Following Princess Anne's comments on Countryfile last Sunday, Dr Chris Cheesemen sets out the case against the use of gas in culling badgers.
Princess Anne’s suggestion that if we want to kill badgers the kindest way would be to gas them was guaranteed to provoke controversy. The record needs putting straight.
The unfortunate side effect of the interview has been to focus the debate on the method of culling rather than on the assumption that we have to kill badgers to tackle TB in cattle (the science says not).
So let's deal with this irrelevant issue of gassing badger setts once and for all.
Back in 1982 I was asked to visit the Chemical Defence Establishment at Porton Down to witness the results of experiments designed to improve the efficiency of hydrogen cyanide (HCN) gassing of badgers, the then preferred method of culling. What I saw was truly shocking.
HCN was believed to be humane in action, with animals lapsing into unconsciousness and either dying, if the dose was lethal, or recovering without ill effect from a sub-lethal dose.
I watched videos of badgers retching and vomiting while making distress calls. When asked what I thought, I said that gassing with HCN was clearly inhumane and should be stopped immediately, and so it was.
Work was also undertaken to try to explain why badgers frequently dug their way out of setts that had been power gassed with HCN. Whole setts were excavated, with convoluted tunnel systems hundreds of metres long, and it was discovered that in the blind ended tunnels gas concentrations fell well below the lethal dose required to kill badgers.
Apart from the need to demonstrate the humaneness of any gas, whether it is carbon monoxide, carbon dioxide, or any other candidate gas, there are many other difficulties associated with gassing:
- As with the recent free shooting it is indiscriminate – both healthy and infected badgers will be killed.
- Protected non-target species such as otters and polecats sometimes occupy badger setts.
- Badger setts are often in inaccessible places like very steep wooded banks, cliff edges, caves or tin mine shafts.
- The complex structure of setts will make it difficult to achieve the lethal concentration of gas required.
- There are safety implications for operators and the public.
- It is unlikely to be cost effective.
- We have no knowledge of the potential negative impacts on the spread of TB in both badgers and cattle, such as the “perturbation” influence already demonstrated with trapping.
- Perhaps most importantly, there would need to be an expensive trial to establish whether gassing badger setts is an effective way of controlling TB in cattle.
To use the well-worn cliché, it’s a no-brainer.
Cattle measures are the key tools for controlling bovine TB, as Wales has demonstrated by nearly halving the number of cattle slaughtered in just four years from 11, 671 in 2009 down to 6,102 in 2013. This was achieved without any badger culling.
The obsessive preoccupation with culling badgers must be replaced with a determined effort to drive down the cattle-to-cattle spread of TB. If there is still a need to tackle the disease in badgers when this has been done, vaccination offers the only viable option.
Dr Chris Cheeseman is a badger ecologist.