Tuberculosis Report

I have a confession to make I was hoping by now that I would have had a chance to study all of the two hundred and eighty nine pages of the Bourne report into bovine tuberculosis. So far I have managed to get half way through and the more I read the more confusing it becomes. For instance he points out that when tuberculin testing was first started in the mid nineteen thirties forty percent of the national herd were infected and there were 2,500 human deaths a year from the disease. By 1964 the infection rate in cattle had dropped to 0.06% which was a remarkable achievement considering our limited knowledge of the disease at that time. He goes on to say that the skin test has its limitations, which we all accept, but it can not be that bad as it detected all of those infected cattle in the first thirty years before cattle crushes and ear tags were in regular use.

Clear Conclusions

One of the striking things about the report is that they have no doubts that any form of badger culling will not have a beneficial impact on reducing the incidence of the disease in cattle. Indeed they point out that it might well make the situation worse as the disrupted badger population will move in and out of the controlled areas and disperse the disease further. There is no suggestion that any other view might have some merit. Cost is mentioned several times when badger control is discussed.

Proposed Control Measures

The control measures that are suggested involve more cattle testing. To re introduce annual testing in low risk areas, to retest breakdown herds after three to four weeks rather than sixty days as at present and to make more use of a blood test in breakdown herds to try and detect more infected cattle before they can spread the disease. They talk about isolating cattle when they first go into a herd until they have had a post movement test. There are proposals to classify herds as low risk if they have not had a reactor in the past four years and high risk for all of the others. No cattle would be able to move from a high risk to a low risk herd. They suggest that problem herds where there are more than two reactors might benefit from the slaughter of all of the cattle that have been reared with the reactor. In some herds where the re infection rate is high they propose that whole herd slaughter is the way to deal with the problem. There are few mentions of cost when cattle measures are discussed.

Different Categories

There is some benefit in these proposals although they would be expensive to implement. No distinction is made between animals destined for breeding, and staying on a farm for some time and those that will be fattened in buildings which are a little risk to anyone as they do not have very long for the disease to develop before they are slaughtered.

Badger Numbers

It would seem to me that something has changed in the first thirty years when tuberculosis was common in the cattle population and dropped off dramatically when the skin test was first introduced. Were there infected badgers about then or were they so scarce that they did not matter? I was brought up in a small village in Sussex and when I was young I can recall rarely or never seeing a badger (or a buzzard). Now they are common near the village where I used to live. I know badgers were not protected then, but I cannot think that many were killed maliciously; if they were I was not aware of it happening, they just were not about. It is difficult to know what has changed to make the badger population grow so much each year.  There must be some explanation, milder winters, growing maize, bigger cattle herds, more intensive farming perhaps. If we knew why there are so many badgers we might be able to discourage them and get their numbers back down again.

Different Approach

There must be a solution to this problem. Badgers have specific requirements for where they locate their sett. They prefer to dig into a slope where there is some tree cover so that they are hidden when they first emerge. They dislike heavy soils. In most areas there may not be many sites that suit them and it might be possible by some electronic device to discourage them from settling.

Breeding Control

Also they have a short breeding season as all of the offspring are born in February. There are drugs that we feed to feral cat colonies sometimes to stop them breeding. This can have a dramatic effect on the numbers of kittens produced to stabilise their population. It has been estimated that the average survival time for badgers in the wild is three years, less perhaps if they are diseased. It would seem to me that there are other humane ways of controlling badgers that does not involve killing them.

Conclusion

The Independent Scientific Group has been pondering their findings for ten years, sadly two of the original members died before the report was published. They are not optimistic that a vaccine for either cattle or badgers will be developed in the near future. Their two main conclusions are that after careful consideration of all the data and an economic assessment badger culling cannot meaningfully contribute to the control of cattle TB in Britain.

New Control Measures

They further conclude from all of the scientific evidence available that the rigorous application of heightened control measures directly targeting cattle will reverse the year-on-year increase in the incidence of cattle TB and halt the geographic spread of the disease. I hope that they are right, it should not take very long to find out.

Other Species

In the same week that the report was published a short extract appeared in a veterinary journal that stated that Mycobacterium bovis has been discovered in the carcases of the following animals found dead in south west Britain in recent years. Foxes, stoats, polecats, common shrew, yellow necked mice, field voles, grey squirrels, roe deer, red deer, fallow deer and muntjac deer. This is quite a list. Tuberculosis is recognised in cats and has occasionally been diagnosed in dogs that frequent rural areas. It has also been reported that two Alpacas that died locally of an acute pneumonia have been shown to have numerous organisms present in their lungs thought to be Myocbacterium bovis. 

New Legislation

Just a reminder that both Surgeries are covered by the new no smoking legislation so I would ask you not to smoke on the premises.

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