I wrote this report as an essay for my English Higher exams. I tried to simplify the mountains of information out there on this subject and I hope I have succeeded and you will find this informative.
The
media’s coverage of the badger cull is normally attached to a picture of an
angry celebrity or a sad farmer- the former opposed to the cull, the latter,
supportive of it. Both have been informed by scientists that their case is
valid and the real facts sway heavily in their favour. How can two groups of
intelligent people come to such different conclusions, particularly in the
field of science? I set out to investigate this topic, setting aside the
emotional issues and looking at the science of the subject. I was hoping that
the answers would be, like the badgers in question, an obvious black and white.
This
has become a hotly debated issue in the UK- an e-petition to the government
against the cull, submitted in September 2013, had collected 303,929 signatures-
a record for the largest number of people ever to sign a government e-petition.
(1)
Bovine
tuberculosis (bTB) is an infectious disease of cattle and one of the biggest
challenges facing the cattle farming industry today, particularly in the west
and south west of England. It is caused by the bacterium Mycobacterium bovis (M. bovis), which can also infect
and cause TB in badgers as well as many other mammals. (2)
Bovine
TB can come as a crippling financial blow to farmers. His farm in Somerset has
just reopened after a 6-month lock-down triggered by one of his cows testing
positive. "Until the disease has really progressed in your cows, there are
no visible signs," he says, which makes it a serious problem for cattle
farmers in the UK and elsewhere
“Our results indicate that while badgers contribute
significantly to the disease in cattle, cattle-to-cattle transmission is also
very important in high incidence areas and is the main cause of disease spread
to new areas.” (3)
(4)Bovine
TB can come as a crippling financial blow, says James Small. His farm in
Somerset has just reopened after a 6-month lock-down triggered by one of his
cows testing positive. "Until the disease has really progressed in your
cows, there are no visible signs," he says, which makes it a serious
problem for cattle farmers in the UK and elsewhere
This phenomenon was dubbed the
"perturbation effect". Infected badgers in the cull area fled to the
surrounding unculled zone, taking TB with them. So strong was the perturbation
effect that the increased herd losses in the peripheral area effectively
cancelled out gains within the culled area. In fact, the RBCT's 2007
conclusions suggested that just 14
herd infections would have been avoided after a
sustained badger cull covering 1000 square kilometres of farmland for five
years.
But continued monitoring of the same
sites where the RBCT took place has changed the picture, strengthening the
justification for culling after all.
Christl
Donnelly at Imperial College London was a
member of the team that performed the original 2007 analysis and has
periodically collected data from the study region since 2006. Between 2006 and
2011 there were 28 per cent fewer TB infections there than might otherwise have
been expected. What's more, the boost seen in TB levels in the unculled outer
ring did not persist. In fact, between 2006 and 2011 there were 4 per cent
fewer TB cases than expected within the outer ring
Armed
with the new data, scientists advising the UK government concluded that culling
over four years in a hypothetical area of 150 square kilometres - killing an
estimated 1000 to 1500 badgers - could achieve a net reduction of herd
infections of around 16 per cent within nine years. This, they calculated,
equates to preventing 47 out of 292 TB herd infections that would result in a
farm being locked down.
John Krebs at the University of Oxford
headed the team that did the original RBCT trials. He sees problems with the new
conclusions: "The pilot cull is flawed because it aims to remove 70 per
cent of badgers without an accurate estimate of the starting number."
Krebs and 31 other prominent scientists wrote to DEFRA this week arguing that culling would
actually risk increasing cattle TB, and calling for a rethink. "Badgers
are only part of the problem - about 50 per cent of new TB cases are
cattle-to-cattle," says Krebs. In Ireland,
though, culling badgers has had an effect. The Irish government began a culling
programme there in 2002 following a trial which found that herd outbreaks of TB
were between two and 25 times less likely in culled than unculled areas (Preventive
Veterinary Medicine, doi.org/b33wc7).
"There's been progress in the last
10 years that wasn't seen in the previous 30, and the difference is the
badger-culling programme," says James O'Keefe, a spokesman for the Irish
agriculture ministry.
DEFRA is also working on a more
long-term solution that all sides in the debate support - vaccinating cattle so
they cannot spread TB between themselves or pick it up from badgers. "We
have proof of principle it works, but not approval," says Nigel Gibbens,
the chief veterinary officer at DEFRA.
There is a big hurdle to vaccination.
It is illegal in Europe, because it is very difficult to distinguish vaccinated
from infected animals, as both produce identical antibodies to the TB bacteria.
DEFRA has developed a test that will do just that but it will be a long road
proving to the European authorities that the vaccine and the test work, then
persuading them to change European law to allow vaccination. (4)
(5)
Evidence from other
countries with bovine TB, such as Australia and New Zealand, shows that TB in
cattle cannot be controlled without also controlling the disease in wildlife that act as a reservoir for the disease.
Research in England has
demonstrated that cattle and badgers transmit the disease to each other. It
also showed culling badgers leads to a reduction of the disease in cattle if it
is carried out over a large enough area and for a sufficient length of time.
This application of what we
have learned from careful scientific experimentation includes measures to
counteract some of the problems that have been highlighted by those studies.
Culling will only be permitted in areas sufficiently large that the impact of
any short term increased incidence of disease - from disruption to the badger
population - is outweighed by the long-term benefit in the culled area. Farmers
proposing to cull must also apply management measures to reduce the risk of
spread of disease between badgers and cattle, and culled areas must be planned
to reduce as much as possible the likelihood, or impact of, increased movement
of badgers. We have made it clear that these culls alone will not solve the
problem of TB in cattle. There is no single solution and they represent part of
a comprehensive package of measures that the government is taking to arrest the
increase in new bovine TB cases.
In high-risk areas herds are
tested annually and any cattle that test positive are removed. Herds with
infected cattle are tested more frequently until all the cattle that test
positive have been removed. Restrictions on cattle movements have been
strengthened to reduce the chance of disease spreading from cattle to cattle, and
we continue to look at ways we can improve cattle TB testing.
Farmers are taking measures
to stop badgers from contacting their cattle and are beginning to assess the
risk of buying cattle from herds that are at high risk of being infected. While
these measures are helping to slow the advance of bovine TB, without further
action they alone cannot solve the problem.
The
government has funded, developed and licensed an injectable badger vaccine, but
it has its limitations. Badgers need to be trapped before they can be
vaccinated, and the process will need to be repeated annually for many years,
which makes it extremely expensive to use. The vaccine is not 100% effective in
preventing TB, and is ineffective in animals that are already infected with TB and that will
continue to spread disease. So current vaccines will not be as effective as
culling in reducing spread of the disease from badgers to cattle. We are
planning to invest a further £15.5m in vaccine development over the next four
years to continue to develop both an oral vaccine for badgers, which may be
cheaper and easier to use, and a vaccine for cattle. But it will be several
years at least before either of these methods are available and we cannot
afford to wait for them.
(6)
Britain's top
animal disease scientists have launched a devastating attack on the government's "mindless" badger
cull, accusing ministers
of failing to tell the truth and demanding the immediate abandonment of the
killings. The
government's own chief scientist has refused to back the killings.
However, the scientists reject the idea of scientific support for the
cull, which could wipe out 100,000 badgers.
Another signatory, Lord Robert May, a former government chief scientist
and president of the Royal Society, said: "It is very clear to me that the
government's policy does not make sense." He added: "I have no
sympathy with the decision. They are transmuting evidence-based policy into
policy-based evidence."
A Defra spokesman said:
"The leading experts Defra brought together in April 2011 agreed that the
evidence shows that culling done in the right way can reduce the spread of the
disease to cattle, with benefits remaining for many years. The culling policy
has been developed to maximise the benefits shown in previous trials, and to
minimise the impact of badgers spreading disease beyond the cull area by
including hard boundaries such as motorways and rivers."
But scientists say the two-page document produced by the April
meeting does not support the cull. Professor Rosie Woodroffe, of the Zoological
Society of London, said: "The document simply does not endorse the
policy."
The scientists, whose letter is also being sent to Paterson, claim
scientific opinion in the UK is overwhelmingly against the cull. "I just
don't know anyone who is really informed who thinks this is a good idea,"
said Professor John Bourne, who led the decade-long trial.
(7) The scientist whose research is being cited by the government to
justify its plan to cull badgers in England has described the scheme as
"crazy".
The plan is based on the results of a nine-year trial which showed that
the spread of the disease could be slowed slightly if more than 70% of badgers
in an area could be eradicated. If it was less than 70% - the spread of TB to
cattle might even increase. But the scientist who carried out the study has
told BBC News that these pilot studies make no sense. Lord Krebs, who is one of
the government's most respected scientific advisers, said that the Department
for the Environment, Food and Rural Affairs (Defra), which is administering the
scheme, has no way of knowing how many badgers there are in the area, so will
not know when they've killed 70% of the badgers in the area. "I would go
down the vaccination and biosecurity route rather than this crazy scheme that
may deliver very small advantage, may deliver none. And it's very hard to see
how Defra are going to collect the crucial data to assess whether it's worth
going ahead with free shooting at all," he said.
(8) The most
important scientific evidence comes from the Randomised Badger
Culling Trial (RBCT), also known as the Krebs trial, which ran from
1998 to 2005. It was funded by the Government and compared the effects of
proactive, reactive and no culling across ten sets of sites
in England.
Lord Krebs, who designed the
RBCT, concluded that that “culling is not a
viable policy option”.
"First,
while badgers are clearly a source of cattle TB, careful evaluation of our own
and others’ data indicates that badger culling can make no meaningful
contribution to cattle TB control in Britain. Indeed, some policies under
consideration are likely to make matters worse rather than better.
"Second,
weaknesses in cattle testing regimes mean that cattle themselves contribute
significantly to the persistence and spread of disease in all areas where TB
occurs, and in some parts of Britain are likely to be the main source of
infection. Scientific findings indicate that the rising incidence of
disease can be reversed, and geographical spread contained, by the rigid
application of cattle-based control measures alone."
The conclusions of the RBCT
are available to download below, contained within the Final Report of the
Independent Scientific Group on Cattle TB - 'Bovine
TB: The scientific evidence.'
Badgers typically live in
social groups of four to seven animals with defined territorial
boundaries. Culling disrupts the organisation of these social groups, increasing
the risks of disease transmission as shown below.
This is known as the
'perturbation effect'. The Independent Scientific Group on Cattle TB
concluded in its final report (2007) that it was "unable to conceive of a system of culling, other than the
systematic elimination, or virtual elimination, of badgers over very extensive
areas, that would avoid the serious adverse consequences of perturbation".
Patterns of direct and indirect contact between
cattle and badgers naturally infected with tuberculosis, Drewe et al. 2013
This study looked at how bTB
might be transmitted between badgers and cattle. It found that direct
contact between badgers and cattle at pasture, often thought to be the main
route of transmission, was actually very rare.
Biosecurity
Effectiveness of biosecurity measures in preventing
badger visits to farm buildings, Judge et al. 2011
Relatively simple practical
measures can reduce some of the potential for contact and disease
transmission between badgers and cattle.
This study found that simple
exclusion measures (sheet metal gates, fencing and feed bins) were 100%
effective in preventing badger entry into farm buildings, as long as they were
appropriately deployed. Furthermore, the installation of exclusion measures
also reduced the level of badger visits to the rest of the
farmyard.
Badger vaccination
BCG vaccination reduces risk of Tuberculosis
infection in vaccinated badgers and unvaccinated badger cubs, Carter et al. 2012
Vaccination of badgers with
BCG appears to be beneficial in at least two ways
This paper states that:
"Vaccination
of badgers with BCG appears to be beneficial in at least two ways: by directly
reducing the TB burden in vaccinated individuals and by indirectly reducing the
risk of unvaccinated cubs acquiring infection, most likely through a herd
immunity effect on this susceptible component of the badger population.
Indirect ‘protection’ bestowed upon juveniles before they become accessible for
vaccination themselves could be an important contribution to the success of
vaccinating wildlife."
9. I have managed some of the
highest-yielding dairy herds in the world with consistently high levels of
hygiene and disease resistance. Meticulous biosecurity and sympathetic animal
husbandry are the key to stamping out TB in cattle, not shooting British
wildlife.
Farmers vilify badgers but
TB is mainly transmitted cow to cow. So the solution to eradicating TB lies
with farmers themselves who must accept responsibility for a disease that is
all too easily spread back and forth within and between herds due to poor
management, lax biosecurity and substandard animal care. A slow response in
tackling the disease compounds the problem, which can therefore soon reach
epidemic proportions. I have seen it many times with mad cow disease, foot and
mouth and now bovine TB. Alas, the farming industry prefers to scapegoat
badgers rather than tackling these fundamental problems.
Water troughs are a
reservoir for TB because they are rarely cleaned out. It's not uncommon for
trough water to be left stagnating through the winter, collecting dead birds,
rodents and various bacteria, only to be drunk by cattle in the spring. Badgers
also use these troughs but it's unfair to isolate badgers when the culprit is
the bacteria soup itself. Making troughs badger-proof is not rocket science,
but more fundamental is the adoption of better hygiene standards by the
agricultural industry.
Lax biosecurity on farms is
also a major factor. Cows infected with TB should be quarantined immediately,
but they rarely are. Every farm should have isolation areas to separate these
animals and prevent cross-infection, but they rarely do. Biosecurity is often
ignored by farmers and
poorly enforced by Defra.
Infected cows can be left unquarantined on farms for weeks. Before a single
badger is shot, the farming industry should get its house in order.
We also need to improve
cattle welfare. Farm animal stress caused by pain and suffering can reduce an
animal's immunity and make it more susceptible to diseases like bovine TB. On
too many farms, there are high levels of lameness, mastitis and rough animal
handling. The average incidence of lameness in our national herd is a shameful
22%.
This is lazy husbandry. We
have a wealth of veterinary knowledge to eradicate disease, and in countries
with more advanced control measures there are very low incidences of bovine TB.
10. Bovine TB was virtually
eliminated in the UK by the late 1960s without any badgers being killed, and
the disease stayed at that very low level for 20 years. The NFU (but not all farmers) has called
for this ineffective and cruel mass slaughter because it needs an excuse for
why the incidence of bovine TB has risen since then. The NFU would rather blame
badgers than admit that increasingly intensive farming practices make animals more susceptible to
disease.
Richard Mountford
Development manager, Animal Aid
