On Friday a new scientific analysis of the effectiveness of Badger culls on reducing bovine tuberculosis in cattle was published. I knew this paper was coming and knew that it would be greeted with acclaim by those who oppose the cull and derision by those who support it, and that has largely been true.
The trouble is, that most people in both groups won’t actually understand the science behind the study. They are reacting to the message on some level that ignores the science completely. You have a read of the paper and see whether you regard yourself as qualified to assess its validity. Nip off now and have a read – click here.
How did you do? How good is your understanding of Bayesian and frequentist approaches? No, mine is completely lacking too. I reckon I have a loose grasp of what the authors have done, but no deep understanding, and therefore strangely enough, no real view, on whether they have done it really well or really badly.
The results, summarised in the paper, are:
Analyses based on Defra published data using a variety of statistical methodologies did not suggest that badger culling affected herd bTB incidence or prevalence over the study period. In 9 of 10 counties, bTB incidence peaked and began to fall before badger culling commenced.
https://bvajournals.onlinelibrary.wiley.com/doi/full/10.1002/vetr.1384
And the conclusions are clear too:
This examination of government data obtained over a wide area and a long time period failed to identify a meaningful effect of badger culling on bTB in English cattle herds. These findings may have implications for the use of badger culling in current and future bTB control policy.
https://bvajournals.onlinelibrary.wiley.com/doi/full/10.1002/vetr.1384
I think this is pretty telling too;
During the same period as this study (2009–2020), Wales achieved similar reductions in herd bTB incidence as England, through the introduction of improved bTB testing and other cattle measures, and without widespread badger culling. This suggests that bTB in cattle can indeed be controlled through cattle measures alone, as was predicted by the Independent Scientific Group in 2007.
https://bvajournals.onlinelibrary.wiley.com/doi/full/10.1002/vetr.1384
I’m kind of rooting for these results being right, as I rather hope that we can end mass-culls of native wildlife soon. But I can’t tell you whether the paper’s conclusions are well-based on the science or not. At the moment I am largely taking them on trust because this doesn’t look like a trivial piece of work, it is published in a reputable journal and it wouldn’t surprise me at all if it were completely correct given previous published studies which I understand better than this one.
You can find media coverage of the study as follows; BBC, Daily Mail, Independent, The Times but nothing at all in The Guardian as far as I can find (how bizarre). See also this piece and this piece in the Veterinary Record itself.
You’ll see that DEFRA has attacked the study in very strong language, even The Times describes DEFRA’s reaction as ‘an outspoken attack on the scientists’ which it is, as DEFRA say that:
This paper has been produced to fit a clear campaign agenda and manipulates data in a way that makes it impossible to see the actual effects of badger culling on reducing TB rates. It is disappointing to see it published in a scientific journal.
That comes pretty close to playing the men and not the ball, and it might be correct, but it certainly doesn’t come from a disinterested party given that DEFRA has spent over £100m of our money, and killed over 100,000 Badgers in a state-sponsored, Natural England-licensed cull of a native mammal. DEFRA doesn’t look like an objective player in this game to me – one could easily believe that they have their own competing campaign agenda. The DEFRA blog on the study is highly intemperate too, blaming the authors, the journal and the media for reporting it! The Veterinary Record publishes what DEFRA calls a rebuttal but what could also be described as a critique of the new study (from the DEFRA Chief Vet and DEFRA Chief Scientist) which doesn’t go anything like as far as the DEFRA Press Office did and acknowledges that:
We agree with the authors that OTFw incidence is declining across the HRA and that increased controls on cattle movements, testing and biosecurity will have contributed to this success.
https://bvajournals.onlinelibrary.wiley.com/doi/epdf/10.1002/vetr.1605
That view has almost been forced on DEFRA during the expensive cull by reports such as the Godfray report which said, amongst other things which may have been unwelcome to DEFRA;
…it is wrong, we believe, to over-emphasise the role of wildlife and so avoid the need for the industry to take measures that have in the short-term negative financial consequences [for the farming industry].
https://www.gov.uk/government/publications/a-strategy-for-achieving-bovine-tuberculosis-free-status-for-england-2018-review/bovine-tb-strategy-review-summary-and-conclusions
My own position has long been that I don’t like the idea of a Badger cull but if it can be done effectively to reduce bTB, and humanely, then I suppose I would have to put up with it but that the government needed to give much greater emphasis to other measures, the other measures unpopular with farmers, too. My view hasn’t changed but I am, I bet like you are, a bit confused on what the science truly says on this subject.
I am so glad that DEFRA wasn’t in charge of our response to covid. Vaccination and social distancing, otherwise known in bTB as vaccination, biosecurity and cattle movement restrictions are pretty sensible. I notice that test and trace hasn’t been very successful in bTB terms…
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You are right, DEFRA are in no way neutral. Does anyone else long for the days when we expected politicians and government departments to be objective and honest? Even hoped for it? When lots of government functions were QUANGOs – quasi-AUTONOMOUS functions – i.e. objective and fair, not forced into double-speak to support a part political agenda.
What future is there for society if it isn’t honest? Nothing else will work without that.
I don’t understand this paper either But doubt very much if the hyperbole from DEFRA is based on the science more that it , if correct, badly holes DEFRA’s chosen policy. I never thought the science originally clearly supported a cull and would have liked to have seen a number of measures first based on better biosecurity, more control of cattle movement, better testing and indeed a better test. However we are where we are still killing badgers and still with bTB. It is called bTB for a reason bovine not badger TB. DEFRA are not honest brokers in this being very pro the farming view rather than dispassionately scientific. It is a vested interest mess ( a bit like brood meddling!) that we need a clear way out of for the sake of the farmers, cattle and badgers but I doubt that DEFRA are up to the job.
Despite Rev Bayes developing his Theorem in the 1700s no one took much notice and despite being learned how to perform AoV using either pencil and paper or a clattering Facit machine no-one ever mentioned him to me. His name was being muttered in the late 80s when we were still using black screens and green words and MSDOS and I would have found Bayesian analysis useful for supporting stuff that wouldn’t quite reach the weird artibitrary p=0.05 but was OK at p=0.10.
Perhaps it would be more productive to look at the Why of bTB control rather than the How. Poor Geronimo was separated from his Breath not primarily because he had bTB but because he had reacted to the tests for it. Lesion tissue analysis after autopsy failed to culture M bovis so although bTB infection was not ruled out absolutely, the cause of death was a captive bolt fired by a State employee.
I’ve never seen alpaca meat in Waitrose, even the sort ethically killed by a barefoot hunter using a lead-free flint-tipped spear, so this entire sordid episode comes about “in order to support high standards of animal health and welfare, to promote sustainable beef and dairy sectors, to meet … trade requirements … and maintain public confidence in the safety of products entering the food chain … meet UK international … and domestic legal commitments and maintain the UK’s reputation for safe and high quality food … securing opportunities for international trade”
There are health implications for humans, obviously, although TB is relatively difficult to catch – unless you travel to places where it is frequent and return to live in a hermetically sealed house but no-one in their right mind would do that – but we can and do use milk that has been pasteurised and eat meat from culled positive reactors. The issue, it seems, is that the produce can’t be exported and it is international trade that is being protected. It’s too simplistic to say that this could be stopped – the food supply chain is fiendishly complicated and the employment implications widespread. Unfortunately to listen to a presentation on this for enlightenment is like taking aural Mogadon. But we do need a better justification for killing animals prematurely that have consumed a lot of resources for no reason other than they have failed a test with a disturbing frequency of false positives and are therefore only good enough for us to eat but which are unacceptable to foreigners.
I won’t be holding my breath for an honest debate – it’s never been done before, on any topic, not even in the Golden Age of Honest Debate that never happened.
Is it also worth pointing out that when it comes to disease control the plant industry is much better perhaps because they do not get compensation for stuff that needs to be destroyed.
The taxpayer has carried the risk for livestock and poultry disease for decades. This covers the costs of compensation, surveillance and the costs of clean up. All of it comes out of general taxation. For notifiable plant disease (and diseases of aquaculture) only diagnosis is covered.
Nope, the plant industry and its regulation is a chocolate teapot. The regulation is deliberately lax to avoid commercial costs and “loss of confidence”. The country is being ravaged by imported air-bourne plant diseases that could have been avoided through reasonable control.
I completely agree with your approach Mark. Bovine TB is not nice for cattle. However as I recall the last Labour Government had great doubts as to whether badger culling would be effective and in the end they did not give the go ahead for it.
The science is very important but the proof of the pudding is in the eating and besides the science the report is indicating that in fact the culling is having little or no effect on the disease. This being so, it should be halted immediately.
However unfortunately I think this is unlikely as this Government pays little or no regard to science and actuality . It is driven entirely by its prejudice and politics of its right wing supporters such as the NFU and major farming combines. These organisations will swear blind whatever the science says that culling is what is needed.
So I am sorry to say this awful Government are likely to carrying on this very nasty culling practice. However at least Wild Justice makes it stop and think.
Well done Wild Justice.
This is how research studies should proceed: expert scientists evaluate previous published knowledge in their field and design projects to add to the existing body of knowledge. They then seek funding and ethical approval for their project. On completion of the project, eyeballing the data gives preliminary conclusions, but analysis to determine significance should be performed by independent expert statisticians. The peer review process should include further validation of the statistics. Whilst most of us do not understand the statistics, especially that given in the supporting information, we can have confidence that the above process was followed assiduously in Langton et al. But not by APHA.