Back to warmwell.com website


December 14 2004

inter-breed variation in susceptibility to the TB agent provides a golden opportunity for some productive research.

Mark Purdey has just had to watch DEFRA compulsorily slaughter 80% of his pedigree downcalving Jersey heifers. They were to have served as the nucleus of his new herd. They had reacted to the TB skin test. Their pedigrees were irreplaceable, most of the animals out of 6.5% butterfat dams. Their conformations superb. He writes:

All of the TB reactors on my farm were confined to the Jerseys, whereas the same age group of Shorthorns that were co-reared alongside them ( and subjected to identical management conditions ) were all TB free.

I tried to drum up some interest with DEFRA in setting up a comparative study of the levels of micronutrients ( relevant to the immune response system ) in the blood / tissues of all cows that were TB reactors and all cows that were TB non reactors on my farm.

Of epidemiological interest, was the fact that all of the TB reactors on my farm were confined to the Jerseys, whereas the same age group of Shorthorns that were co-reared alongside them ( and subjected to identical management conditions ) were all TB free. So clearly, this inter-breed variation in susceptibility to the TB agent provides a golden opportunity for some productive research.

Whilst I have no complaints about the local DEFRA vets from Taunton - who acted brilliantly throughout this highly unpleasant ordeal - I really do question the whole approach of the upper echelons of DEFRA to the way that we are viewing and handling 'infectious diseases'.

In respect of TB, nothing has changed since the early 1970s when I first started farming. We know no more about the cause of TB today than we did then.

TB is an infectious agent, but the agent is endemic throughout the environment at large. It is airborne. So surely, the pertinent question is " What makes one individual more susceptible to TB than another?" This is a priority question that needs to be answered.

If we could answer that question (which some basic research /experiments should yield quick answers ) then we would be in a much better position to sort out the whole problem of TB - a problem that is proving to be a great loss of animal life, a loss to the farmer's breeding stock and cash flow, as well as to the tax payer.

Why on earth haven't we looked for the defective component in the AIDS sufferer's immune system that is making them so highly susceptible to TB ? The well known issue of AIDS sufferers succumbing to TB as a secondary complication provides a good starting block. Why on earth haven't we looked for the defective component in the AIDS sufferer's immune system that is making them so highly susceptible to TB ?

This is so simple, and, at a guess, probably relates to the inadequate T cell immunity. And what about the malnourished slum dwellers of the Industrial Revolution, or the starving crofters who were booted onto a boat bound for America, and who were rife with TB - why do we not consider those factors ?

...selenium can actually be knocked out of action ( locked up ) in circumstances where there is exposure to certain insecticides and heavy metals - despite it being freely available in the soil and feed on that farm.

In fact, some cursory book research that I have done since, has already shown that Jerseys are genetically predisposed to low selenium levels as a breed - and selenium co factors play a major role in activating the specific types of immune defence enzymes involved in combating the TB agent in the lung.

Whilst selenium may be naturally low in the local soils of some farms, selenium can actually be knocked out of action ( locked up ) in circumstances where there is exposure to certain insecticides and heavy metals - despite it being freely available in the soil and feed on that farm.

So many facets that influence selenium availability and other possible hitherto unidentified prerequisites (damp / dark conditions etc) and their possible relationship to TB susceptibility need to be explored.

Why isn't this crucial work being done, for a tiny millionth of the cost that our taxpayers are having to fork out for compensating the current TB fiasco?... I was told that I could conduct the tests, but I would have to pay for them at my own expense.

Despite blood having been collected from my whole herd for the brucellosis testing ( that was simultaneously conducted during the TB testing ), I tried to track down these samples at CVL to get them tested for micronutrients as well, but was told that it would prove too difficult to identify them and pull them off the conveyor belt - well, they would have to be identifiable for them to test for the brucellosis, surely?

Furthermore, if they had been retrievable, then I was told that I could conduct the tests, but I would have to pay for them at my own expense. Having bankrupted myself over my TSE cluster testing, I hardly felt motivated or able to take on the crucial research into another major public health issue.

Isn't it about time our authorities adopted a different approach to viewing disease?

Sure, these viruses, mycobacteria, etc, are out there - they always have been; but you DO NOT deal with this problem by simply slaughtering animals willy nilly and ignoring the critical underlying issues of compromised immunity that represent the real cause of animals succumbing to these diseases. The current approach is a more regressive approach than was operating during the dark ages.

The vets on the ground are good, intelligent people, but they have their hands tied behind their backs.

The real problems once again stem from the same misguided advisors....

Mark Purdey