Badgers and bovine TB: the problem with the “facts” being promoted
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Badger Trust examines the scientific evidence and data behind some key claims about badger culling in England, as presented on the “Share the Facts” page of the TB Free England website (2).
As Wales approaches the Senedd elections, voters are being presented with confident claims about how to tackle bovine tuberculosis (bTB), particularly the assertion that badger culling is a proven solution.
But these claims do not reflect the full scientific evidence. They are selective interpretations, not established facts.
Bovine TB is a serious issue for farmers, but decisions on how to tackle it must be based on complete and accurate evidence, not headline figures taken out of context.
Wales is already showing that progress is possible without wildlife intervention. In the 12 months to December 2025, cattle slaughtered due to bTB fell by 13.6% (1), following a science-led approach focused on cattle measures such as improved testing, movement controls, biosecurity & hygiene (on and off farm).
The Claim
“After four years of wildlife controls, TB incidents typically fell by 56%”
The cited source: Nature.com, Birch et al 2024 - Effects of the badger control policy on bTB in England (3)
Concern: This figure is misleading and presented in a way that implies badger culling led to a 56% reduction in TB incidents.
What the evidence actually shows:
The 56% figure is not a direct reduction in TB incidents. It comes from a modelled comparison of areas without the Badger Control Policy (BCP) versus areas after four years of BCP intervention.
The study estimates that without the policy, the incidence rate would be around 0.145 OTFW incidents per herd-year, compared with 0.065 after four years of BCP, equating to a modelled reduction of about 56%.
However, this is a modelled ‘what-if’ estimate, not a measured fall in recorded TB cases over time. It compares different conditions (with vs without the policy), rather than tracking a simple before-and-after change.
Crucially, the “Badger Control Policy” also includes multiple simultaneous interventions, including improved cattle testing (including interferon gamma testing), movement controls, and other biosecurity & hygiene measures.
The authors clearly state that their analysis “cannot explicitly distinguish the effects of the policy’s component measures.” (4)
The reduction, therefore, cannot be attributed to culling alone.
Badger Trust has written legal correspondence from the Defra Secretary confirming that the ‘badger control policy in the Birch research consists of badger culling alongside cattle controls, including further interferon gamma testing’ (5)
Real-world indicators do not show a 56% fall. APHA and Defra data show cattle slaughtered due to bTB remains broadly stable over time (~0.4 - 0.6% depending on year and testing regime), with no clear step-change reduction attributable to any single intervention (6).
This is not a 56% reduction.
Conclusion: The reported reduction in TB incidents is incorrect, and even the correct measure of herd risk per herd year cannot be attributed to badger culling. The “56%” is a modelled change in risk over time under multiple interventions, not evidence that badger culling reduced TB by 56%.
Where are the 56% fewer infected cattle or herds?
The Claim
“More than 52% of new TB incidents in high-risk areas are attributed to badgers”
Cited source: gov.uk - Bovine Tuberculosis in England in 2021.(7)
Concern: This statistic is often interpreted as direct evidence that badgers are responsible for the majority of new infections.
What the evidence actually shows:
This figure is not based on confirmed transmission pathways. It comes from APHA Disease Report Forms, where veterinarians assign likely “risk pathways” during herd breakdown investigations using a limited set of predefined options.
The methodology itself is not fully published and has only been partially accessed through Freedom of Information requests. Assessments are based on judgement and can include the selection of potential infection sources even in the absence of direct evidence or tracing data.
As highlighted in the independent critique (8), these judgements are inherently subjective and often rely on assumptions, including the presence of badgers being taken as indicative of possible involvement, rather than proven transmission. The uncertainty in these assessments is not reflected in headline percentages.
This data cannot therefore be relied upon and could be highly misleading to those to whom it is reported - primarily the farmers whose herds have suffered a breakdown. Yet, the figures are frequently presented in public and policy debate as if they represent confirmed causes of infection.
We have long been troubled by what appears to be an unnecessarily selective and uninformative approach to communication with farmers when what farmers need most of all is transparency and accurate information.
Conclusion: This statistic reflects selective information gathering, uncertainty and personal judgment rather than confirmed evidence that badgers are a primary source of infection.
The Claim
“Wildlife control is proven to reduce bovine TB - (Gloucestershire 66% reduction, Somerset 37% reduction”
The cited source: Nature.com - Assessing effects from four years of industry-led badger culling in England on the incidence of bovine tuberculosis in cattle (2013-2017) - Downs et al 2019. (9)
Concern: These figures are presented as evidence that removing badgers reduces bTB in cattle.
What the evidence actually shows:
The authors of the study clearly acknowledge this limitation, stating: “These data alone cannot demonstrate whether the badger control policy is effective in reducing bovine TB in cattle.” (10)
The Downs Report, like other studies, found that badger culling could not be proven to prevent or cut bTB in cattle, partly because it was not carried out in isolation. It was part of a broader strategy that included enhanced cattle testing, stricter biosecurity &hygiene measures, and the selection of high-risk areas, alongside a number of other variables.
Because of this, it was impossible to determine whether any observed changes in the incidence of tuberculosis (TB) in cattle are attributable solely to culling.
Furthermore, the widely cited reductions relate to a limited number of cull areas and time periods. In some cases, TB incidence subsequently increased again despite continued culling, for example, rising significantly in Gloucestershire by 130% the year after the study period (11).
Other analyses of the same data have also identified mixed outcomes, including increases in disease prevalence in all these areas (12).
Who is to say that these other measures, focusing on cattle, which are the main drivers of the disease (94-95% cattle-cattle transmission (13)), are not the reason for a reduction in bTB?
Selective use of statistics in public messaging
The Welsh NFU, like many other entirely legitimate industry bodies, has released its manifesto ahead of the Senedd Elections on 7 May.
The NFUOnline (14) details the manifesto with a foreword by NFU Cymru President. The document section ‘A genuine Bovine TB eradication strategy for Wales’ states multiple ‘statistics’. Whilst they are given citations, they do not reflect the conclusions of the body of evidence to date, nor do they tell the full story of even the evidence they offer citations for, and should not therefore be taken at face value or used to justify policy positions.
The Claim
“12,493 cattle were slaughtered in Wales in the year to September 2025, an increase of 2%”
Concern: An interesting period of time to use, had the full year been used as might have been expected, the data would have shown a very different picture. That alone should raise concerns for everyone. This figure is drawn from a non-standard reporting period and does not reflect the most recent full-year data, which would be the usual data reporting period.
What the evidence actually shows:
Official statistics for the 12 months to December 2025 report 11,257 cattle slaughtered due to bTB, a 13.6% decrease from the previous year. (15)
Conclusion: Using selective timeframes can create a misleading impression of trends, especially when more recent data indicate improvement rather than the claimed deterioration as painted by the selective data set. So, why hasn’t the NFU included the latest statistics? Why did it choose the particular selection with which to illustrate its overall story of policy failure?
The real problem is Bovine TB
Bovine Tb is a serious issue in cattle. Cattle health and the farming industry are not helped by data which appears to have been selectively used and, at times, misrepresented in ways that place disproportionate emphasis on wildlife in general and badgers in particular.
Good policy must focus on the real causes of a problem, not on measures that have failed to deliver proven, measurable results. Yet selective statistics are too often presented as clear-cut proof to justify policies that result in the large-scale killing of a protected native species, without evidence that they work.
While bovine TB is complex, one point is clear: the overwhelming majority of transmission is cattle-to-cattle.
Current research does not demonstrate that badger culling delivers measurable, sustained reductions in bovine TB in cattle. What it does show is that progress is linked to cattle-based measures, including more sensitive testing, stricter movement controls, and improved biosecurity & hygiene (on & off farm).
Researchers themselves consistently highlight multiple influencing factors and make clear that outcomes cannot be attributed to culling. It is odd that those whose primary goal is to protect the interests of the farming industry never quote those parts of any study.
With over 250,000 badgers killed in England and the disease still persistent, the continued focus on badgers, whether through culling or vaccination, is difficult to justify as a disease control strategy.
A credible eradication strategy must therefore prioritise:
measures targeting cattle-to-cattle transmission
effective and sensitive testing regimes, ideally substituting segregation for slaughter
stronger biosecurity, on farm hygiene (as with other infectious cattle diseases) and movement controls
clear, evidence-based support for farmers
As Wales looks ahead, there is a clear choice. Policy and public messaging must reflect the full scientific picture, not selective interpretations of evidence, and focus on the main driver of infection: cattle.
Farmers deserve clarity and honesty about what works. Too often, a lack of transparency has limited their ability to respond effectively, while adding to the stress they already face.
The NFU rightly states that ‘TB breakdowns place significant emotional and financial strain on farming families’. However, when evidence is selectively presented or taken out of context, it risks adding further confusion rather than clarity, undermining the very people who most need clear and reliable information to respond effectively to the disease.
Wales has the opportunity to lead with a more effective, evidence-based approach, one that focuses on the real source of the disease and supports farmers with solutions that work.
Badger Trust wants to see Wales and the Welsh livestock industry lead the world in addressing bTB with non lethal measures for cattle just because of a test result: we would be puzzled by anyone in the industry or the Senedd who didn’t want the same thing.
References
Nature.com, Birch et al 2024 - Effects of the badger control policy on bTB in England
Birch, C.P.D., Bakrania, M., Prosser, A. et al. Difference in differences analysis evaluates the effects of the badger control policy on bovine tuberculosis in England. Sci Rep 14, 4849 (2024). https://doi.org/10.1038/s41598-024-54062-4
Email from Secretary of State Legal Team to Badger Trust Legal Team
https://www.gov.uk/government/collections/bovine-tuberculosis-in-england and https://www.gov.uk/government/collections/agriculture-in-the-united-kingdom
Gov.uk - Quarterly TB in cattle in Great Britain statistics notice: March 2024
Downs et al, Assessing effects from four years of industry-led badger culling in England on the incidence of bovine tuberculosis in cattle, 2013–2017 https://www.nature.com/articles/s41598-019-49957-6
Downs et al, Assessing effects from four years of industry-led badger culling in England on the incidence of bovine tuberculosis in cattle, 2013–2017 https://www.nature.com/articles/s41598-019-49957-6 Scientific Reports, 9(1), p.14666
https://www.gov.uk/government/statistics/bovine-tuberculosis-in-england-2020
Cattle infectivity is driving the bTB epidemic, McGill & Jones (2019): https://bvajournals.onlinelibrary.wiley.com/doi/abs/10.1136/vr.l6845
Akhmetova, A., Guerrero, J., McAdam, P., Salvador, L.C., Crispell, J., Lavery, J., Presho, E., Kao, R.R., Biek, R., Menzies, F. and Trimble, N., 2023. Genomic epidemiology of Mycobacterium bovis infection in sympatric badger and cattle populations in Northern Ireland. Microbial Genomics, 9(5), p.001023.
https://www.nfuonline.com/news/senedd-election-manifesto-2026/