Vet speaks out in favour of Pembrokeshire badger cull trial to eradicate bovine TB (From Western Telegraph)

Vet speaks out in favour of Pembrokeshire badger cull trial to eradicate bovine TB

4:00pm Saturday 10th April 2010 in

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Paul Rodgers, a practising vet with more than 30 years’ experience, tells the Western Telegraph about his experiences tackling bovine TB on the ground. “When I started in practice in 1978 TB had nearly been eradicated. Since the 1990s, when control of badgers was stopped, there has been a steady increase in TB. The intensive action pilot area has given me hope that we can see the end to this terrible disease in west Wales.

With some trepidation I agreed, last Monday, to speak to a meeting of Pembrokeshire Against the Cull to explain my views on TB control and the work that farmers and their vets in the area are already doing to stop TB from getting into herds. Measures that most of the audience, who I suspect were not farmers, are not aware of.

Successful TB control can be compared with a three legged stool: testing and removal of infected cattle; control of movement from infected herds; control of wildlife. Like a stool all three legs need to be in place.

These days too much of my time as a vet is spent testing for TB. There is a lot of debate and misunderstanding about how good or accurate the current TB test is.

Some say that the tests do not pick up all infected cattle, and at the other end of the spectrum, that too many cattle that are not infected are taken for slaughter unnecessarily.

The accuracy of any test is judged by how sensitive it is (how good it is at finding disease) and how specific it is (how good it is at correctly identifying non-diseased animals as uninfected). Unfortunately, if a test is made more sensitive it becomes less specific.

In areas where there is no external source of TB such as Scotland or Cumbria, the tests used in the UK are sufficiently accurate and work well. If bovine TB was only present in cattle, we could eradicate it by testing alone. But because it is also present in badgers in areas such as west Wales, testing is not enough.

Herds in the pilot area are to be subject to stringent cattle movement controls and more frequent testing.

From May 1st, most herds will require two annual TB tests. Farmers have also had the first of a series of biosecurity visits by their own vets to help them reduce the risk of their herd getting TB by changing farming practice. Areas looked at include: contact with neighbouring herds; cattle introduction; slurry management; access of badgers into buildings and feed stores.

Unfortunately, the main site of TB infection in badgers is the kidney, so contamination of pasture with highly infectious urine is common and it is very difficult to eliminate this risk when cattle are grazing.

Since 1975, a series of trials have provided compelling evidence that removing badgers will reduce TB in cattle. In 1998, the Randomised Badger Culling Trial looked at the effect of culling badgers with proper experimental control areas (areas which had no culling). There was a significant reduction in new herd breakdowns within the cull areas, partially offset by an increase in surrounding areas due to the much vaunted social perturbation effect.

However, soon after the end of the trial the perturbation effect disappeared, whereas the benefits persisted for more than two years.

There is a misconception about what a vaccine can do. Generally, vaccines prevent disease, not cure it, so a badger infected with TB will remain infected, even if it is vaccinated.

A badger vaccine has only just received a licence which will allow Defra to trial whether it is actually practical to trap and inject thousands of badgers. If the vaccine works, it will be many years before there will be a decrease in cattle breakdowns.

The present crisis is such that we do not have time for a vaccination policy in infected areas to work. When a practical oral vaccine is developed, it may be possible to keep uninfected badgers healthy, but that is still years away.

I look forward to a time when I will not have to tell another farmer that his best cow has to be killed and when many thousands of badgers no longer die a slow, unpleasant death due to TB.”