a multi-host system. Elife. 2019;8

10. Akhmetova, A; Guerrero, J; McAdam, P; Salvador, LC; Crispell, J; Lavery, J; Presho, E; Kao, RR; Biek, R; Menzies, F et al. 2021. Genomic epidemiology of Mycobacterium bovis infection in sympatric badger and cattle populations in Northern Ireland. bioRxiv 2021.03.12.435101; doi: https://doi. org/10.1101/2021.03.12.435101

11. van Tonder AJ, Thornton MJ, Conlan AJK, Jolley KA, Goolding L, Mitchell AP, Dale J, Palkopoulou E, Hogarth PJ, Hewinson RG, Wood JLN, Parkhill J. Inferring Mycobacterium bovis transmission between cattle and badgers using isolates from the Randomised Badger Culling Trial. PLoS Pathog. 2021 Nov 29;17(11):e1010075. doi: 10.1371/journal.ppat.1010075. PMID: 34843579; PMCID: PMC8659364.

12. Hill, Austin Bradford. “The Environment and Disease: Association or Causation?.” Proceedings of the Royal Society of Medicine 58 (1965): 295.

13. Baker, Monya, 2016, “1,500 Scientists Lift the Lid on Reproducibility”, Nature, 533(7604): 452–454. doi:10.1038/533452a

 

 

Brian May – The Badgers, the Farmers, and Me

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Brian May: The Badgers, the Farmers, and Me’ is a documentary that was aired on BBC2 at 9.00pm on Friday 23 August, and is now available on the BBC iplayer. Filmed over 4 years, the programme charts Brian May’s journey as he explores the ongoing battle against bovine tuberculosis, and the differing views of both farmers and those who oppose badger culling .

The new film covers 12 years of practical research ongoing over the last 12 years. The shocking truth around the monumental failure of Defra to effectively address the problem of bovine TB  is highlighted, and the resulting tragic slaughter of both cows and badgers is revealed with horrible clarity.

Animal campaigner Brian May and Anne Brummer, CEO of May’s Save-Me organization, have spent the years since culling was first mooted by David Cameron’s government uncovering the truth about bovine TB. Rather than fighting the farmers, May and Brummer have looked at the problem from the viewpoint of the farmer and the vet , following a case study which has transformed a chronically infected cattle herd into a healthy herd with TB-free status. This was achieved without killing a single badger. The revolutionary methods used are now known as the Gatcombe strategy.

Meanwhile, over the same period, nearly a quarter of a million badgers have been killed on the basis that they spread bTB to cattle. This new documentary shows that the badger cull policy implemented since 2013 has failed farmers completely. Rates of bTB infection and consequent numbers of cattle slaughtered are in some areas no better, and in others worse than ever, following the cull. The work from the case study farm in the documentary clearly shows with that blaming badgers has been a wildly incorrect reading of the facts.

May and Brummer conclude that the very idea that badgers are part of the bTB re-infection process is unsupportable. Government and NFU policy has been based on the work of a small number of scientists who have persisted in claiming disease benefit  from  statistical models, ignoring the uncertainty around them, and doubling-down when challenged.

This new documentary is the first time that an alternative view about badger culling has been presented in documentary format. Do watch it for a sincere, refreshing and honest take on badger culling. It goes to the heart of the problem, and shows compassion for the farmers, the cattle and badgers. And it provides answers and a way forward. Congratulations to all involved. 

Available on the BBC iplayer here.

 

RBCT uncertainties debate gains momentum

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On December 13th 2022, a preprint was put up on the ResearchSquare platform. Entitled ‘Absence of effects of widespread badger culling on tuberculosis in cattle’ [1], it was a reanalysis of the Randomized Badger Culling Trials (RBCT). Following a protracted period of review, with a number of very long silences, and relatively few revisions, it was published in Nature Scientific Reports on July 15th 2024 (Torgerson et al 2024) [2]. Finding a major anomaly, it uses a range of statistical models to re-examine the RBCT data  and concludes that most standard analytical options did not show any evidence to support an effect of badger culling on bovine TB in cattle.

Torgerson et al 2024 [2] noted that the statistical model selected for use in the original study in 2006 [5] was one of the few models that did show an effect from badger culling. However, various model assessment criteria suggest that the original model was not an optimal model compared to other options available. You can read a short blog on the new Torgerson et al paper here, and the full paper is available here. Essentially, the more appropriate models in the latest study strongly suggest that badger culling does not bring about the disease reduction reported.

Following publication, the new analysis [2] was mentioned in an article in Vet Times on July 24th, and in Vet Record in their 3/10 August edition. Neither publication noted its major significance. No other mainstream media reported on it at all. This is perhaps surprising since the government badger cull policy rests all but entirely on the conclusions from the RBCT. It is the science that DEFRA has used in court to defend their decisions to experiment with culling. It is the science that has resulted in 11 (12 including 2024) years of intensive and supplementary badger culling across huge areas of England, and around 230,000 dead badgers. In other words it is the pivotal piece of work for the decision-making around badger culling policy.

The reluctance of the media to report further on Torgerson et al. is a prelude to work by two of the authors of the original 2006 analysis (Christl Donnelly and Rosie Woodroffe) together with a DPhil Statistics student at Oxford University (Cathal Mills), who had, at the time of publication, two rebuttal papers in press with Royal Society Open Science [3,4]. Unusually, the abstracts and supplementary information for these new papers were posted online and available to view before publication without the main text. Enquiries regarding the posted information and the main papers resulted in in press versions being helpfully forwarded. The new analyses from Mills et al. are entitled An extensive re-evaluation of evidence and  analyses of the Randomised Badger Culling Trial (RBCT) I: Within proactive culling areas [3], and  An extensive re-evaluation of evidence and analyses of the Randomised Badger Culling Trial II: In neighbouring areas [4].

Published on August 21st, the two new papers largely duplicate the analyses in Torgerson et al 2024, but use different model assessment criterion to come to a different conclusion. In fact they double-down on the conclusions of the original 2006 analysis: “…we estimate substantial beneficial effects of proactive culling within culling areas, consistent with separate, existing, peer-reviewed analyses of the RBCT data.”

So in the year and a half since the posting of the Torgerson pre-print [1], Mills, Woodroffe and Donnelly have been working on their rebuttal to it. Torgerson and his team have looked through the in press versions of the Mills et al (2024) publications [3,4] for a few days and multiple problems stand out. In particular:

  1. Incorrect statements regarding disease control outcomes since 2010
  2. Use of a non-peer reviewed publication
  3. Confusion between the offset and overdispersion leading to incorrect calculation of disease exposure
  4. Incorrect and confused statements regarding model comparisons
  5. Exaggerated claims during use of new modelling.
  6. Failure to address the modern interpretation of SICCT test reactors
  7. Failure to recognise the onward effect of the analytical failure on multiple subsequent publications and policy outcomes.

Somewhat unusually, the new Mills et al papers do not refer to or cite the published Torgerson et al paper [2], only the first pre-printed version of Torgerson et al. from 2022 [1]. So in essence, the new Mills et al papers [3,4] are out of date at the time of publication, failing to refer to the updated 2023 preprint or the final version in  Scientific Reports published 15th July 2024 [2]. Following contact with the Royal Society, a response raising concerns with the newly published papers is being written and will be submitted shortly. An interim report has been put together by Torgerson and Langton with brief observations on the new papers (see here).

The Royal Society says it is committed to reproducibility. Reproducibility is the ability of independent investigators to draw the same conclusions from an experiment by following the documentation shared by the original investigators [6]. The issues identified in [2] and “rebutted” in [3,4] illustrate one of the major issues of the reproducibility crisis: poor statistical inference. It is hoped that the conclusions of this exchange will inform future bovine TB intervention policy this autumn.

References

[1] Torgerson P, Hartnack S, Rasmusen P, Lewis F, Langton T. 2022 Absence of effects of widespread badger culling on tuberculosis in cattle. In Review. (doi:10.21203/rs.3.rs-2362912/v1)

[2] Torgerson, P.R., Hartnack, S., Rasmussen, P. et al. Absence of effects of widespread badger culling on tuberculosis in cattle. Sci Rep 14, 16326 (2024). https://doi.org/10.1038/s41598-024-67160 (available: https://www.nature.com/articles/s41598-024-67160-0)

[3] Mills CL, Woodroffe R, Donnelly CA. 2024,  An extensive re-evaluation of evidence and analyses of the Randomised Badger Culling Trial (RBCT) I: Within proactive culling areas. R. Soc. Open Sci. (doi:10.1098/rsos.240385)

[4] Mills CL, Woodroffe R, Donnelly CA. 2024, An extensive re-evaluation of evidence and analyses of the Randomised Badger Culling Trial II: In neighbouring areas. R. Soc. Open Sci. 11:240386.

[5] Donnelly CA, Woodroffe R, Cox DR, Bourne FJ, Cheeseman CL, Clifton-Hadley RS, Wei G, Gettinby G, Gilks P, Jenkins H, Johnston WT. Positive and negative effects of widespread badger culling on tuberculosis in cattle. Nature. 2006 Feb 16;439(7078):843-6.

[6] Gundersen Odd Erik 2021The fundamental principles of reproducibility. Phil. Trans. R. Soc. A. 37920200210

 

 

Why are we waiting?

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Things are starting to become slightly clearer as we near the point of discovery over the future of badger culling in England and beyond. Consultees to the online Defra Consultation  questionnaire of 14th March were told this Monday (5th August) that an analysis of Consultation responses will be published in the autumn (Sept-Nov?) giving more time for policy development without badger culling. But there is no reason now to delay clarification on the big 56% lie surrounding the ineffective badger culls.



 

Notably, the NFU appeared fully taken in by the spin from the Animal and Plant Health Agency paper by Colin Birch and Defra, that badger culling ‘is working’. Birch et al. follows on from a paper published in Veterinary Record in 2022 that showed quite neatly how recorded bovine TB levels (recorded OTF-W incidence)  peaked after the introduction of annual tuberculin testing in 2010 and began dropping in the High Risk Area from 2013 in some counties and generally by 2015. And, at a steady rate that did not increase once badger culling started (and that was more widespread from 2018), showing no evidence that badger culling had contributed to a slow decline of around 6% per year. 

Steve Barclay, and previous Environment Ministers before him, had made wild claims of a culling benefit of around 50%, based on APHA parroting the claims made since the 1970s that this is the badger contribution to cattle TB. This has always been a poorly evidenced, lame and far-fetched claim, making a mockery of professional epidemiology.

Not to be fooled, Labour are onto the problem and have firmly labelled badger culling as ‘ineffective’ in their manifesto. They have highlighted the need to work with farmers and scientists which is now the helpful – but not very specific – new Defra mantra.

The Birch paper makes it quite clear in two places that the cause of the welcome decline in bTB first identified formally in 2022, cannot be attributed to any particular intervention, be it better testing, different tests and more frequent tests, better biosecurity or badger culling. It is just a crude before-and-after effort with no controls, showing what was already known in a slightly clunky way. This is no help at all, as Professor Macdonald at Oxford pointed out in his November 2023 ‘state of the science’ review. However, the unfortunately misleading abstract for the Birch paper transmutes opinion into ‘fact’, to give the casual  reader a misinformed overview of the findings. How very CVO.

So what are we left with as we approach the time of Labour’s big reveal this month? Firstly, an increased interest in badger vaccination with Defra organising a media spree with its dutiful contractors to suggest a direction of travel that Natural England seem to think is appropriate.

Also, news from Oxford, where a 50,000 signature petition to the School of Biological Science, organised by the Oxfordshire Badger Group calling for increased academic engagement seems to be working. A response to the Torgerson et al. 2024 paper on the choice of models for analysis of the Randomised Badger Culling Trial data, published  recently in Scientific Reports is imminent. The Torgerson paper wallowed rather oddly for 18 months in peer review, emerging little changed, so plenty of time for the RBCT folk to have prepared.

How the 50 something % cull benefit lie has been peddled in recent months and years:

Farmers Weekly: Badger culling policy reduces cattle TB by 56%, study shows 

Farmers Guardian, Farming matters: Lord Robert Douglas-Miller – ‘The science is clear that the tide is turning on bovine TB’ 

Shrewsbury Conservatives, DANIEL KAWCZYNSKI MP MEETS WITH MARK SPENCER, THE MINISTER OF STATE FOR FOOD, FARMING, AND FISHERIES, URGING HIM TO TAKE TOUGHER ACTION TO REDUCE CASES OF BOVINE TUBERCULOSIS:  

Parliamentary Question response from Mark Spencer: To ask the Secretary of State for Environment, Food and Rural Affairs, what assessment her Department has made of the (a) effectiveness of badger culls in tackling bovine TB and (b) reliability of the TB test used to identify cattle for slaughter; and what estimate her Department has made of the (i) annual cost of bovine TB in Shropshire and (ii) level of bovine TB in that county. 

 

Natural England’s rationale for licensing ineffective Supplementary Badger Culling

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Peter Brotherton, Director of Science at Natural England, issued his “Advice to Natural England’s Operations Team on Supplementary Badger Culling 2024” in April 2024, see here. It was released under Freedom of Information at the end of May.

So how is supplementary culling being justified?

Brotherton considers that the ‘key insights’ arising from his appraisal are that “disease reduction benefits to cattle achieved through badger culling are sustained in the long term (likely at least 7 years post-cull).” And what is this based on? Brotherton says:

“The most relevant evidence to the current English situation is from Donnelly (2013) who found from the Randomised Badger Control Trial (RBCT) that the disease reduction benefits from four years of intensive culling of badgers are greatest 1-2 years post-cull and are sustained for at least 7 years, albeit at a diminishing level over this period.”

Professor Paul Torgerson, Chair, Veterinary Epidemiology, University of Zurich

The problem for this justification now, is that Donnelly (2013) (an unpublished report) is overturned by the new peer-reviewed paper by Torgerson et al (2024). Published since Brotherton issued his advice, “Absence of effects of widespread badger culling on tuberculosis in cattle” has shown that the original RBCT analysis (Donnelly et al 2006) used an inappropriate calculation of rate, when face value calculation of rates was available. When rates are calculated in the standard way, no effect of culling was found. Many subsequent studies, like Donnelly & Nouvellet (2013) which recycle the approach of that analysis should now be considered unsafe. There are dozens, possibly hundreds of them.

Brotherton also references two small studies, Byrne et al 2014 (4 areas in Ireland) and Clifton-Hadley 1995 (2 areas in south-west England) which he acknowledges may be less relevant to the current English context. They are too small in scale to be able more than anecdotal or provide any certainty. They certainly should not be used as substantive evidence.

And that seems to be pretty much it in terms of published evidence. There is some speculation without evidence. There is a mention of badger vaccination reducing the prevalence of bTB in badgers, but any assumption of this reducing disease in cattle is not based on sound evidence. It should be noted that Natural England keep away from their ‘Uncertainty Standard’ that they previously reported as scrapped, but now seem to want to retain .. its all a bit uncertain at Natural England.

Notably, Brotherton does not refer to the main peer-reviewed and published badger culling  analysis Langton et al (2022) in his ‘rationale’, presumably favouring the Chief Vets unqualified comments. This compared culled and unculled areas after 7 years of industry-led badger culling (2013-2019) and found no measurable benefit.

Also of note is Brotherton’s recollection of the advice of the previous Chief Scientific Advisor Prof. Boyd, who “stressed the limits in the evidence base and the importance of adjusting the policy as new evidence becomes available.“ There is no sign that the evidence of peer-reviewed Langton et al (2022) and Torgerson et al (2024) is being recognized by NE yet.

Badger Crowd understands that Natural England have received a letter requesting that supplementary badger cull licences should be revoked on the basis of new published science. It’s well past time to stop the badger cull immediately on the scientific evidence, and not least the comprehensive peer-reviewed evidence.