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In a previous blogpost we looked at the statistics of bovine TB or bTB and came to the conclusion that the disease is spreading and in some counties here in the Midlands spreading very rapidly.

Which brings us to the point where the government has announced two pilot culls of badgers to control bTB, one of which will take place here in the Midlands.

Cattle and badgers all carry and transmit bTB so it sounds obvious that we need to control both to get a grip on the disease. As we saw previously we certainly slaughter enough cattle with bTB so logically the badger must be culled too. Otherwise you're just tackling half the problem.

Turns out though the wrong sort of cull makes the problem worse. We discovered that during an earlier pilot of badger culling in the region if you cull badgers when you detect bTB in a herd of cattle the infection spreads. The thinking is when you cull a family group that includes infected badgers any you miss wander off and infect other setts in areas outside the cull. Scientists call this the perturbation effect.

So the new trial culls take account of what we have learnt about the perturbation effect. They are taking place over a much bigger area and have been chosen to have features such as motorways and rivers along the edges. These measures should reduce the impact of the perturbation effect itself.

But that's not all that's changed in the cull. Other variables have been significantly altered and this leads to criticism that it's impossible to know if this new cull will work or even make things worse.

To which the government and others say in effect, "we know it works we're just trying to find a real world method we can apply" And that's true, the earlier trial did show a cull to remove 70% of badgers reduces the disease by around 16%.

As far as the government is concerned the right sort of culling works and this latest pilot cull is more concerned with whether or not those concerned can remove enough badgers in a humane and cost-effective way.

After six weeks of culling the data will be analysed and if the conditions have been met then up to ten other culls will be given the go ahead across the country. In each case the cull of badgers will be repeated every year for at least four years.

Farmers are paying the costs of this cull and must put up 125% of the estimated price. That extra 25% is to pay for cage trapping of badgers, as was used in the earlier cull, if it's found "free shooting" isn't effective.

So we come back to the motto of this blog, "science is the answer". Where does that leave us in this case?

The nightmare scenario is of course that the cull makes things worse, but that this takes some time to become apparent, a variation on what happened before. Given the differences in method between the last pilot cull and this one that is possible. It is also possible that the cull has no impact which could lead to calls for the complete eradication of badgers in hotspot areas rather than 70%.

But the government is convinced the cull will reduce bTB without spreading it further and do so in a humane and cost effective way. It can point to the results of the earlier trial and what they learnt from it and say the science has allowed them to improve the new cull and mitigate these problems. As a fallback if it's found "free shooting" is not as effective as hoped then farmers will have to go back to cage trapping. And pay for it.

And while culling any animal population is not a decision to be taken lightly badgers are not endangered and join a long list of animals we already cull for any number of reasons.

As ever with science we continue to gather the data and will have a definitive answer after a few years. Sometimes with science you have to wait.