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 an 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.
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.
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.
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.
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].
My own position has long been that I don’t like the idea of a Badger cull but if it can be done affectively 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…