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Tuesday, June 01, 2010

Latest figures on bovine TB - is a cull actually needed?

I have received an update of the figures I previously published on this blog concerning the number of incidents of TB in cattle in WAales which I reproduce below:

I have been looking into the stats for bTB in Wales and have noticed a substantial fall in the bTB figures starting around April2009. For example look at herds under TB restriction.

My sources are all DEFRA statistics and I have attached copies.

April 30th 2009 (Wales) Herds under TB restriction 1,983
February 28th 2010 (Wales) Herds under TB restriction 1,117.These figures are actual and ‘on the day.’ They do include herds late with their tests.

Dyfed works out at about 36% reduction in herds under restriction in the last 10 months (April 30 2009-Feb28 2010) but if you subtract the ‘overdue test factor' you get about a 40% reduction.

Wales with the overdue tests factored out you get a reduction of 58% over the same period

I have attached Defra's own assessment for GB of CNI's which is the rate of Confirmed New Incidents (bTB) in the UK per 1000 tests on clean herds and though they are provisional, they show a 14% reduction Feb 2009 to Feb 2010. Again this is ‘substantial.’ If you take the actual UK figure for 2008 however, (CNI’s, % of tests on unrestricted herds resulting in a new herd breakdown) which stood at 5% then and the figure for this February 2010, which is provisionally given as 3.8% the downward trend is again confirmed.

The yearly figures given below and in the ‘attached documents,’ are ‘actual’, but somehow are marked as ‘provisional’. Can they still be working on figures for 2008/2009? After all it is nearly June 2010.

CNI's in Dyfed 2008 were 301
CNI's in Dyfed 2009 were 234

This represents a ‘substantial’ actual drop of over 22%, better than in the rest of Wales. They are finding a lot less bTB out there, how is this possible without any badgers having been removed? We are told that it is badgers who are infecting cattle yet incidence of the disease is in ‘substantial’ decline.

(UK figures released by the Agricultural Department 19 May 2010 show an (provisional) overall decrease of 14% Feb 2009 to Feb 2010.) 1

The disease is in decline because of the increase in cattle testing over the last two years along with the removal of infected cattle the real vectors of this disease. If all the many recommendations for improvements regarding cattle control measures, given by the ISG in their Final Report, were implemented, the disease would rapidly disappear as it did in the 1960's without badger culling. (Note that Macrae the Chief Veterinary Officer at the time, in his final report does not mention badgers once).

However if we fail to get these figures out now as the cull starts, the decline in cattle TB will be acknowledged and attributed to the badger cull. It will be the excuse for extending the programme over the whole of the country!

WAG has been very quiet about the decline of bTB in Wales as it demonstrates convincingly that even their limited cattle measures are having an effect. There was never a reason to consider culling badgers. WAG's whole premise for culling badgers was that the disease was 'un-sustainable and out of control.' The estimated compensation bill given in 2008 by Elin Jones for 2014 was £80 million. That figure now looks absolutely ludicrous!! The only factor out of control was the industry itself, already we note that overdue TB cattle tests so proudly claimed by WAG to be down to near zero last year have risen dramatically to 702 this year.

Links to the relevant sites are here, here, here and here.
There's probably more TB in the human population of Wales than in Cattle or Badgers.

What's the parish council doing about that?
Ive been following the Defra numbers for a while and the trend is clearly down Ive today written to all AMs with a summary and links in case they are not smart enough to read this blog (at least 3 times per day) Thanks Peter we will beat ignorence yet
It is totally inappropriate and unscientific to use the reduction in herds under restrictions as a measure of a fall in bTB incidences, because the majority of this reduction has resulted from the zero tolerance approach to overdue tests brought in by WAG in the past eighteen months. Overdue tests automatically lead to movement restrictions, irrespective of whether or not there is bTB on a holding, so cutting down the number of overdue tests has resulted in a fall in the number of holdings under movement restrictions. The fall in the number of overdue tests was around 42% between December 08 and December 09, which is similar to the fall in herds under movement restrictions. This is a classic example of using a completely invalid statistic to justify an argument.

As far as the 5.6% reduction in Welsh reactor cattle from 2008 to 2009 is concerned (and this is a genuine rather than spurious measurement of changes in bTB detection), we are all hopeful this reflects a real fall in bTB incidences, but it is quite likely that this a statistical blip, possibly caused by a recent switch from using tuberculin manufactured in Weybridge to imported tuberculin. The last time we started using imported tuberculin we saw a fall in bTB incidences, and DEFRA and Groups like the Badger Trust (possibly called the National Federation of Badger Groups in those days) all said this showed new cattle controls were working, but in the long term all that happened was we saw a massive increase in bTB incidences later on. For more details see www.farmersguardian.com/defra-admits-tb-test-flaws/3272.article

The way in which statistics which are either inappropriate or just plain lies are being used by the anti cull lobby is quite disgraceful. The only approach which has been scientifically shown to reduce incidences of bTB by as much as a half compared with reference areas is badger culling, and that is a figure you cannot deny because it is given in the final report of the ISG!
I am more than willing to accept your interpretation of the statistics on the fall in bTB incidences though it seems to me that you want to have your cake and eat it on the 5.6% fall in Welsh reactor cattle. However, your interpretation of the ISG report and your ignoring of teh subsequent follow-up report is as dishonest as anything you accuse the anti-cull groups of. In fact the ISG report was quite clear that culling can spread bTB whilst the subsequent report showed that in the long term it made little or no difference to incidents of bTB.
The ISG report did not show that culling spread TB per se. What they showed was that localised culling spread TB, while proactive culling reduced TB in culling areas of 100km^2 by 23% and increased it by 25% in the surrounding areas. The ISG report also showed that proactive culling reduced TB by 50% in the centre of culling areas. The first follow up report showed a reduction of 54% in the proactive culling areas and a reduction of 23% in the surrounding areas following the cull. The second follow up report suggested that this positive effect had died away to zero after a number of years. The last follow up 'report' (it can hardly be described as a report as it is very short) shows that in the 6 months to January 2010 bTB was 44% lower in the cull areas than in the control areas. For the entire post cull period TB was 37% lower in cull areas, and 4% lower in surrounding areas. Those are the figures, without any spin in either direction.
The author of the letter cited very clearly addressed the issue of overdue test herds being included in the herds under restriction.

And the ISG report did very explicitly find that even proactive culling 'spread' TB - in their own words:

"Probably as a result the proportion of badgers infected with M. bovis rose markedly in response to repeated culling, and infections also became less spatially localised. Hence, although proactive culling reduced badger activity by approximately 70%, reductions in the density of infected badgers were much less marked, and infections became more widely dispersed (Chapter 4)."
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