Bovine TB: The Independent Scientific Group on Cattle TB: Minutes of the 4th open meeting, 19th June 2007
Speakers
Professor John Bourne (ISG Chairman)
Professor Christl Donnelly
Professor Sir David Cox
Professor George Gettinby
Professor John McInerney
Professor Ivan Morrison
Professor Rosie Woodroffe
Secretariat (Defra)
Mr Mike Summerskill (ISG Secretary)
Dr Alan Patey (Meeting record)
Ms Joy Emonfomwan (Meeting organisation)
ISG Research Assistants
Mr Peter Gilks, Ms Helen Jenkins, Dr Tom Johnston, Dr Andrea Le Fevre, Dr Gao Wei.
Organisations that attended the Meeting (one or more representatives):
Agri-food & Biosciences Institute
Badger Trust
British Cattle Veterinary Association
British Charolais Cattle Association
British Deer Farmers Association
British Livestock Genetics Consortium Limited
British Veterinary Association
British Wildlife Management
Cardiff University
Central Association of Agricultural Valuers
Cliffe Veterinary Group
Country Land & Business Association
Deer Initiative
EFRA Committee House of Commons
Entangled Science
Farm Crisis Network
Holstein UK
Husbandry Working Group
Immunobiology Limited
Institute for Animal Health
Mammal Society
Meat and Livestock Commission
National Beef Association
National Farmers Union
Natural England
Royal Society for Prevention of Cruelty to Animals
Royal Society for Protection of Birds
Royal Veterinary College
Royal College of Veterinary Surgeons
Secret World Wildlife Rescue
School of Tropical Diseases
Science Advisory Council
Soil Association
TB Advisory Group
Tenant Farmers Association
Veterinary Association for Wildlife Management
Veterinary Vaccines Consultancy
Wildlife and Countryside Link
Wildlife Trust
Attendees from the Press:
BBC Farming Today
Farmers Guardian
Farmers Weekly
Veterinary Record
Government Officials, other than those above:
Defra - 26
Other Departments - 6
Attendees who applied as individuals: 10
Total number of delegates: 130
1. Introduction and presentation by the chairman
1.1 The Chairman welcomed all present to the fourth Open Meeting of the Independent Scientific Group on Cattle TB (ISG).
1.2 The Chairman outlined the format for the Meeting. In the morning session there would be presentations from all six ISG Members describing the evidence presented in the Group’s Final Report. In the afternoon session badger control policy options would be discussed by Professor Woodroffe and cattle policy control options would be discussed by Professor Morrison. Then there would be time for a general question and answer session, when he and the other Members of the ISG would respond to scientific questions relating to their work and Final Report.
1.3 The Chairman said that at the outset of the Group’s work in 1998 there was no dependable scientific base on which Government could build their bovine tuberculosis control policy. Results of the Randomised Badger Culling Trial (RBCT) and the other research of the Group, such as the TB99 and CCS2005 epidemiological surveys, now provided the required base which had been obtained by utilising the best scientific practice. For all the Group’s work, clear objectives and protocols were established at the outset; every important aspect had been independently audited and the research described in their Final Report had also been peer-reviewed and published, or shortly would appear, in leading scientific journals.
1.4 The Chairman said that during the progress of the RBCT there had been much mis-placed criticism regarding trapping success. Trapping efficiency of about 80% had been achieved on average, consistent with design expectations; allowing for subsequent immigration this meant that the badger population had been reduced by about 70% overall and sustained at this lowered level over the period of the trial. Regarding interference by activists, only 7% of trapping opportunities had been lost and this had no impact on the outcome of the RBCT.
1.5 The Chairman said that the following six presentations would describe the majority of the Group’s endeavours during the last decade, but their main conclusion was that badger population control, for whatever reason it was adopted, would not contribute to cattle TB control, and might make the cattle TB situation worse, and that cattle TB control as currently applied was inadequate. Heightened cattle control measures would reverse the increasing incidence of the disease and arrest its further geographical spread.
2. Presentation 1
2.1 Professor Woodroffe gave a presentation entitled “The ecology and epidemiology of badger TB” 
(2.62 MB - Please note this is a very large file)
2.2 The conclusions of the presentation were that badger population densities were substantially reduced inside proactive culling areas, and slightly reduced in neighbouring areas, and in reactive areas. Badgers ranged more widely everywhere they were exposed to culling. Where badgers ranged more widely, their TB infections were more prevalent and more widely distributed in space. TB infections in badgers and cattle were spatially associated. Both badger-to-cattle and cattle-to-badger transmission might contribute to this association.
3. Presentation 2
3.1 Professor Donnelly gave a presentation entitled “Trial outcomes: effects of culling on TB incidence in cattle” (1.21 MB - Please note this is a large file)
3.2 The conclusions of the presentation were that in proactive areas (where badger numbers were substantially reduced and ranging was expanded) cattle infection was less prevalent, but remained clustered. For land neighbouring proactive areas (where badger numbers were slightly reduced) cattle infection was more prevalent and became less clustered. For reactive areas (where badger numbers were slightly reduced, badger ranging expanded, and badger infection was more prevalent) cattle infection was more prevalent but became less clustered. Results were highly consistent, both internally and in comparison with other studies. The findings provided a very reliable indication of the likely effects of badger culling on cattle TB, if conducted using similar methods in TB-affected regions of the British countryside. Badger culling, as conducted in the RBCT, could prompt both beneficial and detrimental effects; this severely constrained its ability to contribute to the control of cattle TB.
4. Presentation 3.
4.1 Professor Gettinby gave a presentation entitled “Analysis of farm level risk factors” (184 KB)
4.2 Bearing in mind that the case control approach only identified factors associated with herd breakdowns (not necessarily the same as factors that caused breakdowns) the conclusions of the presentation were that there was evidence of some consistency across the TB99 and CCS2005 studies that increased risk of TB on farms was associated with covered yard housing, multiple farm premises, moving stock on and off and mixed deciduous woodland. There was decreased risk for use of fertilisers, use of manure, cattle movements and pasture meadow. Although the risk of infection could be reduced by taking account of these factors, there did not seem to be a universal solution for farm management to reduce the risk of a herd suffering a TB breakdown.
5. Presentation 4.
5.1 Professor Morrison gave a presentation entitled “The disease in cattle” (242 KB)
5.2 The conclusions of the presentation were that significant numbers of infected cattle remained undetected by tuberculin testing and that these animals represented an important reservoir for transmission of infection and spread through cattle movement. Cattle movement was likely to be responsible for a significant proportion of herd breakdowns. The frequency and pattern of herd testing in low risk areas was inadequate for early detection of new foci of infection. Application of more rigorous cattle control measures could reverse the year-on-year increase in TB incidence and halt the geographical spread.
6. Presentaion 5.
6.1 Professor McInerney gave a presentation entitled “Economic aspects of badger culling” (61 KB)
6.2 The conclusions of the presentation were that in principle a full cost benefit analysis should be conducted to assess the overall economic merits of any TB control policy. However, the Group's calculations had shown that, based on the results achievable as revealed in the trial, there was no economic justification for badger culling as a method of controlling cattle TB as the costs far exceeded the economic benefits in terms of reduced TB breakdowns. The few formal cost benefit analyses that had been done in the past all came to a similar conclusion. It would be difficult to envisage circumstances where badger culling would be an economically defensible approach.
7. Presentation 6.
7.1 Professor Sir David Cox gave a presentation entitled “Why mathematical models?” (43 KB)
7.2 The presentation focussed on “net reproduction number” which was the ratio of disease effective propagation rate to disease removal rate. If this was greater than unity, an epidemic grows, if less than the epidemic dies away.
7.3 The conclusions of the presentation were that by enhancing test sensitivity and by further rigid movement controls the predicted net reproduction number would fall below unity with the consequence that there would be a steady decline in breakdown rate.
8. Presentation 7.
8.1 Professor Woodroffe gave a presentation entitled “Recommendations - policy options involving badger management” (1 MB)
8.2 The conclusions of the presentation were that insights from the RBCT and other studies allowed evaluation of a range of potential badger management options. Neither reactive or proactive culling as conducted in the RBCT could reduce cattle TB incidence sufficiently to contribute to disease control. Careful appraisal of scientific data indicated that no other approach to badger culling was likely to contribute to the future control of TB in cattle in Britain. For this reason the Group recommended that future control strategies should focus on measures other than badger culling.
9. Presentation 8.
9.1 Professor Morrison gave a presentation entitled “Recommendations – control measures directed at cattle” (77 KB)
9.2 The conclusions of the presentation were that in low risk areas the objective should be to prevent further geographical spread and eliminate the disease. There should be stricter cattle movement controls, the combined use of the skin and gamma interferon tests, slaughter of herds with persistent infection and shorter interval testing. In high risk areas control measures should be proportionate, recognising that elimination of the disease from cattle could not be achieved in anything other than the long term. Control measures would aim to reduce the overall level of infection and transmission of infection between herds, but applied to allow farms to continue trading with minimum disruption. Improvements should be made in the quality control of tuberculin testing and follow-up test intervals should be reduced. Regarding the gamma interferon test, there should be on-going analysis of performance under field conditions and an investment in infrastructure to allow automation and high throughput. Genotyping should be incorporated into policy for tracing sources of infection.
10. Q & A Session.
10.1 During the Meeting and at the formal Q&A session at the end of the Meeting, the Chairman and ISG Members answered questions from the audience. These covered the following issues: could badger culling be an effective strategy in areas with defined boundaries (such as coastal areas); the Thornbury trial; effects of culling whole social groups; efficiency of culling; cattle infection rates; the rôle of “super-excretor” badgers; how confirmed and un-confirmed breakdowns were treated by the RBCT statisticians; how were TB99 control farms assessed if these subsequently became a breakdown; in the epidemiological surveys, were totally closed herds analysed, and were farm size and land use taken into consideration in the analyses; the definition of covered yard housing; how was bovine TB virtually eliminated in the 1960s; were cattle genetic factors important in TB susceptibility; in 3-4 year testing areas, did the skin test work differently than in other areas; potential for gassing badgers; risks of contracting bovine TB on farms; use of spoligotype analysis; who should pay for increased cattle controls and should a cost-benefit analysis be undertaken; persistence of infection in herds; numbers of badgers in GB and badgers as predators; possibilities for live TB testing of badgers.
11.1 The Chairman thanked those present for attending the Meeting and said that he hoped that the presentations and the answers given to the questions posed had been enlightening.
11.2 The Chairman acknowledged the help given to the Group, and without which their work could not have been completed, by a large number of individuals and organisations, but especially by the farmers and landowners in the RBCT areas, Defra’s Wildlife Unit and CSL/VLA Agencies, the ISG Research Assistants and Secretariat, and the many international scientific collaborators.
11.3 The Chairman ended his acknowledgements by saying it had been a privilege to work so closely with the other Members of the ISG and he would remain ever-grateful to these highly gifted scientists of international standing, who had given unstintingly of their time. Their commitment had ensured the well being of this project.
12.1 Professor Chris Gaskell of the Science Advisory Council offered a vote of thanks to the Chairman and the Group.
ISG Secretariat
July 2007
Appendix
Fifth and final open meeting: 21 June 2007
1. The ISG held its fifth and final Open Meeting in Cardiff on 21 June 2007, as guests of the Welsh Assembly Government.
2. The format of the Meeting and the presentations given were identical to the London event two days earlier.
3. The following additional questions were asked by the audience and answered by the Chairman and ISG Members:
3.1 The impact of national badger perturbation as a result of dry summers and food shortages which has nothing to do with culling; badger TB incidence during and after the Foot-and-Mouth epidemic; clarification of the variation in the effects of proactive culling by number of culls and distance from trial area boundary; options for a longer term approach to badger culling that exceeded five years; targeting less active and smaller setts to cull sick, TB-infected, badgers; pressures facing farmers at the time of a TB breakdown; TB compensation; gassing versus cage trapping as a method of culling badgers; cattle control methods; use of PCR.
4. Christianne Glossop, Chief Veterinary Officer for Wales closed the Meeting by thanking the ISG for agreeing to present their findings in Cardiff, and thanked them also for presenting a very detailed and thought-provoking final report.
5. The Meeting was attended by 119 delegates. The following organisations were represented by one or more individuals:
Allen and Partners
Animal Health
Animal Health and Welfare Strategy Steering Committee
Badger Trust (Wales)
Badger Watch and Rescue, Dfyed
BBC
BCVA
Brightwells Ltd
British Friesian Breeders Club
British Wildlife Management
Cardiff University
Central Science Laboratory
Clwyd Badger Group
Country Land and Business Association
Dairy Development Centre
DARD Northern Ireland
Deer Initiative Wales
Defra
Derbyshire Badger Group
Farm Animal and Welfare Council
Farm Assured Welsh Livestock
Farm Crisis Network
Farmers Union of Wales
Glamorgan Badger Group
Gwent Badger Group
HCC
Home Farm
Husbandry Working Group
Institute for Animal Health
Leicestershire Badger Group
Llanelli Naturalists
Maes Glas Veterinary Group
Milk Development Council
Monmouthshire County Council
National Farmers Union
NFU Cymru
NL & GH Land Dairy and Beef Farmers
Organic Centre Wales
POWA
Radnorshire Badger Group
Royal Society for Prevention of Cruelty to Animals
Secret World Wildlife Rescue
Shorthorn Society
Somerset Trust Badger Group
Specialist Cheesemakers Association
TB Advisory Group
The Central Association of Agricultural Valuers
Ulster Farmers Union
Usk Veterinary Centre Ltd
Veterinary Laboratories Agency
Watts and Morgan LLP
Welsh Assembly
Welsh Assembly Government
West Devon TB Action Group
Individuals: 19
Page last modified:
January 28, 2008