9 Jun 2008

The real cause of cattle TB

Badger culling is still on the agenda - a decision looks likely in coming weeks - maybe even this week. I've discussed this issue at some length with farmers who are for and against a cull and with a vet who is convinced it is the only way forward. However from all the evidence I have seen there is still not evidence that badgers cause TB in cattle - indeed if anything there is more evidence of the other way around. The letter below is in today's Citizen today from Martin Hancox who I have also spoken to today and previously. He makes a useful contribution to the debate. Certainly urgent attention must be given to this issue as farmers are being left in impossible situations - indeed it is an outrage this has gone on so long.


Copyright photo: Badger by Tony Evans Nature Picture Library reproduced with permission from Stop War on Badgers

According to a leaked source, Environment and Rural Affairs Secretary Hillary Benn told colleagues that he "was not persuaded by the science behind badger culling", hence his delay in responding to the EFRA Committee report and any decision on a cull. Quite right too. While farmers are very certain that a cull is necessary, many herds have been under TB restriction for years - and these cases are proof that it is not Old Brock after all.

Up to 30% of cows go temporarily non-reactor after giving birth, and some of these go on to become totally "angergis" or non-reactor, while still actively spreading within the heard. So, in many big dairy herds, the repeat tests skim off new cases but fail to remove the culprit.

There are two very simple things which could be tried:

1. Since the blood IFN test is being used on such herds, it would be very easy to use a sub-sample with the Brock stat pak test which targets such late TB anti-body levels.

2. Cows can be shedding 38 million bacilli in 30lbs of faeces per day, and PCR (DNA) tests on faecal swabs give results within hours, costing £6-10.

M. HANCOX, Nouncells Cross, Stroud

For previous blogs and campaigns on this topic use the search facility and see
The Badger Trust.

1 comment:

Philip Booth said...

More from Martin in todays Citizen:

THE great badgers and bovine TB debate has rumbled on for 37 years and has now come to a head with the current cattle TB crisis. Farmers and vets are certain badgers are the main reservoir of TB so insist a cull is essential. But everyone has forgotten how TB works in cows and why badgers got the blame in the first place.

TB spreads within and between herds if unchecked. So the whole point of annual testing is that it removes cases before they can pass TB on, and herds under restriction are not exporting TB carriers. So TB shrank to tiny south west hotspot pockets by the early 1970s, without any badger culls. Alas, the second impact of intensive testing is that cases are found so early that they are unconfirmed being without lesions or M.bovis on culture … but at least 80 per cent of such cases do have TB. In addition tests completely miss early and late TB cases so there is a huge 'undisclosed' reservoir of cattle TB. And that is why Old Brock got the blame by default.

With intensive annual testing in hotspots since the war, it seemed as if cattle were not the main infectious source of TB. Hence the lack of testing due to Foot and Mouth in 2001 was a one-off disastrous 'experiment'. TB exploded out of control with 30,000 reactors in 2005: twice the level as at the start of the area eradication scheme in 1961. Local movement of cattle expanded the former hotspots into one big hotspot in Devon/Cornwall. And worst of all, many big dairy herds now have non-reactor or anergic active spreader cases so have been under restriction since FMD or longer. Zero tolerance on overdue herd tests and more testing has begun to reduce the crisis without any need for badger culls.

Professor Bourne and the ISG's report last year claimed that proactive culls reduced cattle TB by 23 per cent, but due to perturbed badgers increased it by 20 per cent (reactive) to 25 per cent outside proactive areas. But this is complete and utter nonsense, since out of 11,000 badgers culled only 1515 had TB; in nearly half the 51 proactive culls there were 15 or fewer with TB out of 100sq km, and in total only 166 with advanced lesions which might have been a risk to cows (though it is still unclear how badgers are supposed to give cows a respiratory lung infection). The rises in TB happened before the reactive cull inside and outside no cull areas and was part of the national upsurge.

Innocent bystander, victim not villain.