Tuesday, August 21, 2007


The Veterinary Record last week contained two letters of interest to this site. And as we like to end on a cheerful note, we quote a lightweight piece of political opportunism first.

This came from the president of the BVA (British Veterinary Association), David Catlow, who explained that his organisation had deliberately taken the time to digest the contents of the ISG RBCT Badger Dispersal Trial 'Bible'.

The implication is therefore that veterinary colleagues who have already commented, had not digested the report? But we digress.

Mr. Catlow wants to know where the report "fits with our existing bovine tuberculosis (TB) control strategy". Well that is quite easy. We don't have one do we? Haven't had for some time. He continues: "What is quite clear is that the report gives no clear direction on how best to progress the control of bovine TB".

Actually, it does. The ISG confirmed that badgers do give cattle tuberculosis, and told us how NOT to deal with it. Mr. Catlow points out that the ISG report states "that bovine TB infection from badgers to cattle in endemic areas could account for up to 50 per cent of cases". This curious figure may have its roots in the methodology of the ISG mathematical modelling as described in 7.19, where they describe the choice of a "simple model, highly idealized but intended to capture key features of the epidemic". Fast forward now to 7.24 of the ISG 'Bible', where the explanation of such modelling informs the reader thus:
"The effect of changes cannot be assessed directly from available data but simple mathemetical models, combined with the large amount of data now assembled do allow some very tentative predictions. The infection rate concerns all sources of infection for cattle, local infection across farm boundaries, infection from animals bought, in particular but not only, from high incidence areas, and infection from wildlife especially badgers."

And then the crucial bit. Far from using the cumbersome TB99 and local AHO knowledge on breakdown farms available, including mapping in the case of shared boundaries, and BCMS / CTS records for bought in cattle, the modellers of the ISG describe their 3 choices for comparison of risk thus:
"All these are important, but their relative importance and that of cattle-badger transmission, cannot be estimated directly. In the following calculations we assume all three souces to be roughly equally important"

So, "tentative predictions" made on "rough assumptions" of transmission opportunities at the rate of "2 cattle : 1 badger" were pumped into the modelling computer's abacus? Is that right? Of course the relative causes of breakdown herds could and should have been more refined than that. It was too much goddamn trouble to ask. So out extrudes a deliberately vague reference, not supported by the CVO's previous annual reports which attributed up to 90 per cent of cases to badgers.

On that side of this unequal 'rough assumption", the BVA have this to say:
"It remains the BVA's view that addressing this transmission from wildlife is an essential part of a bovine TB control policy in endemic areas. It is evident from the spiralling incidence that cattle controls alone are inadequate to control the disease. Obviously, the vaccination of cattle/badgers is desirable, but since no effective vaccine is yet available, more immediate steps need to be progressed.
We have suggested and discussed the feasibility of a study for designing an efficient and humane badger culling programme, within the constraints identified by the ISG report, with appropriate consideration given to addressing the 'edge effect', compliance, social and political acceptance and cost. Other suggestions include developing PCR technology in order to identify and selectively cull only infected badger setts".

OK as far as it goes. Nowhere near robust enough, but then these were the chaps who were defending to the hilt, practising veterinarian's 'rights' to Tb testing. They publicly and vehemently opposed lay testers, on the grounds of losing cattle vets from their practises. And once again in this letter, their constant but consistant political opportunism appears. Having given credence to the unique 'edge effect' that Bourne experienced, the BVA then parrot the ISG's demands of extra cattle controls, 'bourne' of the modelling excercise described above;

Reducing the spread of the disease remains an essential part of any strategy, and the BVA discussed with TBAG what further refinements in cattle controls might be beneficial and therefore warrant further examination. These include:
 Exploring what potential exists for extending the role of the gamma interferon ( -IFN) test;
 Altering the frequency of bovine TB testing - whether the frequency of tests could be reduced in some areas to allow deployment of increased resource in others;
 Developing the concept of pre- and postmovement testing;
 Enhancing speed of removal of reactors from farms;
 Developing the concept of risk-based cattle movements. Herds of similar risk might trade relatively unrestricted but higher-risk movements might be subject to further assurances to reduce the cattle spread of disease into new herds and regions;
 Developing the role of the LVI in order to facilitate the tracing process of infected animals.

Straight from the ISG Bible. The only thing they've missed out is whole herd and cohort slaughter. How could they miss that? They said they had 'deliberately taken time to digest the report' did they not? But it's there in all its gore glory, both in 'low risk areas' and 'high incidence'
10.67 .. slaughter of the whole herd or cohorts of animals in affected herds. It would be advisable to be rigourous in these situations, and whole herd slaughter should be a more readily excercised option for heavily infected herds". (This for low risk areas)

10.74 Previous testing history will reveal a hard core, possibly 5 per cent or more of these multiple reactor breakdown herds in high risk areas which have been difficult to clear of infection. These herds pose a substantial disease risk and should be considered for whole herd slaughter or slaughter of cohorts with a history of infection.

But ever consistant in sourcing veterinary opportunities, the BVA have ignored this little gem and cherry picked concentrated on the testing part. They have also ignored the restocking options. Do they really think that after whole herd slaughter, Defra are going to allow cattle back onto that farm to be reinfected from a 'non-bovine source' as they so quaintly describe it? Already farmers in that position are being advised, 'respectfully' of course, that a cattle restock option would not be wise, due to infection from such 'non bovine sources'. But as we have said, the BVA are happy to cherry pick the ISG Bible for veterinary opportunities, and propose more frequent testing. More frequent than what? every 60 days for years? Sheesh. Pre and post movement testing, zoning of areas and the inevitable extension of veterinary expertise to accomplish this. Piling up dead cattle higher and quicker then. With approximately 5 per cent of the herds in Wales and the West region (Defra figures to May) slaughtered out altogether. That's 180 herds who won't need a cattle vet then?

The BVA were involved in the last government strategy 'package'. They have learnt nothing. You do not play political trade offs with politicians.

By unquestioningly grabbing at these lightweight LVI opportunities, the BVA must have made government's day. They can go ahead with the tacit agreement of (some) veterinarians along the lines of the ISG 'Bible's' cattle carnage 'science' which has already told them that this alone will reduce bTb by 15 per cent per year. But if the president of the BVA thinks he can offer these sacrificial lambs (or in this case, calves) in exchange for a badger policy at the same time, history and bitter experience suggests he may have to think again. "We won't know which is working" will be the clarion call, "so one strategy at a time gentlemen,- but obviously with cattle measures first". Cynical? You bet we are.

The other letter which the Veterinary Record published, carried a more positive embrace of veterinary responsibility for diseases in wild animals, their transmission and the welfare of sufferers. It came from Mr. I.F. Keymer, a former government veterinary employee, whose interest extends beyonds the politically acceptible. He congratulates Defra on recognising the importance of diseases and zoonoses in wild animals and their transmission to domestic stock. Mr. Keymer's letter concludes:
"I hope that Defra with its new responsibilities, will now take more positive action to tackle the welfare problem of bovine Tb in badgers. The infection has now spread to several other species of wild mammal. Urgent action is therefore required to prevent further spread, especially to cattle".

Yes, it is. But with opportunism as exhibited by the BVA's letter above, it won't come anytime soon.

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