As the thorny question of targeted badger culling refuses (quite rightly) to lie down, Veterinary Times last week published a thought provoking Point-of-view, from T.O Jones, MBE, BVSc, CBiol, FBS, FRCVS on how this may be achieved.[ sorry no on-line link, so we'll summarise.]
The piece begins by describing the TB situation in West Wales, which has led to the Welsh Assembly's intention to pioneer a targeted cull of badgers in that area. We have covered some farmer's stories from this area here (Trioni Farms) and here (Cilast herd) But how will Wales actually carry out the deed? So much red tape is wrapped around this animal, that cage trapping and shooting appear to be favourite - not ideal, in fact far from it, which is why Mr. Jones puts his eloquent pen to paper.
He points out that this method is unlikely to achieve even 80% of the target group at best, with the RBCT's halo of 'peturbation' and spread of bTB by distressed untrapped badgers as a result. (We continue to attribute this 'perturbation' phenomenon to the Badger Dispersal Trial, and that alone, because it was not evident in previous AH culls.) And of course, there has to be a 'closed season' from February to May to avoid leaving cubs to starve underground by shooting lactating females. All in all, a pretty poor effort if one is serious about disease control.
The use of carbon monoxide (CO) Mr. Jones suggests, is worth looking at, with a machine which uses it for rabbit control being tested in Australia. He then asks if this is not available in the UK, in cylinders? or as solid (concentrated) frozen CO?
"Many humans would opt for an unpremeditated, painless euthanasia during sleep as their exit of choice. Pure unadulterated CO poisoning might well be acceptable for such an approach in badgers."Also a possibility is Carbon dioxide (CO2) and possibly pure nitrogen. Pointing out that:
"Mobile on-site nitrogen generators are used in the oil industry, but are presumably too large for the Welsh countryside. But would it be worth purpose building a small one? One litre of liquid nitrogen produces 683l of gaseous nitrogen at normal atmospheric pressure and could have a place in euthanasia apparatus."As Mr. Jones points out, badgers obligingly live in their setts during Defra's working hours and during prolonged cold periods may not emerge for several weeks when they are said to be in a state of 'torpor'. "Could they not", he asks "be euthanased while in 'torpor', during this period?"
"Collection and disposal of carcases would not be problematic [ with gassing] A 100 per cent cull, with no perturbation could be anticipated. Setts could be blocked or collapsed to hinder recolonisation in the sure knowledge that no live animals were present."Much of this thought provoking essay, calls on other industries to throw their respective hats into the ring and offer ideas for practical administration of a humane gas to these subterranean animals.
The delivery of gas into badger setts has been trialled both by Defra and Porton Down when with their very own unique buckets and spades, they built an artificial sett - each. And despite howls from the Badger Trust, gas was available in adequate quantities at all parts of the sett - once they'd blocked up the entrances.
Mr. Jones argues that a targeted cull of badgers in bTB hotspot areas, followed by a gradual infiltration with vaccinated, healthy badgers would deliver the nirvana of healthy badgers, healthy cattle (and cats, dogs, alpacas, llamas, goats, pigs ..... ed)
"Our country has an established meline TB problem - some badgers suffer from TB and spread it to healthy badgers. A lingering death from progressive TB in a proportion of infected badgers is painful. What action is suggested? Doing nothing, and allowing TB to spread through the UK badger population is not necessarily a position of moral superiority"
4 comments:
To cage trap the 80%, they are more likely to be the healthy ones, hold them for three days as with cattle while they are tested, that way the healthy ones can be released (and, or vaccinated as needed), and those that fail the test are disposed of.
Then in the mean time, gas the set to clear the ailing ones that are left in the set.
Well Fred, it's a thought. You said:
"... hold them for three days as with cattle while they are tested, that way the healthy ones can be released (and, or vaccinated as needed), and those that fail the test are disposed of."
Agree that first past the post - or in this case into the trap - are likely to be the dominant scent markers, but 'hold them' ???
How? Where? In the cage? For days? I don't think so.
VLA Weybridge have a badger pound, which we are told has reinforced concrete walls 15 feet deep - to keep the blighters in. And test them, how?
The old Brock blood test is good on a positive, but dangerously weak on a negative reading, meaning that over 60 percent of badgers testing negative will have TB. (Accuracy is only 47% on a negative result) Bloods need taking to a lab for assays to be read. And Defra seem extraordinarily reluctant to get a handle on PCR, which could offer pen-side (or sett-side) results within an hour, including finding m.bovis in the air and bedding material of an infected sett.
"Then in the mean time, gas the set to clear the ailing ones that are left in the set."
If one badger in a sett has TB, it's a fair assumption, confirmed by PQs that given the humidity and close encounters within the sett, that others are infected.
We would favour using the cattle test results on a wide scale, then fieldcraft to map which setts are giving problems. It doesn't have to be 'wipe out' and in some cases an infected sett will have territory across farms other than the one on which it is located.
Gassing with carbon dioxide is a non-starter; all mammals (ourselves included) are sensitive to carbon dioxide levels at quite low concentrations; a lungful of even 1% CO2 produces a strongly painful choking sensation. Gassing with pure nitrogen works on most mammals, but naturally aquatic animals such as mink are distressed by this, because they have oxygen-level sensors in addition to the CO2 sensors. It is therefore worth experimenting with captive badgers to see if they can detect low oxygen levels before any gassing takes place since inappropriate use of nitrogen will cause avoidable suffering to the badgers.
Carbon monoxine by contrast is a very different proposition. It is odourless, doesn't trigger the CO2 sensors of mammals, and is deadly in quite low concentrations; a concentration of 5% in air is cited as a useable concentration for euthanasia where rapid knock-down and death is needed; a much lower concentration would be effective on badgers as they'd be exposed for a much longer period. CO also has the advantage of being easily produced, and not horribly toxic in the environment as HCN is.
For preference, I'd prefer not to have to do any of this. This option has, however, been stolen from us by the most incompetent government in recent centuries; the ludicrous vaccination programme won't do anything, the cage trapping won't do anything and really massed gassing of infected settes is the only resort left to us.
Thankyou for that comment, Dr. Holdsworth. Appreciated.
We hear that as cattle slaughterings rise, this government rub their hands in glee as less methane is expelled into the air. Obviously imported beef and milk comes from cattle which have different biological functions.
They have however forgotten the spillover of this highly infectious bacteria into other species, many of which have close contact with their owners...
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