Loading ...Bovine TB and Badgers – the debate grinds on – part 1
The debate over transmission of bovine TB from badgers to cattle in rural areas has been long standing, with very strong opinions on both sides.
Farmers and the agriculture industry wish to protect cattle from bTB (bovine terbuculosis), known to be carried by badgers (the first infected badger discovered was in 1971, with the spread now doubling every 4.5 years) but of course wildlife enthusiasts are not willing to allow these wild animals to be killed without strong scientific evidence that culling will significantly prevent the spread of the disease or an alternative method of control found.
This week FWi reported that DEFRA Secretary Hilary Benn has asked for more time to consider the “complex issue” of badger culling, which led me to consider the issue in more detail.
I have never been sure where I stand on this issue, having sat in a farmhouse tensely waiting for the results of testing to say whether our herd would be slaughtered but also being a wildlife lover that believes evidence must be put forward before we start a programme of killing wildlife. So I have just spent a number of days reading everything I could find on the subject.
If you are also unsure of what evidence and methods of control are currently available then you may this find this an interesting read. There is so much to be considered that I shall continue posting about the topic over the coming week.
The story so far …. in 1996, Professor John Krebs and a review team published a report stating that “the sum of evidence strongly supports the view that, in Britain, badgers are a significant source of infection in cattle” but scientific data was lacking and a randomised badger culling trial (RBCT) should be set up to collect data.
Enter the ISG (Independent Scientific Group on Cattle TB), who then spent ten years studying this issue and using randomised culling in thirty areas to establish scientific data. The ISG Final Report was issued on 18 June 2007, in which the Chairman Professor Bourne concludes “After careful consideration of all the RBCT and other data presented in this report, including an economic assessment, we conclude that badger culling cannot meaningfully contribute to the future control of cattle TB in Britain”.
Defra then passed the report on to Sir David King, the governments Chief Scientific Adviser, for assessment. Sir David King then considered the report, along with five experts but without the knowledge of ISG or discussing with them their years of research. They reviewed the ISG reports for a number of weeks and then met for a single day. His report Bovine Tuberculosis in Cattle and Badgers was finalised on 30 July 2007 and makes interesting reading, as much for his very different conclusions to those of ISG as for his findings.
Sir King’s report concludes “In our view a programme for the removal of badgers could make a significant contribution to the control of cattle TB in those areas of England where there is a high and persistent incidence of TB in cattle, provided removal takes places alongside an effective programme of cattle controls.”
What we do know is that the ISG reports that proactive badger culling reduces TB breakouts in cattle herds by 23% and Sir Kings report states that a 27% reduction can be achieved because the first year ISG results should be omitted. However, culling creates migration of badgers and therefore breakouts of infection were reported outside the cull zone, with ISG reporting a 25% increase in breakouts outside the zone and Sir King reporting 20% (due to the first year results issue). In real terms this means that over a 5 year period of culling in ten 100km square areas 14 breakouts would be prevented.
The other alternative is reactive culling (ie culling where and when an outbreak occurs), however this is known to cause a 27% increase in outbreaks in the surrounding area.
So why the big differences in conclusions in these two reports? The ISG suggested that it was neither practical nor economically feasible to carry out culling on a level that would have a significant effect. Whereas Sir Kings report did not consider practicality or economic issues, dealing solely with the question of whether in theory a badger cull could have a significant impact on the spread of the disease in cattle.
You can find all of the Defra information on bovine TB here but the page has not been updated since Oct 2007.
In the next post we will look at what the Badger Trust has to say about all of this.
The remaining posts in this series can be found here:
Bovine TB and Badgers – the debate grinds on part 2
Bovine TB and Badgers – the debate grinds on part 3
Bovine TB and Badgers – the debate grinds – conclusion
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