Badger Trust challenges BCVA criticism of Brian May documentary

Cattle organisation’s refusal to consider new evidence fails farmers looking for reputable information about how to control bTB spread.

The release of the documentary “Brian May: The Badgers, The Farmers and Me” aired on the 23rd August 2024, was a much-needed public presentation of the true failings of the current bTB policy.

Unfortunately, not everyone respected this evidence-based documentary that firmly puts cattle as the main source of spreading bTB to other cattle.  The narrative that has been told publicly for many years portrays the badger as a significant bTB-spreading enemy to cattle, and it is this story that has enabled the mass killing of over 230,000 badgers.

Sadly, the British Cattle Veterinary Association (BCVA)  was not open to considering this evidence and firmly wanted to stick to the old narrative. In a statement released online, the BCVA’s continued cherry-picking of data to support their point of view is letting down farmers who look to them for reputable information, and it is letting down the majority of the public who want to see an end to the killing of our protected native species.

Here, we share with you our rebuttal to the BCVA written by our Trustee and long-term farm vet, Dr Guda van der Burgt.

16 September 2024

Badger Trust Response to BCVA Statement following BBC broadcast “Brian May: The Badgers, The Farmers and Me” aired on the 23rd August 2024.

Badger Trust would like to respond to the BCVA statement following the BBC2 programme by Sir Brian May on the 23rd August 2024.

BCVA’s rather defensive statement claims that it is essential to take an evidence-based approach based on the latest research and that “opinions aren’t facts”. Perhaps it would be useful to look at all the latest evidence rather than just use some hand-picked papers mostly authored by DEFRA employees.

The BCVA objects to the phrase “Killing Badgers” used in the programme, rather than the more obscure “Culling Badgers”. The Cambridge Dictionary defines “Culling” as “Killing animals, especially the weaker members of a particular group of them to reduce or limit their number”. As the badger culls do not target weaker badgers but any badger, killing is a perfectly accurate term to describe shooting badgers as part of the badger culls. Badgers are killed indiscriminately over large areas.

Dick Sibley said at the start of their experiment that no progress on bTB control in Devon cattle had been achieved after five years of culling badgers, and TB in mid-Devon had actually gotten worse in that time. He did not comment on the Devon TB status in 2024.

Of course, the evidence that Mycobacterium bovis is present in manure and slurry is nothing new (McNallan et al., 2014), nor is the notion that bTB can spread orally (Doran et al, 2009). Calves can contract M.bovis infection through drinking contaminated milk, and so can humans. And indeed, the BBC programme is based on an experiment on one single farm with an ongoing TB problem. Perhaps BCVA members might like to repeat the experiment to find out if the findings are repeatable.

The BCVA is disappointed that “newer evidence was not referred to”. The BCVA then goes on to reference “the most recent studies”(Birch et al., 2024, Downs et al., 2019). In both those studies, it is not demonstrated that the reduction in bovine TB is due to increased cattle measures, badger culling or both.  We will never know, as no control area was only subject to increased cattle measures [1], in the absence of badger culling. Birch states: “this data analysis cannot explicitly distinguish the effects of the Badger Cull Policy’s component measures”.  We cannot be sure that badger culling itself had any effect. The Downs study shows reductions in bovine TB incidents in cattle in Gloucestershire and Somerset between 2013-2017. The data found no change in cattle bTB incidents in Dorset during the same period. However, outside of the study period (2017-18), cattle bTB incidents in Gloucestershire increased by 130% (McGill & Jones, 2019).      

BCVA wrongly quotes: “after 4 years of culling TB incidence reduced”— this should read “after four years of increased cattle biosecurity, increased cattle testing and killing badgers, cattle TB incidence reduced in these hand-picked years and we do not know for certain which measure(s) caused the reduction”.

BCVA appears somewhat selective in quoting the latest research. BCVA does not mention the peer reviewed Langton paper in the Vet Record (2022) that demonstrates no effect whatsoever of the badger culls on the TB incidence in cattle. Why was this paper not mentioned? Did it not fit the BCVA opinion? 

Badger Trust entirely agrees that the sensitivity of the skin test leaves something to be desired. However, with a stated sensitivity between 50% and 80%, it is just as odd to claim a sensitivity of 50% (Brian May/Dick Sibley) as it is to claim an average sensitivity of 80% at standard interpretation (APHA, 2024)

Badger Trust acknowledges that there is a relatively small amount of bTB spread from badgers to cattle. BCVA quotes Crispell et al, 2015 to demonstrate badger-to-cattle transmission. BCVA again omits to quote more recent government-commissioned research by Akhmetova et al (2023). This paper was also based on genomic testing, but unlike the Crispell study (bizarrely testing badgers in a very small area with an unusually high badger density and testing cattle in a much larger surrounding low density cattle area), the 2023 study tested badgers and cattle in the same area, namely in a 100 square kilometre hotspot in Northern Ireland. Cattle-to-badger transmission hugely outnumbered badger-to-cattle spread, with negligible badger-to-badger transmission. The authors estimate that badger- to-cattle spread was 5.7%, with cattle-to-cattle spread by far the main source of cattle bTB infections, followed by cattle-to-badger spread.  They conclude: 

“The primarily cattle-driven nature of the epidemic in the region, and the comparatively lower impact of inter-species transmission, was again consistent with the findings of Crispell et al., van Tonder et al. and Rossi et al. [19, 21, 22] in other regions where intra-host effects are known to predominate. The absence of any strongly supported badger-to-badger transmission events in TransPhylo, along with the observation that badger landscape genetic structure is not associated with pathogen genetic structure, is suggestive that badgers may not be playing a major role in disease transmission events.”- Akhmetova et al., 2023

Therefore, if badgers are playing a major role in disseminating TB among each other, then closely related badgers could be expected to share more closely related M. bovis. But they do not. This observation on its own is perhaps not as compelling as it could be if observed over a longer time span, but when taken together with the transmission dynamics findings, again the totality of the evidence we present supports the hypothesis of a relatively reduced role for badgers in bTB transmission and persistence in this region, compared to cattle.

“Our BDMM inter-species transmission data contrast with the findings of Crispell et al. 2019 from the Woodchester Park region of Gloucestershire that found badger-to-cattle transitions were much more common than cattle-to-badgers. We find the opposite, albeit with caveats about the precision of estimates as described above…. Such heterogeneity in regional disease epidemiology, both at temporal and spatial scales, may well call for a more heterogeneous approach in the application of disease eradication schemes.” - Akhmetova et al., 2023

It would be good to repeat the Northern Irish research in other areas in England to inform decision making; if indeed cattle-to-badger spread greatly outnumbers infection vice versa, in the absence of any badger-to-badger transmission, tackling the disease in cattle should greatly reduce TB in badgers, therefore even further reducing potential badger-to-cattle transmission risk. Woodchester Park is not representative of badger density in the rest of England and Wales.

BCVA states that culled badgers are necropsied, looking for visible lesions.  Of 102,349 badgers killed under cull licences 2013-2019, just over 900 (< 0.9%) were subject to post mortems and tests for bovine TB, with a tiny minority having visible lesions; this is not implied in the BCVA document. During the 2013 culls all killed badgers were examined to establish the accuracy of the shot, and vets were explicitly forbidden to look for TB lesions—APHA appeared to be worried that the vets might not find many.  Mycobacterial culture is the only way to get accurate infectious results, and we believe APHA should be routinely testing culled badgers and reporting on this.   

BCVA states that they have tried hard to bridge the relationship between private vets (PVS), government vets, farmers, and DEFRA. Farmers represented by the NFU and AHDB, DEFRA staff and most BCVA members have all been heavily promoting the badger culls from the start.  Bridging the gaps between stakeholders with regards to the badger culls cannot have been that hard. Many parties have been colluding to encourage the culls and once you have heavily promoted the badger culls, it might be awkward to admit that perhaps badgers are not the main cause of TB in cattle. There is a notable absence of bridging with any parties representing wildlife: charity, academic or otherwise, despite the culls heavily impacting on the native badger and other wildlife populations.

BCVA worries about the effect of bTB on farmers. Indeed, bTB outbreaks can have a devastating effect on farmers, their stocking rates, finances, mental well-being to name a few. However, many farmers can do more to improve biosecurity and thus reduce risk. Cattle movements are a major source of introducing TB in a herd, but this hasn’t stopped numerous farmers buying in stock, pre-movement tested with a skin test that has poor sensitivity. Even so-called ‘closed herds’ often share machinery, show cattle, go to livestock markets, use contractors and bring in ‘clean’ bulls.  As the documentary showed, these bulls can have repeatedly passed the SICCT test, but be riddled with TB lesions at post-mortem many years later.   Biosecurity between groups on one holding is often non-existent. Biosecurity in cattle is nowhere near the level seen on nucleus or breeding pig units for example. There is plenty of room for improvement, and therefore plenty of opportunity to reduce risk. Genomic testing has demonstrated that many cattle outbreaks previously attributed to wildlife were in fact caused by residual infections in cattle.

And we desperately need better cattle testing, both for surveillance and pre-movement. We need to validate the Mycobacterium bovis PCR test on cattle faeces as soon as possible and streamline sample preparation. We need to encourage the development of antibody testing in milk and bulk milk. BCVA should lobby DEFRA to allow the use of alternative bTB tests without the need for DEFRA’s permission.  In the year to July 2024, after more than 11 years of killing badgers, 21,943 cattle were culled to TB—hardly a resounding success story.

We all strive to control TB in cattle, in badgers, alpacas, deer, sheep and so on. We cannot carry on killing all our native wildlife, just on the off-chance they played a role on a particular farm. The Brian May programme clearly demonstrated cattle that tested clear on the skin test were actually shedding large numbers of M.bovis in their faeces. Perhaps it is time for a fresh approach and take on board any new findings, rather than defending current TB control policy come what may.

Sir Brian May emphasised the absolute need of working together and keeping an open mind — we couldn’t agree more! The Labour government also pledged to work with farmers, scientists and conservationists to develop a TB policy. Perhaps we can discuss a way forward together in the future. 

References

Akhmetova, A., Guerrero, J., McAdam, P., Salvador, L.C., Crispell, J., Lavery, J., Presho, E., Kao, R.R., Biek, R., Menzies, F., & Trimble, N. (2023). Genomic epidemiology of Mycobacterium bovis infection in sympatric badger and cattle populations in Northern Ireland. Microbial Genomics, 9(5), 001023.

APHA (2024). Skin Test. Available from: http://apha.defra.gov.uk/External_OV_Instructions/TB_Instructions/Skin_Test/index.htm [Date Accessed: 16/09/2024]

Birch, C.P., Bakrania, M., Prosser, A., Brown, D., Withenshaw, S.M. & Downs, S.H. (2024). Difference in differences analysis evaluates the effects of the badger control policy on bovine tuberculosis in England. Scientific Reports, 14, 4849.

Crispell, J., Benton, C.H., Balaz, D., De Maio, N., Ahkmetova, A., Allen, A., Biek, R., Presho, E.L., Dale, J., Hewinson, G., & Lycett, S.J. (2019). Combining genomics and epidemiology to analyse bi-directional transmission of Mycobacterium bovis in a multi-host system. eLife, 8, e45833.

Crispell, J., Cassidy, S., Kenny, K., McGrath, G., Warde, S., Cameron, H., Rossi, G., MacWhite, T., White, P.C., Lycett, S., & Kao, R.R. (2020). Mycobacterium bovis genomics reveals transmission of infection between cattle and deer in Ireland. Microbial Genomics, 6(8), e000388.

Doran, P., Carson, J., Costello, E., & More, S.J. (2009). An outbreak of tuberculosis affecting cattle and people on an Irish dairy farm, following the consumption of raw milk. Irish Veterinary Journal, 62, 1–8. 

Downs, S.H., Prosser, A., Ashton, A., Ashfield, S., Brunton, L.A., Brouwer, A., Upton, P., Robertson, A., Donnelly, C.A. & Parry, J.E. (2019). Assessing effects from four years of industry-led badger culling in England on the incidence of bovine tuberculosis in cattle, 2013–2017. Scientific Reports, 9(1), e14666.

Langton, T.E.S., Jones, M.W., & McGill, I. (2022). Analysis of the impacts of badger culling and cattle controls on bovine tuberculosis in cattle in the high risk area of England, 2009-2020. Veterinary Record, 190(6), e1384.

McCallen, L., MacNair, J. & Skuse, R. (2014). An overview of the potential role of cattle slurry in the spread of bovine tuberculosis. Bacteriology Branch Veterinary Sciences Division Agri-food and Biosciences Institute. Available from: https://library2.nics.gov.uk/pdf/dard/2015/EFGP.pdf [Date Accessed: 28th August 2024].

McGill, I. and Jones, M., 2019. Cattle infectivity is driving the bTB epidemic. Veterinary Record, 185(22): 699-700.

Rossi, G., Crispell, J., Brough, T., Lycett, S.J., White, P.C., Allen, A., Ellis, R.J., Gordon, S.V., Harwood, R., Palkopoulou, E., & Presho, E.L. (2022). Phylodynamic analysis of an emergent Mycobacterium bovis outbreak in an area with no previously known wildlife infections. Journal of Applied Ecology, 59(1), 210-222.

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[1] from April 2017 additional mandatory interferon-gamma testing of cattle was introduced to detect and remove infected cattle during OTFW incidents in areas within the High Risk Area that had been in the Badger Cull area for at least two years. Culling licences also required increased biosecurity measures in cull areas.