The long discussed trial culls in Somerset and Gloucestershire are now underway, with Somerset starting last week and Gloucestershire this week. There has been much debate in the media, with a majority of public opinion against the culls, but the level of detail in that debate often leaves something to be desired. Bovine TB is a terrible disease, both for cattle and badgers, so how have we come to be in such a controversial mess? And is the cull either necessary or desirable? Well I am going to sit on the fence to an extent, but I do think that it is not as bad as many make out. Indeed the issues are all around animal welfare, rather than nature conservation.
So looking at the problem, badgers do give TB to cattle, and vice versa; indeed TB is also found in a range of other wild British mammals. The best solution would be to eliminate TB form all populations. The proportion of TB given to cattle by badgers is not known, although estimates range from 20% to 50%. And also, the incidence of TB in cattle has risen sharply in recent years, with 38,000 cattle being slaughtered last year alone.
In the 1960s a programme of slaughter dramatically reduced the incidence of TB, with only 235 cattle being slaughtered by 1986. So why is that not working now? Well one reason is that the badger population has increased dramatically in the meantime, with an estimated population of 900,000 now, compared with perhaps 50,000 thirty years ago. Increasing animal welfare concerns led to the introduction of the 1992 Protection of Badgers Act, since when the population has increased steadily. What is the right size of badger population, and should we control wild animals at all? Well the natural balance has long since been upset, be it the introduction of several deer species and grey squirrels (generally not good for trees!), or the removal of our major predators such as wolves and brown bears, several centuries ago. Unless we go back to a completely wild unfarmed landscape, then active management, including culling the top of the food chain, is going to be part of a sustainable system.
But badgers are not the only vectors of the Bovine TB, and the transport of cattle around the country is another big factor. The disease spread dramatically following restocking after foot and mouth disease. The reasons for this being, at least in part, that the current test for TB is not 100% accurate, so diseased animals have been moved before they showed any symptoms. Hence the correct calls by many animal welfare groups for better biosecurity measures in farming.
To be fair to Defra, a fairy comprehensive plan to rid England of bovine TB within 25 years has been set out by Environment Secretary Owen Paterson. The strategy covers action in areas such as disease surveillance, pre- and post-movement cattle testing, removal of cattle exposed to bTB, and tracing the potential source of infection and wildlife controls including culling and vaccination trials. It also focuses on the development of new techniques such as badger and cattle vaccines and new diagnostic tests that could one day offer new ways of tackling the disease. In other words they are looking at all aspects of control and funding a range of research and trial projects. About time too, as the problem has not been solved, or gone away in the thirty years I have been working in woodlands. So a pat on the back for being willing to tackle the problem!
The trials have been criticised for either being unlikely to work, or not going to work. Earlier trials failed because they were undertaken in small areas, which just encouraged badgers to move into cleared areas, thereby spreading the disease more. This is why these trials are covering two larger areas. Proponents of the cull acknowledge that they will need to kill 70% of badgers in the trial areas, to achieve a reduction in TB, estimated at 16%. Less than that and the cull is increasingly less likely to have an effect. Badgers are being shot by trained marksmen, so the chances of injuring, but not killing, an animal is small. Opponents of the culls argue that the16% reduction is uncertain, and may not work. Supporters point out that the culls are trials, and other control measures are also being trialled.
So what about vaccination? There are trial vaccinations of badgers, being funded by Defra, and indeed a number of Wildlife Trusts and the National Trust are engaged in this process. Its more expensive, and has its own problems, for example relying on natural deaths to remove infected animals from the badger population, and needing repeating over several years. Again, vaccination is likely to be one part of a solution, as is being actively trialled.
Defra are also spending £9.3M on research and development of a cattle vaccine over the next 4 years. A big problem with the cattle vaccine is that the current test for TB in cattle can not distinguish between an infected cow and an immunised but healthy animal. So a better test is needed there, which in turn could provide better biosecurity and less cattle to cattle transmission. Here the gamma interferon test is more accurate, and is being used as the basis for more research.
So, the situation is complex as well as controversial. I believe that some of the nature conservation organisations are taking public stances based as much on what their members want, and animal welfare, rather than conservation. But I do want to give the Government credit for taking a holistic approach, and not doing the easy thing. Providing the trials are treated as trials, with proper review of results, and provided all avenues continue to be explored, then we should accept and support these difficult decisions. A major reduction in TB, and even elimination in the long term, can only be good for farming, good for cattle and good for our wildlife.
Photographs by Wildstock