The Badger Cull

There has been a lot of talk recently of the badger cull taking place in south west England and a lot of animal rights activists have been having hissy fits over the destruction of our native and protected species, the badger (Meles meles). For once it appears that scientific evidence is on their side, so why is the cull taking place?

What is actually happening?
Badgers are being culled (shot, preferably in the head,) in two main areas of England; West Gloucestershire and West Somerset, as part of a trial to see if getting rid of the badgers has any effect on the levels of bovine TB (bTB) found in the area.

Why?
Bovine TB is a chronic infectious disease affecting a broad range of mammalian hosts including humans, badgers and cattle. Bovine TB is usually transmitted to humans via infected milk, which in the developed world is a rare occurrence due to the fact that milk is pasteurised. TB testing in cattle also means that any cattle harbouring the disease are immediately destroyed to prevent it spreading. Cattle TB can also be passed on to humans via aerosols but this is very rare and can be prevented by not letting cows cough or sneeze in your face.
Other than possible health risks to humans the second (and probably more relevant) reason for trying to control bTB is that it causes serious health problems in cattle. Tens of thousands are killed every year which can be shattering for farmers economically and emotionally. It also costs the government and the taxpayer millions of pounds a year (government doc.).

“We shall not be mooooved!”

Why is the cull happening now?
The current cull is taking place as a further study after the Randomised Badger Culling Trial of 1997. The RBCT was done in the areas of England with the highest levels of bovine TB. The cull was carried out in 30 areas which were grouped into ten sets of three. In the first area badgers were killed every year (proactive culling), the second area badgers were only killed on or near farms that had recently contracted cattle TB (reactive culling), and in the third no culling took place but the levels of bTB were monitored. The trial was concluded in 2003 with three observations:

Observation 1
Reactive culling caused around a 20% increase in bovine TB incidence
Observation 2
Proactive culling reduced cattle TB inside the tested area but increased it on neighbouring land due to the fact that killing the badgers disrupted their social groups and caused surviving animals to move out of the area spreading the TB further afield.
Observation 3
It took four years of killing badgers before there was an overall drop in cattle TB and this drop was small and expensive.

These observations led to two main conclusions:
a) That although badgers did contribute to cattle TB, badger culling made “no meaningful contribution to cattle TB control” and in some cases actually make the situation worse.
b) That cattle themselves contribute significantly to the persistence and spread of TB and in some cases may actually be the main source of infection due to weaknesses in cattle testing regimes (Badger pdf).

The previous government, in light of this information, decided that a badger cull would not be worth doing as there was “no guarantee of success” and there was “potential for making the disease worse”. However the National Farmers Union strongly (and understandably) disagreed and stated that this conclusion was an “abdication of responsibility”. Despite the fact that culling had been trialled and was seen to be unhelpful in combating TB and in some cases made it worse, the current Minister was desperate to be seen to be doing something to help the farmers. So as farmers could do the shooting themselves and the cull was therefore cheaper than funding the cattle and badger vaccination programmes, the south west of England cull was given the go-ahead (house of commons pdf.).

Why they think the cull might work
In other developed countries such as America, Australia, New Zealand and Ireland, cattle TB is just as much of a problem, however the difference is that in those countries the wildlife source of TB is being culled. White tailed deer and water buffalo in America, the possum in Australia and New Zealand and the badger in Ireland, and it is the latter that is the most relevant according to the Environment Minister Owen Paterson. As the number of cattle needing to be destroyed per year in Ireland has decreased by around 6000 in the eight years since the cull was implemented he thinks that that culling badgers in England will work just as effectively. (Video of Paterson)

However according to this slightly suspicious graph I found on the internet, the number of cattle having to be destroyed because of TB in Ireland was already decreasing by the time the cull was in place, and in fact increased the year after it started. It has taken ten years for the number of cattle being destroyed to decrease to half its original number, and only eight of those years had a cull implemented (graph website)

Why I think the cull is pointless
• Culling the badgers will either cause an increase in bTB incidence in the south west, or an increase in the surrounding areas due to the emigration of the badgers.
• The method for killing the badgers (shooting by farmers), is different to the cull done in 1997 meaning that the results may be different. As the original cull trapped the badgers first, injured badgers could not move to other areas. However the current cull does not include the trapping of badgers meaning that non-vital injuries could cause an increase in the spread of bTB to nearby areas.
• Badgers can be vaccinated and research is being done into oral vaccines for cattle and badgers.
The most effective way of vaccinating badgers in the short term is with the human TB vaccine, M. bovis Bacille Calmette-Guérin (BCG). However this vaccine generally doesn’t work unless it is live and as live vaccines are killed off by stomach acid, oral distribution of the vaccine, which would be the most cost and time effective method, is not applicable as of yet. The development of a successful oral vaccine would depend on it still being live once consumed by the badgers as well as when contained in the bait, which is why it is unlikely to be developed until at least 2015 (Defra).

quit badgering me

All in all it’s a bit of a muddle and from the devastating effects bTB has on the farming community, to the horrible consequences of the cull on badger populations, it is hard to decide who is in the right. It’s at times like these that I look with admiration to Wales. For, despite announcing an order to destroy badgers in 2011, they later stated that they would review the scientific evidence and have since begun a project of badger vaccination (bva website). So, from a scientific point of view, at least we will be able to review the bTB situation a few years down the line and compare it with the levels of the disease in Wales and will therefore be able to deduce which form of “treatment” is better. TB or no TB, that will be the question.