Wednesday, May 14, 2008

Carnage

... or death by one thousand cuts. Today, over 80 of Tony Yewdall's newly calved pedigree guernsey cattle were slaughtered. We covered the story of this farm's Tb problems here in 2004, but last November two further reactors were identified by the skin test. Defra moved in to blood test the cattle. Why, when the herd had ongoing Tb problems, a history of Johnnes disease and hundreds of badgers, is for them to comment on. Not the brightest idea, one would have thought. The result was a far cry from a couple of reactors identified by the primary skin test. A devastating 89 cattle failed the blood test.

This led to the appeal in the High Court last month, on behalf of several farmers including Mr. Yewdall, who requested a judicial review into the use of this test. Meanwhile the cattle have been in isolation and on regular Defra watch pending the outcome which we covered in this posting.

The farcical failure of this appeal for Common law over disputed statute, is one of life's mysteries. And today, Tony Yewdall's cattlepaid the price.

South west newspaper, Western Morning News carried the story:
Today, the Yewdalls are debating whether to remain in the business amid the double blow of losing a third of their valuable dairy herd and the fear many of them may be perfectly healthy. Mr Yewdall, who successfully resisted having his herd culled during the foot and mouth crisis, said today's blow could be the last straw. "It's a difficult decision, but getting out of farming is certainly an option," he said. "We will have to see what happens with TB in the future. The really hard thing is that we question how many of these animals actually have TB, and that won't be answered until tests are carried out once they are dead.It's a dreadful situation for us."

His son, Jonnie Yewdall, estimated the episode would cost the family about £100,000 -particularly as Defra is paying the [tabular] compensation value for each cow based on November's prices, which were lower than today's.

He said the family had offered to pay for a retest privately, but Defra had refused to grant the necessary authority to do so. "Why would they refuse if they are confident in their results?" he asked.
"Nobody's doing anything to stop badgers spreading TB to cattle. If we carry on in farming, it's as if we're sentencing our cows to a premature death. It's like banging your head against a wall."

A Defra spokeswoman defended the differences between the skin test and the blood test, known as the gamma interferon test. She said:
"Research shows the two tests identify different populations of infected cattle. The gamma interferon test can identify infected animals at an earlier stage in the disease as well as infected cattle that simply fail to react to the skin test. In herds with confirmed infection, the use of both tests in parallel offers the best prospect of detecting all infected at the earliest opportunity."

Well she would say that wouldn't she? Sheesh - that 'earliest opportunity' is just 12 days. The difference between the latency of the skin test (picking up exposure to m.bovis) at 30 - 50 days post exposure, and gamma at 28 days average. Of course it also, as that shambles of a Pilot study found, picks up a whole shed load of other contaminants and relabels them 'm.bovis'.

And joining in the clamour to use this bluntest of blunt instruments, is none other than our old friend, Trevor. Yup, Mr. Lawson loves it, arguing that gamma interferon
"... provides a very rapid and very reliable test for bovine
TB.It only requires one visit from the vet and the results can be ready in 48 hours. Furthermore, the cut-off point for the test can be adjusted, so that a 'false positive' diagnosis can be virtually eliminated. Although this does mean that some infected animals could be missed, it is still far better than the skin test, which misses around one third of infected cattle. If a positive diagnosis were in doubt, it could then be verified by a more specific gamma interferon test to minimise the risk of slaughtering a healthy animal."

Although we are delighted that our Trevor has concerns about slaughtering healthy cattle, his spin interpretation of the test sounds to good to be true. And of course it is. We are not sure which planet - or should that be sett? - Trevor Lawson inhabits but not the same one as the rest of us. Flexibility? Not on this watch. And not at all in Tony Yewdall's case. Cut-off point adjusted? Nope. It's set at 0.1 and not adjusted for farm circumstance, contaminant circumstance or any other goddamn circumstance. False positives virtually eliminated? Well, we'll see. Skin test reactors show about half +/- 50 percent to have confirmed disease, compared with 18.6 percent 'reactors' to gamma. As Mr. Yewdall said, only postmortems will tell the whole story. These cattle failed the blood test in November. Six months ago. They were slaughtered today. And if Defra are right, every last one should have developed full blown disease, defined by Visible Lesions or cultured samples. And of course that will be the end of Mr. Yewdall's Tb problems won't it? The blood test having hoovered up all the cattle the skin test failed to find? Not necessarily. In fact highly unlikely. And that 'thirty percent of cattle' that the skin allegedly misses ? Selective spin. For goodness sake man. Get a grip. Or better still read this

But we are not alone in wishing that a blood test would sort the problem out - the problem of 50 per cent of skin test reactors proving negative to tuberculosis on postmortem would be a good start. (94 per cent of ours) But it won't. In fact the rigid cut off may actually target cattle which have acquired a degree of resistance to TB infection, so it could actually be counter-productive. There will still be infected animals on Tony Yewdall's farm - but they won't be the cattle...

An MRCVS veterinary surgeon described his experience of the gamma test thus;
All my clients who were ‘conned’ into having the blood test - one twice -lost many times (10/20? times) more cattle than would have been expected and therefore necessary. All of them still have a TB problem in their herds. None would “go down that route again”.
One client with a long standing, ongoing problem, had had tuberculin tests virtually every 60 days for the previous 4 years. A tuberculin test with 2 reactors, was followed 21 days later with a blood test with 23 more ‘reactors’. 41 days later, I found 27 more reactors of which 13 had lesions. There was a lot of badger activity.

Until the infected badgers are culled there is no place for the blood test. When they have been culled there will be no need for the blood test!

We will add more links from other publications on this story, as we get them.

UPDATE
The postmortem results on Mr. Yewdall's cattle are now to hand. After 6 months in isolation, just 2 cattle had Visible Lesions and a further 3 were found to have the very beginnings of small closed granulomas. Over 80 cattle were slaughtered in this carnage - as 'reactors' to the secondary, ancillary gamma interferon blood test. They had survived under an injunction for the best part of eight months in which the opportunity was there to produce full blown disease and prove Defra's point.

What a splendid result for our beloved Defra.
What a total waste of £200,000 for the UK taxpayer.
What a devastating and irreplaceable waste for the Yewdall family.

And a similar result has come from the Burrow Farm Organic Partnership, whose case for a Judicial Review of the secondary, ancillary blood test after some more spectacular results failed last month.

88 cattle went for slaughter this week. Just two had visible lesions consistent with confirmed tuberculosis. These cattle, as with the Yewdall's herd, had been in isolation for several months, pending the court decision. Defra's defence of this brutal of blunt instruments as 'flagging up early detection' of Tb, is looking decidedly thin.
See also comment below from a farmer who kept a gamma postive cow for twelve months, arguing for a skin retest. The animal was negative on both VL and culture but at postmortem was found to have harmless epidermal granulomas known as 'skin tb'.

We did entitle this posting 'carnage'....

More on this story from Christopher Booker's Notebook
in the Sunday Telegraph.

4 comments:

Jim said...

Yet more proof, if it were needed, that Defra's stock response that the gamma test picks up infected animals earlier is a paltry excuse for their inability to admit they are wrong to have staked so much on the gamma test. The test picks up far too many other things, and condemns animals to slaughter needlessly. We had a gamma positive cow which we managed to hang onto for 12 months before slaughter. She was no-visible-lesions and culture negative, but what they did find at post-mortem was evidence of skin TB. Q.E.D.

As for Mr Lawson, I seem to recall that he uttered the immortal line that "cattle are culled anyway", so thatt's all right then....Well, our cow had probably another 8 years or so ahead of her.

Anonymous said...

Hello Jim,

What is "skin TB" please?

Jim said...

Anon 4.52:

Skin TB is a different mycobacterium which, as I understand it, is considered perfectly harmless. (The symptoms in our cow were small lumps just under the skin in one place.) The Defra vets who did the post-mortem were not in the least concerned. However, being a mycobacterium, it can produce a positive result to the gamma test, as that test is poor on specificity. Hence so much needless slaughter.

Matthew said...

Anon. 4.25.

From a veterinary text book: Skin Tb, is an description for nodules seen on the legs or necks of cattle, often in the form of a chain of small lumps. These are non infectious and harmless to the animal but may contain an acid-fast bacteria which if it is contact with a skin test jab, could interfere with the result.

In practise, vets are careful to mark any such lumps on the skin test charts and avoid them.
As Jim said, no such luxury is afforded by the gamma blood test.