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


Examination of Witnesses (Questions 420 - 428)

WEDNESDAY 24 OCTOBER 2007

SIR DAVID KING AND PROFESSOR MARK WOOLHOUSE

  Q420  Mr Drew: In terms of the pure practicalities of this, what evidence did you take separately from those who would be tasked to carry out badger removal operations? In particular, what means would need to be applied to achieve even a 70 to 80% level of removal, and did that play any part at all in your conclusions?

  Professor Woolhouse: I am beginning to feel very exposed if you are going to ask me about the procedures under which the Chief Scientific Adviser does his operation.

  Chairman: Do not go beyond what you feel comfortable in answering.

  Q421  Mr Drew: You can just say that you are unhappy with that, but it is an important question that we try and wrestle with, and this goes back to my earlier point about—

  Professor Woolhouse: In terms of the input on the practicalities, we did have present in the meeting for background information the Chief Scientific Adviser for Defra, Sir Howard Dalton, and the Chief Veterinary Officer, Debbie Reynolds, and a number of their colleagues, and they were helpful in commenting on that as a practicality and so on, but that is not within the remit of the scientific group that Sir David assembled.

  Q422  Chairman: Just on one practical point in your report, you comment that the badger population should be "monitored". Did you come to any conclusions as to who should do it and with what frequency? Was it going to be UK-wide monitoring, England, Wales, what? What conclusion did you draw on that?

  Professor Woolhouse: Again, I am not specifically a badger expert, and Rosie Woodroffe can no doubt address this more clearly for you, but there are attempts to survey the population density of badgers from time to time in the UK. The feeling was that if you are going to implement—and it is beyond my remit to say whether you should or not—any kind of badger control you need to be very clear about what you have actually achieved on the ground, for two reasons. One is to understand why you have succeeded, but the second, if things do go wrong, is to understand why you failed, and that is a very important part of trying to assess the performance of any kind of large-scale intervention. That would apply in a lot of different circumstances from controlling TB in badgers. You need to understand what is going on.

  Q423  David Taylor: You say you are reluctant to comment on practical methods of carrying out culling and so on. Do you recall any of the discussion that took place with the Defra people and others there about what would be the most humane and effective means of removing badgers? Do you know what they meant by that or was that referred to in regard to snaring perhaps?

  Professor Woolhouse: Snaring was discussed because, of course, that was one of the methods used in the Irish trials, and my understanding is that that is not felt to be humane and sustainable on a large scale in the UK. You really do need to talk to some animal welfare experts.

  Q424  David Taylor: Do you recall which ones were broadly left as viable options?

  Professor Woolhouse: The one that has already been rejected, as you well know, is gassing, which was rejected some time ago, so we are left with trapping and shooting as the alternatives, as I understand it, but you really need to talk to someone who is expert in these areas.

  Q425  Chairman: Can I just take you back—and I am sorry this is a little bit random but there were a lot of points that came out of your report—to paragraph 46 where you say the following: "This time lag does not seem to have been taken into account when the ISG collected data on cattle TB incidence immediately after the first proactive cull"? You said at the opening of your remarks that you basically came at this subject from the same data as the ISG, implying the analysis was okay, and yet in this particular paragraph you do seem to be hitting them head on about the measurement of the effect in the first year of culling. You say you cannot really read anything until you have done it for two years. That does seem to me to be a challenge in methodology as a layman reading those words. Why did you choose, if you like, to come to that particular conclusion, because obviously it questions the analysis of the effectiveness of culling, does it not?

  Professor Woolhouse: It certainly does not challenge the data or the analysis of the data that they received. It is a question of how much weight you place on the first year's results in an intervention of this kind. There are a number of studies that have shown quite clearly that these sorts of interventions are going to take a number of years before they have their full effects and the Irish trial is a very good example of that. Not only does it take in that case four or five years in order to achieve the full effect they saw at the end of that trial, but, if you like, the way to that final effect is quite noisy. Even in the Irish trial in some years in some sites the incidence of bovine TB in cattle went up as it was going down. These are very stochastic processes. There is a lot of variation in the trajectory, so it is difficult to draw firm conclusions from just one year's data, and that, of course, was one of the difficulties that was highlighted by everyone.

  Chairman: I deliberately picked that because you have made a statement that says it is very difficult to draw conclusions from one year's data, but if I understood the ISG's work correctly (and they can answer) they did put quite a lot of weight on what happened in year one. I suppose one of the factors that we are trying to sieve out is how much you are having a go at the way they interpreted the information, and there does appear to be a difference of opinion about the year one effect, as you have just enunciated. They take a different view. The difficulty for the lay person is whose view is right and how do we decide whose view is right, because it is effectively lay people with the benefit of advice who are going to have to ultimately take the decisions as to what is going to happen to deal with the disease pool which Sir David King, quite rightly, identified as a major problem that had to be dealt with. I am going to leave that as a statement because you may not be able to help us adjudicate and Mr Drew wanted to come in with a further point.

  Q426  Mr Drew: Did you actually read any of the papers around the Thornbury experiment, which obviously was the most comprehensive study of badger removal over a long period of time, even though most of those papers have been destroyed? Do you know about Thornbury?

  Professor Woolhouse: I know of Thornbury. If you are going to start quoting it at me I am going to have to—

  Q427  Mr Drew: It would be interesting to know about that, because if you were coming to that conclusion you would have to look in a sense at what the existing history of culling was in this country, and Thornbury is as close as you can get to some scientific investigation, so did that play any part at all in you coming to the conclusion that you came to?

  Professor Woolhouse: It is not cited in the report, I believe.

  Q428  Mr Drew: No, it is not cited.

  Professor Woolhouse: Although the experts around the table would have been aware of it to some degree, I would not say it was a major contributor. The major contributor, as Sir David has said repeatedly, was the ISG's report and the publications arising from that.

  Chairman: Thank you very much for staying on and answering those additional questions. You are very welcome to stay in whatever capacity you like and listen to the next bit because we did say at the outset that there were some more questions that we wanted to put to John Bourne and his colleagues, but we also wanted to afford them the opportunity of providing us with a commentary if they wanted to. They do not have to if they do not want to but the opportunity now exists for him and his colleagues to say a few words about what they have heard from Sir David King. It might help us as lay people to understand what it is that we have been told, so, Professor Woolhouse, you can either move to the end or go to the back, whichever you feel comfortable with, and we will invite the ISG former members to resume the witness stand.






 
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