Select Committee on Environment, Food and Rural Affairs Minutes of Evidence


Examination of Witnesses (Questions 20 - 39)

MONDAY 18 JUNE 2007

PROFESSOR JOHN BOURNE CBE, PROFESSOR CHRISTL DONNELLY, PROFESSOR JOHN MCINERNEY OBE AND PROFESSOR ROSIE WOODROFFE

  Q20  Mr Williams: Just to take the reasoning of the Chairman a little bit further, as I understand it, the average over the five years or four years was 23% improvement and 25%, but then the actual figures in the fourth or fifth year were 33% less breakdowns and 11% more. It seems to me you are going in the right direction. What we are trying to get to is, is it that the process has not been carried on over a long enough period of time to achieve the most beneficial results?

  Professor Bourne: You are not only considering the time you do it, but that then takes you into the area over which you cull, because you are continually going to get the drain of badgers into the culled area, as Rosie indicated.

  Q21  Mr Williams: The ecology of the badger has been explained but the actual numbers of herds breaking down, which is what we are about, in a way, seems to be improving and going in the right direction.

  Professor Bourne: If you consider the number of cases actually saved, it is still very, very low.

  Q22  Mr Williams: Even per year towards the end of the experiment?

  Professor Bourne: Yes.

  Q23  Mr Williams: Are those figures in your report?

  Professor Woodroffe: After the first cull, if you do the benefit versus the detriment, the detrimental effect in the first year is so huge that in fact if you did proactive culling once, or even twice, your overall outcome is that you just make things worse.

  Q24  Mr Williams: What we are saying is that yes, we understand at the beginning, when you remove a huge part of the population and you get lots of movement of badgers, you do not get very good results in terms of herd breakdown but as you are going on, it improves.

  Professor McInerney: One of the difficulties that you are groping for is: can we extend on from the five-year experience to another five years and another five years? One can, if one is speculative, but it would be a very dangerous thing to do to extend five years' experience into 20 years. The simple answer to your question, Chairman, is, if you can get 25% of TB removed with five years' culling, can you get another 25% so that in 20 years you have got rid of it? My understanding of the ecology is that no, it is not that simple, which is a pity because if it was that clear, one could at least sit down and say, "OK, can we contemplate a 20-year culling programme? Where might we be and might that be worthwhile?" I would tend to shudder at the cost of a 20-year culling programme given the cost of a five-year culling programme but I can see why one would like to feel that the ability to control the disease could be just rolled on from the five years' experience of this cull.

  Q25  Chairman: I ask these questions because among those who will listen and reflect on what is being said, there are those who are entirely with you and those who remain deeply sceptical, and we just have to try and tease out whether in fact the idea of a cumulative policy has any merit.

  Professor Bourne: There are other important caveats to this culling programme and those are that the culling is done sequentially on an annual basis by professional teams over a very, very long period. You may wish us to comment further on the professionalism required, particularly in relation to land access and also the level of trapping efficiency that you might expect to get.

  Professor Woodroffe: The level of effort that this took was in the region of 40 trap nights per square kilometre per year for five years, but the way that the trapping was done was not just that you sling out some traps and wait. Bear in mind that not every land holder provided consent to cull. In order to achieve the most effective culling success that we could, traps were deployed around areas of inaccessible land to try to achieve the best removal that we could, including areas that were inaccessible for trapping. That was successful and we were able to show that by culling around those, in patches of accessible land we were able to suck the badgers out, but that sort of process requires a great deal of experience in badger natural history and behaviour, recognising field signs and so on. It is something that professional staff are needed to do. The level of success that we achieved is shown in various different measures: the density of badger field signs, various different measures of badger activity in proactive areas was about 70% lower in the proactive areas towards the end of the trial relative to the areas that were not culled, and bearing in mind this substantial evidence of immigration of badgers into the area, that suggests we are catching more than 70% of them each time, it is just that more keep immigrating. So our trapping efficiency is probably upwards of 80%, I would estimate, on that basis. We have been criticised for having not removed enough of the badgers but a lot of those badgers that are there are ones that came in from outside and we have genetic evidence in support of that.

  Professor McInerney: Even if you did go on for five years and five years and five years, at the end of it you would only have managed to eliminate the badger element of TB, and since we do not know exactly how much that would be or how that might change over time, it is very difficult to predict therefore what the TB occurrence would be at the end of a long and extended culling programme.

  Q26  Dan Rogerson: We are saying that it is possible potentially to have an impact through quite a large-scale cull in an area but the problem is that it is re-populated. In an area such as, for example, a peninsular, might it be possible to look at what happens if you were looking at tougher measures of controlling it in the herd and also some form of cull in an area that is quite well geographically defined?

  Professor Woodroffe: Yes, we can speak directly to that because one of our trial areas was West Cornwall, the Penwith Peninsula, but we had a variety of different trial areas with different permeability of the boundaries to badgers. The extent to which badgers can immigrate into an area certainly influences the course of infection in the badger population over successive culls, so each time you cull the badgers across all the different trial areas, you see on average that the prevalence of infection in badgers goes up. So each time you cull, the prevalence is higher and higher and higher, to the extent that by the fourth cull the prevalence in the badgers has roughly doubled and that is to do with mixing of the badgers, breakdown of the social organisation, which causes disease to spread. What we see is that that effect is influenced by this boundary permeability, so in the badgers we see that places like West Penwith, the prevalence in the badgers actually did not rise; it remained roughly constant. So you are really successfully there forcing down the density of infected badgers. Unfortunately, when we looked for a similar effect on the impact of culling on the incidence of TB in cattle, we were not able to detect any effect.

  Professor Donnelly: The difficulty, of course, is it was not set up to be able to distinguish within these groups of ten comparisons, so certainly we would expect on the basis of the mechanism that we believe is taking place that it is extrapolation on that basis rather than what we have been able to estimate from the data.

  Q27  Dan Rogerson: So it is possible, and farmers in a place like Cornwall who would want to perhaps co-operate in some form of action of this nature, that if measures were taken to deal with it within the herd as well, the testing programme and so on, that some form of a generalised control—

  Professor Woodroffe: I would make two comments on that. One is that if we stick with that specific example, which is an area I know well, being from there, that actually of all the areas where we worked in the course of the trial, Triplet F, the West Penwith proactive area, had the lowest land owner consent, far and away; half the area was accessible to us, so if that was the place that we considered the best, that would probably offset the benefits for an area like that. One point to which this is highly relevant is comparison with results from the Republic of Ireland, where there has been a great deal of discussion and speculation over the application of the Irish findings to ours. Of course, one of the key differences between our trial and the trial that was conducted in the Republic of Ireland was that, whereas we chose representative areas of high TB risk to cattle, in setting up the Irish study they chose the areas where they thought that culling was going to work best, and they deliberately chose the four places in Ireland where they could find places with these sort of geographical barriers to badger immigration, and where they could not find barriers like that, they had very substantial areas which they culled but from which they never reported the incidence of cattle TB. What I think that means is, I suspect it is probably the case that those sorts of geographical boundaries might well be expected to influence the impact of badger culling on cattle TB incidence and perhaps a comparison with Ireland might lend support to that. There are very few places in Britain that have those sorts of geographical barriers, so whilst it might be something that is locally potentially of some value, in terms of national TB control it is probably not that useful.

  Professor Bourne: You mentioned Ireland. I think there are other issues there which are important in comparing the Irish situation with the one in this country. They certainly have a much lower badger population than we do. In tackling their badger culling they, of course, used snaring and have less welfare considerations than we were forced to give to the trapping that we carried out in the trial. Very importantly, they had 100% farmer co-operation and we did not get that. Defra could not find out who owned 13% of the land area in our trial area, in spite of the resource they have to try and resolve that issue. 13% of the land over here just was untrappable in that sense. The other thing is that there is no badger group in Ireland. The social attitude to the badger over there is totally different to social attitudes here.

  Q28  Chairman: We are going to come on to Ireland in a little while. Just on a point of methodology, you have made it very clear to us that peer review—in other words, you are not coming under flak from scientists that in some way your analysis and its conclusions were flawed, but you have just made the point that you had at least half a hand tied behind your back because you could not get 100% land owner co-operation, and you made that point of contrast in relation to the Irish trials. I suppose it is an impossible question to answer but nonetheless, I might ask it: if you had had, were there examples within all of the trials that you did where you got 100% land owner co-operation and, if so, were there any significant differences between the lower order where you did not get that co-operation and those areas where you got a higher percentage of co-operation?

  Professor Donnelly: There certainly were no areas with 100% coverage but what we did find was we divided up in further analyses—and this is part of the IJID paper that was just published. We actually looked at farms that were on accessible land versus farms that were on inaccessible land and we did not find a significant difference between them. In fact, the non-significant difference was in the opposite direction to what you would expect, so what we found was that those farms on accessible land actually did slightly worse than on inaccessible. There was nothing in the statistics to show that the benefits were different. The explanation for that is that actually, the vast majority of areas of inaccessible land were very small. So while we had direct access to about 70% of the land area, traps were deliberately placed on the boundaries and about 70% of the remaining land was within 200 metres of accessible land.

  Professor Woodroffe: Which is well within the ordinary daily ranging behaviour of badgers. On successive culls we were clearly sucking more and more badgers out from those areas of inaccessible land, so we were pretty convinced that we were removing substantial numbers of badgers from those little pockets of inaccessible land, even though we could not place traps on that land.

  Professor Donnelly: We showed that per square kilometre in the little strips just around the inaccessible land on subsequent culls we actually took out more badgers per square kilometre than on the remainder of the accessible land.

  Professor Bourne: It did require trapping expertise to achieve that, of course.

  Q29  Mr Cox: I am in danger here of getting into territory that we may explore later but, as I understand your report—help me if I am wrong, Professor Bourne -you have consistently said in this report that though as an instrument of general national policy you take the view that culling is not a cost-effective or sustainable policy, it may be—and I am looking here at number 8 of your general conclusions—that areas with boundaries impermeable to badgers could contribute to TB control on a local scale, although you make the point that, of course, such areas in England are relatively few.

  Professor Bourne: There we were referring actually to the odd farm that does build badger-proof boundaries. I am aware that some of these farms do exist in the South West. We recognise that they are expensive and we recognise that although they might make a contribution to that farm, they make no contribution to the national impact.

  Q30  Mr Cox: Can we also look at paragraph 5.16 at page 90 of your report, where you deal specifically with the impact of permeability of trial area boundaries. What you seem to conclude there is that your trial, scientifically speaking, can really shed very little light—indeed, you say "currently available data shed no direct light on whether a proactive culling policy would be more beneficial if conducted in more geographically isolated areas". It follows from that report, if one can take the black and white letters, that in areas which may be geographically isolated or may be otherwise able to be impermeable to the immigration effect, that it is conceivable—and Ireland would seem to support that—that culling might be beneficial.

  Professor Woodroffe: Yes. You are absolutely right to pick up the difference between page 90 and page 20 whatever it is, and that is an extrapolation. Within the areas that we actually studied we found no impact of boundary permeability on the effect on cattle, bearing in mind that most of the trial areas had areas that were considered to be 100% permeable to badger immigration.

  Q31  Mr Cox: But you had no evidence either way. That is the point.

  Professor Woodroffe: We could not detect any effect, but we were able to detect an effect on the badgers themselves and we were able to show that you did not get this rise in the prevalence among the badgers in badger TB prevalence in these areas the badgers could not easily re-colonise, and it was on the basis of that that we extrapolated to suggest that perhaps therefore, if you were to expect culling to work anywhere, that would be where you would expect it, but we have not detected ourselves in the trial an effect of barrier permeability on TB incidence in cattle.

  Q32  Mr Cox: Professor Woodroffe, forgive me, but the report says it sheds no light on whether a proactive culling policy would be more beneficial if conducted in more geographically isolated areas. The conclusion that that states is either way: it might be, it might not be.

  Professor Woodroffe: It might be or it might not be. Exactly.

  Q33  Mr Drew: Can we move on to policy? Professor Bourne, it would be interesting to know if you have had a discussion with Ministers since the report has been made available?

  Professor Bourne: No.

  Q34  Mr Drew: So you have not met Ministers?

  Professor Bourne: No. I last met Ministers on 1 February.

  Q35  Mr Drew: Can we move on then to looking at how the Government may come to its policy evolution. When you were interviewed this morning on Farming Today, you were somewhat querulous about how Defra were going to handle the scientific data and then subsequently translate it into policy, given that you felt they did not have a good track record with their attempts to draw up their consultation document. Is there any discussion on how you might help them with that, given that you have not talked to Ministers, but presumably you have talk to officials about how they might be wanting to take policy forward?

  Professor Bourne: We have not directly had these discussions, no. I certainly have had more discussions with the scientific expertise within Defra based at VLA and CSL and recognise the quality of that expertise, and I think the frustration they experience in not having adequate opportunity at extending science into practice. You mentioned the consultation exercise. That was just one indicator.

  Q36  Mr Drew: It was a fairly important one.

  Professor Bourne: Yes. There was an even more important one, and that relates to the discussions we had with Defra in 2001 on work to develop the gamma interferon test. It was apparent at that time that future policy would demand improved diagnostic tests. We discussed with Defra ways in which field data could be gathered to provide information to inform on a range of policy options, and they rejected our proposals and went ahead with a pilot trial on the grounds that they could not afford to do anything else, and you know the outcome of the pilot trial. It did provide some very informative data but it did not inform scientifically in the way one would have hoped. We have advised that there has to be a closer working relationship with scientists, particularly in Defra, to ensure that appropriate data is collected to inform on future policy options. Also, that data available from the testing of animals is regularly interrogated with a clear strategic view as to what that data might tell them and how that in turn can be implemented into policy in a way that we have called adaptive management, which really means extending scientific findings into the policy of disease control. We have not seen signs that that has happened and we believe it is critically important that it should. Equally, we have stressed—and I think this is a very important recommendation of the report—that Defra should develop a very clear strategy. At the moment it would claim it does have a strategy, the strategy of reducing the incidence of disease in high-risk areas and preventing its geographical spread, but what are the details of that strategy? It has not really been thought out. I believe there should be a clear strategy of what they want to achieve, what is achievable, what resources are necessary to do that, and this should be driven by a focus group involving scientifically informed individuals driving that, certainly with farmer input because they are important stakeholders, and in that way develop a strategy, sell that strategy to stakeholders and drive it forward in a way that one sets targets and knows where one is going. That would in turn require that the whole thing is costed. I am not aware that Defra have ever costed any policy and determined how the policy can be matched to cost. They have certainly borne the increasing cost of compensation payments but that is not the same as what we are proposing. These are the elements of our proposals which relate to data collection, rigorous and ongoing data analysis and interrogation, and how one uses that to feed into a strategy that has already been focused and you have a group driving it. I do not see the mechanisms within Defra at the moment to do that.

  Q37  Mr Drew: What has been your response to ministerial statements, written and oral, that have come out since your report has been published?

  Professor Bourne: I was aware of Mr Miliband's statement this morning. I am not aware of any others.

  Q38  Mr Drew: What is your response to that? It is fairly anodyne.

  Professor Bourne: It does not say anything. If I were a badger welfarist, I would see something there for me and if I were a farmer I would see something there for me but really it did not say anything.

  Q39  Mr Drew: In the weeks leading up to the publication we have had everybody spinning against everybody else.

  Professor Bourne: That has happened for the last ten years.


 
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