Badgers & Bovine TB

By Carole Youngs

cattleWith the two planned pilot badger culls in Somerset and Gloucestershire having been postponed last autumn, what are the facts about Bovine Tuberculosis (bTB) as it affects cattle, badgers and other species, and is there a viable alternative to culling wildlife? This article describes the author’s experience of vaccinating badgers on her smallholding and discusses options for the future.

When the two pilot cull areas in Somerset and West Gloucestershire were first announced in January 2012, we realised that our small farm would be affected. We have an active badger sett in our orchard and, although we don’t keep cattle, we’re acutely aware of the bTB situation in the UK and its devastating effect on dairy and beef farmers. Our neighbour kept cattle on an adjacent field for many years, and, having repeatedly tested negative for TB, we concluded that the badgers occupying ‘our’ sett were very likely free of the disease too. On this basis we decided to vaccinate the badgers, which, following a detailed survey by experienced fieldsmen, and delays due to the appallingly wet weather, was completed in July 2012. To ensure that all generations are fully protected, vaccination will be repeated annually for the next 4 years.

Badger Vaccination

  • badger-vaccinationThe vaccine used is BCG – the same vaccine used in humans; a special licence must be obtained for its use in wildlife
  • Vaccination will not cure a badger already infected with bTB
  • Vaccination can reduce the amount of infection spread by an infected badger through its faeces and urine, but there will still be spread via aerosol effect
  • Vaccination has been shown to protect naïve youngsters in a sett from contracting the disease
  • A vaccination programme must run for 5 years to be effective
  • Vaccination must be carried out by trained field staff, licensed by Defra

Wettest Summer on Record, London Olympics & Too Many Badgers

Inevitably there were outcries against the proposed badger cull, but ultimately it was a bizarre combination of circumstances that caused the planned cull to be postponed at the end of October. The washout summer had hampered the progress of the essential surveys to assess the badger population; the scientific advisors’ view was that 70% of badgers within the cull zones should be removed for the strategy to succeed. Then, the need to avoid negative publicity during the Olympics further delayed the start of the proposed cull. But ultimately it was the higher number of badgers than originally thought were present in the cull areas, together with the imminent onset of the badgers’ breeding season that caused the cull to be postponed. Defra, together with the NFU, who are responsible for coordinating the planned cull, confirmed their intention to re-instate plans for the cull during 2013.

So perhaps now is the time to review and clarify what we know about the confused situation of the link between badgers and bovine TB, and to examine possible solutions.

“There are three kinds of lies: lies, damned lies and statistics” (attrib. Mark Twain)

The proposed badger cull has created deep divides in the population: those in favour (broadly, the NFU representing the farming community, though not all support the cull by any means), and those against (in particular, the RSPCA and a diverse range of animal rights groups). There is little common ground between the two sets of opinions. Both ‘sides’ are vociferous in defence of their viewpoint, each propounding scientific evidence and statistics (and often the same statistics, presented in different contexts) to support their particular stance. Sadly, this has only served to further cloud the facts and science concerning the link between badgers and Bovine TB (which infects dairy and beef cattle, and has recently been found in domestic goats and alpacas, as well as badgers, deer, wild boar and foxes). Therefore, for the sake of even-handedness, I will try to avoid quoting spurious statistics in this article!

Why is bTB considered to be such a problem?

Worldwide, tuberculosis (TB) is one of the most common infectious diseases in humans: it’s estimated by the USA Center for Disease Control and Prevention that one third of the human population suffers from the disease at any one time. TB is one of the greatest causes of death in people suffering from HIV. In industrialised nations, human TB is rare due to the pasteurisation of milk and the culling of infected cattle herds.

The TB vaccine (BCG) does not always protect people from contracting TB, and whilst there are treatments for the disease, worldwide there are an increasing number of multidrug-resistant cases each year. In the UK, milk has routinely been pasteurised since 1935; this kills the organisms (if present) that cause TB and thus protects humans. During the 1950s compulsory bTB testing of cattle was introduced, and by 1960 all cattle in the UK were tested at least once, with all ‘reactors’ – those that tested positive – culled.

In 2012, 35,000 cattle were slaughtered as bTB reactors or ‘direct contacts’. Source: AHVLA

Why not just vaccinate cattle?

This is considered by most, whatever their viewpoint, to be the “Holy Grail” – effective and acceptable to all … except to the EU, on the grounds that it is currently impossible to conclusively differentiate a vaccinated cow from one that is carrying the disease. To allow the UK to trade on this basis would place other TB-free member states at a disadvantage. It is currently estimated that it will take up to 10 years to develop an acceptable vaccine (or political stance!) that will overcome this problem.

What other methods of control can be used?

All cattle are currently subject to a very strict regime of periodic bTB testing and rigorous movement controls to prevent the spread of disease to non-infected herds. Infected individual cattle, and sometimes, entire herds, are culled. In January this year, these rules were further strengthened, with the introduction of compulsory pre-movement veterinary testing at the farmer’s expense.

It is in no one’s interest for these controls to be breached, but, inevitably there are occasional rogues who attempt to break the rules – the penalties are severe, and can include imprisonment of the offender.

Biosecurity Measures

gloucester-cattle-2Prevention of nose-to-nose contact between cattle and wildlife is important (if somewhat difficult on a farm with possibly miles of boundaries), and there are numerous bio-security measures that farmers can employ to reduce cattle to wildlife contact, including carrying out a land survey to map badger setts, latrines and runs – then take measures to exclude cattle from these areas; use raised feed and water-troughs designed to prevent use by badgers; install low-level electric fencing around cattle sheds, feed stores and silage clamps, and keep a closed herd.

Any attempt by an individual farmer to depopulate a badger sett by any means would be both illegal, and might possibly worsen the impact of bTB through the effect of ‘perturbation’, where the badgers are disturbed and move to a new, previously uninfected, area. Perturbation is also cited as a potential damaging outcome of any attempt to remove badgers by culling.

Is there a way forward?

Combating this disease has got to be a multi-pronged effort. Farmers can improve biosecurity wherever possible, as well as maximising the herd’s health to promote a strong immune system – although even herds with the highest health status can still succumb to the disease. Scientists are working towards more effective vaccines, including a cattle vaccine that can be differentiated from the actual disease during testing. And finally, the reservoir of disease in wildlife must be reduced to prevent the risk of transmission to cattle, or other farmed species: in-field testing and selective culling of diseased animals would be a very positive way forward, and vaccination of healthy wildlife most certainly has a role. Defra acknowledges that “Badger vaccination could help reduce the prevalence and severity of bovine TB in a badger population and thereby reduce the rate of transmission to cattle”.

 


 

If you’d like more information on this very difficult subject, I recommend the following sources:

www.defra.gov.uk

www.tbfreeengland.co.uk

www.rethinkbtb.org

www.southwest-tbadvice.co.uk

www.brockvaccination.co.uk

 

Share