Wednesday, January 11, 2017

Cattle Health Schemes - an unwanted, unworkable addition.

Various bodies operate cattle health schemes in the UK, and are very enthusiastic about adding a new disease to their piggy bank  disease risk portfolio.
We mentioned this in less than glowing terms in our September posting - [link] with a withering swipe at Chief Vet, Nigel Gibbens, for describing those of us who try and farm cattle in a responsible way in his 'High Risk Area' for TB as 'unlucky'.

We are not 'unlucky' at all. As we said in the that posting, we and our half a million dead cattle, are victims of governmental neglect of the wildlife reservoir of zoonotic Tuberculosis on a monumental scale over many decades.

 But despite the fact that zTB is primarily a spill over disease into cattle, from a maintenance reservoir in an untouchable wildlife source which has acquired cult status, the umbrella organisation CHeCS ( Cattle Health Scheme Certification Scheme) have launched their New Year with a flourish.

They and Defra Ministers describe their new risk assessment for zTB as 'rewarding farmers for good biosecurity'. So how has this risk assessment been prepared?

Working from a list of some very dubious 'factoids', the ESVPS (European School of Veterinary Postgraduate Studies) have developed cobbled together a risk assessment hymn sheet [link] for vets to refer to. At the time of writing, numerous meetings have been held to promote this, but we are unsure whether the pamphlet in the link is the final draft, or a primary. The gist of it however is clear enough. Badgers with TB pose a huge problem for cattle farmers, but 'responsible cattle farmers' will keep them away from cattle.

And once again, Defra have thrown this thorny problem to another outside agency, in this instance a veterinary one, and cobbled together the risk of TB with other uniquely cattle diseases.
And that you cannot do.

To compare TB carried by wildlife and their detritus, with such uniquely cattle problems such as BVD (Bovine Viral Diarrhoea) IBR, (Infectious Bovine Rhinitis) Leptospirosis or Johnes disease etc. is both crass and unhelpful.

 The notes from which the Risk Assessment appears to have been drawn up, are mainly computer generated assumptions and factoids, bearing little relation to actual 'risks' which may practically be avoided on any working cattle farm.

Below we list them, with our interpretations:
1. In high risk areas, farms with herds of >150 cattle are 50% more likely to suffer a bTB outbreak than those with 50 or fewer

2.In herds with endemic bTB, herd sizes >300 are likely to circulate disease at a level which may be missed at individual TT test.
That computation is mathematical, not a given. Test 500 cattle in one herd and get one reactor, but test 500 cattle split between ten herds and nine herds will be clear. Simples.

3. Dairy herds tend to undertake higher risk practices including feeding. They also tend to be larger.
' High risk practices feeding Dairy herds’. Are they referring to maize or the way cattle are fed in the shed? Sheds were perfectly O.K until badger numbers got out of hand and used cattle feeding areas as their very own Badger MacDonalds on a regular basis. Grass silage too is mentioned, incurring (shock, horror) a 50% 'risk'. Just what else cattle are to fed during winter months is not explained as 'rough grazing' is also damned, incurring penalties.
4. The risk level can be assessed as highest when groups of cattle are purchased regularly and can be reduced by reducing the frequency of purchase and the size of the groups purchased.
Farmers are trying to run commercial businesses. This document appears to say that farmers should not purchase cattle, or only very occasionally and then  in small numbers. Several of our contributors run 'closed' herds using artificial insemination, have no bought in cattle at all and secure boundaries against any cattle contact. It makes no difference at all to an infected badger. He can infect any cow, any time, whatever its original home.
5. A small scale survey is ongoing to investigate whether reducing the water level in water troughs makes them less attractive to badgers who may not be able to reach in for the water level. This remains an experimental hypothesis at this time.
Experimental hypothesis??? How are smaller calves meant to drink? Via a U shaped straw?
6. Maize is grown on farm or by close neighbours and /or maize silage is fed to cattle leads to a 20% increase in TB risk per 10ha of maize grown.
So the growing of a wonderful home grown source of starch and sugar for cattle feed, is a 'risk', merely because it is also 'valued' as a magnet, by an overprotected pest? Add that to the grass silage and rough grazing previously tabled and cattle are left with precisely what to eat? Thistles?
7. Building access by badgers is recognised as a greater risk than occasional pasture contact.
It doesn't matter how or where cattle come into contact with badgers, if those badgers are infected and infectious at the time of contact and leave behind them infected evidence of their visits. That can be in farm buildings or grazed grass. A reactor is still a reactor. And she's shot.
The infectious culprit continues on its merry way.
8. Badger tracks are recognised as a lower risk than latrine and shared feeding areas at pasture
Badger tracks are still subject to the contents of leaking bladders and scent marking for territorial boundaries. They will use the same tracks too and these lead to 'badger feeding areas' (grassland) containing dung pats etc.. And badgers constantly create new latrines, now that their numbers are so great.
It is not explained how farmers can shrink wrap cattle grazing areas.
9. This [ nutritional deficiencies] may increase susceptibility to TB
That assertion was not born out by the salami sliced post mortems of reactor cattle in the the £2.8m Pathogenesis project - [link]
10. This (above?) should include Johnes disease vaccination if utilised. Using a Johnes vaccine may increase the chances of not detecting infected animals. Work is underway to investigate if the gamma interferon test may be of use in this situation.
Vaccines for Johnes [m.avium paratuberculosis] is not available in UK, as far as we are aware.
11. Evidence to support previous recrudescence or repeated incursions of bTB will need to be looked at in conjunction with the genotype results from infection in SICCT positive cattle.
How about looking at whether badgers have continued and are continuing to visit cattle areas rather than assuming recrudescence via cattle? And if you slaughter out the primary Genotype (should one be found) what happens to number two? Or three? Or four? Cognitive dissonance? No cattle = no TB.
12. There is an odds ratio of 3.1 times greater risk of lifetime risk of becoming a reactor if an individual has at any time tested as an inconclusive reactor.
Not in our, or ex DVMs practical experience over decades. Mathematical models again using assumed data?
13. Even relatively short extensions in the testing interval are associated with an increased risk of disclosing disease in the high risk area.
This will no longer apply as any farmer going over the stated window for his herd's TB testing, automatically has BPS docked and his herd put under immediate restriction. Penalties for any reactors found are also in the pipeline. All certain to focus the mind.
14. If the period of time during the test is prolonged, this can exacerbate the impact of any spread within the herd.
Some extraordinary grammar in that one. A longer time for a vet to test cattle, or a longer period between tests? We'll assume the latter. But if testing periods are extended and exposure has longer to generate lesions (as in four year testing areas) then more lesioned reactors than NVLs would be expected.
15. If this is the case, then local spread from either wildlife or locally purchased stock is suggested. If this is not the case, then purchase from outside the area is suggested.
Spoligotypes will nail that question, without making any more wild assumptions.
16. Byrne et al identified in 2012 that the average maximum distance a badger would roam was 2km. However, under exceptional circumstances hungry animals were found to roam up to 7.5km from their sett, possibly over a couple of days. The risk level can be assessed as highest when groups of cattle are purchased regularly and can be reduced by reducing the frequency of purchase and the size of the groups purchased.
One minute talking about badger ranges and then goes back into stopping farmers purchasing cattle??

And if Woodchester Park's peanut fed pets were used as the guinea pigs for Byrne et al, then forget distance. In the real world, territorial distances traveled are reported to be much, much more. In fact we have been told that one Woodchester badger, collared to track her movements, trundled 21 miles to Bristol Docks. And returned after viewing the estuary. But we don't expect Byrne or et al was told that.

We are told this is an industry led initiative. Really? The names of the AHDB, APHA, DEFRA and the NFU appear as endorsements. Did they really understand what they were suggesting?

We would reiterate, as would our supporting vets, that in no way can the disease zoonotic Tuberculosis carried by over protected wildlife,  be compared in terms of 'risk' with that of genuine cattle diseases, some of which we mentioned above and over which farmers do have an element of control..

So from that list of 'risks', is Damien Hirst's cow offering the only 'safe' place for our cattle to exist?

In a hermetically sealed tank full of formaldehyde, to protect them not only from infected wildlife, but a gravy train of hangers on intent on trousering cash from government negligence?

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