Monday, July 16, 2007

Krebs v. RBCT

It has become apparent through comments posted to the site that our criticism of the RBCT, (which we reserve the right to refer to as a 'badger dispersal trial'), has rattled not a few cages. But it is only in latter years that the trial has been referred to as the 'RBCT' in total, rather than the 'Krebs Trial' or the 'Krebs RBCT'. The author of the trial has just melted away, and we wondered why this should be.

One of our contributers met Professor Krebs some time ago, when he expressed concern at the way 'his' trial was being carried out. Contributers to this site saw first hand what happened on farms within the trial areas, and operatives and managers concerned in its implementation have also voiced concerns. But how does that compare with the recommendation protocols offered in 1997 by Professor, Sir John Krebs?

We have now obtained sight of a copy of the proposals from the trial's originators, and in them, Professor Krebs explains why they were important to his trial's outcome.

P126 In explaining the efficacy of previous policies:

7.8.3 The gassing and clean ring strategies, in effect, eliminated or severely reduced badger populations from an area and appear to have had the effect of reducing or eliminating TB in local cattle populations. The effect lasted for many years after the cessation of culling, but eventually TB returned.

7.8.4 The interim strategy, introduced following the Dunnet report, is not likely to be effective in reducing badger-related incidence of TB in cattle for the following reasons:

(i) The policy involves removing badgers from a limited area (the reactor land or the entire farm suffering the herd breakdown if the former cannot be identified) ; but social groups of badgers may occupy several setts covering more than one farm.

(ii) Partial removal of groups could exacerbate the spread of TB by peturbation of the social scructure and increased movement of badgers.

(iii) There is no attempt to prevent recolonisation by badgers of potentially infected setts; even if infectivety in the setts is not a problem, immigrant badgers may bring new infection.

In addition, the current operation of the interim strategy involves a delay (27 weeks in 1995) to the start of the removal. The average period from the herd breakdown to the completion of the removal was 41 weeks in 1995.

7.8.5 In common with the clean ring strategy and the live test trial, the effectiveness of the interim strategy is further underminedf by the failure to remove lactating sows which may also be infected. We recognise that culling lactating sows has a welfare cost in terms of cubs left in setts, but this needs to be balanced against wider animal health and welfare considerations for both cattle and badgers.


So, the originators of the Krebs trial protocol recognised that gassing and clean ring strategies worked for several years by reducing or eliminating Tb in cattle, and conversely they considered the 'interim' strategy to be ineffective for the following reasons: that it split social groups of badgers, thus exacerbating peturbation and territorial social structure. It also 'failed to prevent recolonisation of potentially infected setts'- (except by placing 3 sticks across the entrance) - and it allowed lactating sows to offer transmission of Tb to their cubs. It was also very slow in delivering follow up action to a herd breakdown.

In another part of the proposals (7.8.9) Professor Krebs reiterates some key features which he said were likely to influence the effectiveness of any reactive strategy:

(i) The size of the area cleared, (including the extent to which this takes into account badger territory)

(ii) The efficiency of the badger removal operation (to ensure all infected badgers are removed and minimise any problem of peturbation associated with partial removal of social groups)

(iii) The prevention of recolonisation for a sufficient period.



One would assume from that critique that all these failures of the interim strategy and recommendations for the efficacy of a new ££multi million trial would be taken note of by the operators of the RBCT. But in that assumption, one would be quite wrong. Wildlife Manager , Paul Caruana's experience of working under ISG instructions gives a vastly different picture of the methodology employed. And this is backed up by comments on the site from others involved in trial operations.

The original Krebs methodology:

7.8.14 We suggest that the most appropriate Reactive strategy would be to target culling at social groups where a badger-attributed breakdown has been identified. This would involve removing all badgers, including lactating sows, from all social groups with territories including the breakdown farm (or reactor land if this can be rigorously identified). There should be sufficient follow up to ensure that every member of every social group which could have caused the initial breakdown has been removed.

7.8.15 Ideally recolonisation of setts should be prevented for a period of time under the reactive strategy. This would be costly. We therefore consider that costs should be balanced against potential benefits in deciding whether this should be included in the detailed experimental design. In any event given the lack of data on recolonisation times, we recommend that further research should be done on this in areas subject to both reactive and proactive control strategies.

7.8.17 The Proactive strategy would involve total removal of complete badger social groups from localised areas at high risk of breakdown, before breakdowns. This strategy would require regular monitoring and also revisiting after two or three years to deal with renewed badger populations.


Other proposals explored in the Krebs document include stop-snaring as as alternative to trapping, taking into account efficacy, cost and welfare considerations. Farmer particiaption and MAFF involvement in the trial is proposed and Krebs predicted a 20 per cent reduction in Tb over five years.


To reiterate what actually happened:

* That the RBCT attempted badger removal operations using cage trapping for 8 nights only, during their infrequent visits. There was significant interference, particularly during the first 4 years of operations, and many removals were attempted during winter months, when little badger activity above ground is expected.

* No follow up occurred at all. No checks on setts and no confirmation of complete clearance of a social group. No culling at all took place in 2001, because of biosecurity imposed by FMD. Thus all areas within the trial, both reactive and proactive went at least 2 years between these incomplete removals. Some, including our contributers, experienced 3 years of such peturbation chaos.

* Badger social groups were split, and during later years boundaries of trial areas were changed to accomodate this.

* No action was taken at all to prevent recolonisation of setts thought to be cleared.

* A closed season operated from February to May to allow lactating sows to rear cubs.

* There was absolutely no involvement with participating farmers, or local MAFF officers.

As well as a rebranding of the 'Krebs' RBCT, the ISG are at pains to point out that their aim was never to 'cull all the badgers' as proposed by Professor Sir John Krebs. This particular protocol is now downgraded to a mere 'population reduction'. And then there is the ISG's unique and notorious 'edge effect'; a phenomenon which if the original methodology proposed by Professor Krebs had been observed, may not have been evident at all.

The original Krebs' prediction of a 20 percent reduction in incidence was correct, but unfortunately by not following Professor Kreb's protocol with regard to implementation of the trial, the trial operators achieved exactly the results that Krebs described as 'unlikely to be effective' during the interim strategy in his report of 1997.

15 comments:

Jim said...

The more I learn about what was already known, the greater my astonishment at the utter waste of time, money and cattle lives (badger lives too) that the RBCT represents. As you say, "badger dispersal trial" would be a better description.

a different anon said...

As I've said previously, perturbation is caused when either part of OR a whole social group are taken out leaving badgers in bordering social groups to wander more freely into the empty space (and hence infect cattle in that space). One could argue it's MORE likely to happen when you remove an entire social group because there are NO badgers left to make the territorial boundaries. Bearing this in mind, please can you explain how more efficient culling would have prevented the rise in incidence seen in parts of the trial?

Matthew said...

A different anon:
Of course any species, including badgers will spread out and fill a space created by the absence of others.
You ask how taking out a 'whole group' will prevent peturbation. It is our understanding from other students of badger behaviour, that badgers on the outside of a clearance, will of course gradually make inroads towards the centre of such a vaccuum - if they need the area to source food, and as old boundary scent markings dissipate.

New boundaries will be defined by the first dominant scent marker to claim his territory, as we we told in our posting of April 2005;
http://bovinetb.blogspot.com/2005/04/biological-fence.html

Adult badgers from separate groups, this research suggests, are unlikely to cross this new scent line. So no territorial scrapping, but a gradual redefining of bigger boundaries for each group making ingress.

Our point of the thread was to question what Professor, Sir John Krebs understood about the previous clearances of infected badger populations, and what worked and what did not.

It is our opinion, that he and his team understood a lot, and advised accordingly. But how Bourne and the ISG acted on that advice was a very different matter.

For sure the ISG's notorious 'edge' effect perturbation does not seem to have been a problem for any other clearance, - as Professor Krebs pointed out. And the clever thing is to make sure that badgers so moving into a vacated area are a) uninfected with Tb so not infecting cattle co-habiting there, and b) protected from sett born infection when they do recolonise.

We have no more time for hoooooge hard edge area clearances aka Bourne than we suspect do you. They do work, but are not necessary if knowledge previously employed is used to best practise, combined with up to date technology.

Bourne seems to want to kill more and more cattle, but quicker. And that won't work either, as we pointed out in the posting below.

But neither does leaving an infected reservoir to spread that infection amongst other groups, and to other species as it has done outside the RBCT areas since 1997.

Matthew said...

Jim;
The parliamentary questions / answrs which form the basis of this site were not a political stunt. They were a fishing expedition to extract what was known already about the epidemiology of bovine Tb in both badgers and cattle, and the effect of habits of both species on transmission.

The 'gold standard' of epidemiology is the 'Evans postualtes' (formerly the Koch postulates of the 1890s).
And by early 2004, the questions showed that most of these postulates had been fulfilled. So you are quite correct, the RBCT was a prevarication, not a necessary progression of knowledge at all.

a different anon said...

Matthew said "And the clever thing is to make sure that badgers so moving into a vacated area are a) uninfected with Tb so not infecting cattle co-habiting there, and b) protected from sett born infection when they do recolonise.". I think you might want to replace the word "clever" with "currently impossible". Taking out badgers means that other badgers come into the vacated space. It's not about territorial scrapping, it's about badger movements. Given the prevalence of infection in the badger population, clearing whole social groups of badgers will inevitably mean that some of the incoming are infected and will infect cattle in that area. As I've said on a previous post, to which there was no reply. Ignoring the results of the trial is naive to say the least.

Matthew said...

A different anon;
said "Ignoring the results of the trial is naive to say the least"

Which trial?
This posting explored the protocol proposed by Professor, Sir John Krebs in 1997 for the latest effort by the ISG. It is quite clear from his recommendations that to avoid peturbation (and thus increased spread of disease), many things should be done and conversely, other things should not.
It is equally clear that these recommendations were not followed, by the ISG in the current trial, with entirely predictable consequences.

Smaller, more targetted but intense clearances over a longer (than 8 nights) time frame would appear from past policies to have a far better effect as Professor Krebs explained in 1997. A policy which was supported by Professor Steven Harris in his 'alternative to the RBCT', which we explained in July 2004, here:
http://bovinetb.blogspot.com/2004/07/krebs-there-was-another-way.html

The RBCT showed how NOT to carry out a cull, from information which was known already : not that it should not happen at all.

a different anon said...

you're right when you say that it showed how not to carry out a cull - an experiment isn't always there to show how to do something but also that something isn't the right thing to do. But you miss my point which is: more intense culling would not have prevented the perturbation which caused the rises in incidence that were seen. Therefore your constant harping about how they should have culled more intensively is completely irrelevant as it wouldn't have actually improved the result in terms of lower cattle incidence.

Matthew said...
This comment has been removed by the author.
Matthew said...

A different Anon said;
".. more intense culling would not have prevented the perturbation which caused the rises in incidence that were seen."

We did not miss your point.
We did not agree with it.
The results from Thornbury, the 'Clean ring' strategy and Professor Harris' proposed alternative to the Krebs RBCT do not support your conclusion. And from our posting here, even Professor Krebs realised how not to do his trial.

You are saying that peturbation occurs if any or all of a group are removed, I think.
We agree that of course another group would gradually expand territory to fill that gap, but we also pointed out from a badger expert’s extensive research, that the first dominant scent marker to define that new territory would prevent territorial scrapping and bite wounding.

Is it possible that when an entire social group is removed then the next badgers moving quickly into the area may be 'dispersers' from neighbouring groups? Is that why a more prolonged culling stratgy, even on a small scale worked? And after this, the recolonisation is from a healthier, more stable group? Just thinking aloud.

Past policies of large scale of intensive clearance (Thornbury) worked extremely well with "no other contemporaneous change identified that could have accounted for the reduction in [cattle] Tb incidence within the area” [Hansard 24thMarch 2004 Col 824W [157949]. The Thornbury clearance, (begun when cattle incidence reached 5.4 percent) was not so very long term either, starting in December 1975, and ending in August 1976. After which badgers were able to recolonise clean ground, their numbers recovering to pre cull levels, but the area remained clear of Tb in cattle for in excess of 10 years.

Smaller clearances in response to Tb breakdowns, which targetted setts (and groups) implicated in a farm or group of farms breakdown during the ‘clean ring’ strategy were also successful, and from contributers to the site who were involved, lasted about 6 / 8 weeks.

We do wonder if provided the group is left intact, or conversely removed completely the ‘peturbation’ effect is overstated? When a food source is available, Prof. Roper's research showed up to three groups sharing feed during night filming in Glos. cattle sheds. And we have told on this site of 84 badgers crossing a small field nightly, on their way to be served peanuts for the benefit of paying viewers in a Staffordshire wildlife park. That would be around 8 groups on Harris methodology, would it not?

CSL’s hand fed Woodchester badgers often make forays into adjacent territory: “Temporary and permanent dispersal from one group to another occurs regularly” Hansard: 17th March 2004. Col 274W [157988].

The point we are trying to make here is NOT to remove the strongest, leaving the sick, old and weak behind as the RBCT did – at least for its first 4 years. WLU operatives have commented on this site that after that the ISG did listen – a little bit – and refined trapping protocol accordingly, with better results.
Thus we cannot agree your conclusion that better culling would have made no difference to the results of the RBCT. That’s hypothetical and not born out by the examples above.

Experience has shown that even smaller clearances are successful if carried out thoroughly. And last years’ PCR trial from Warwick found about 64 per cent of the setts in the Glos. hotspots showed negative for Tb, so any movement of badgers from these would be without immediate risk to cattle, or to other badgers.

a different anon said...

Finally we have what could potentially be an interesting answer!

I am still confused, however, as on an earlier post you agreed that there were only two options: Matthew said "Your final sentence is probably correct. Depressing but correct. A 'nationwide cull' or one which identified only infected badgers (groups?)."

And now we have a different argument for a culling strategy which might work. (If true, of course we have seen examples of the matthews and jo misrepresenting statistics and selectively quoting from scientific papers so let's not get too excited - just thinking aloud).

But let's assume it's true - what are you going to do with this information and theory? Not keep to yourself surely? What are you doing to get this theory to the govt either yourself or via the NFU or similar?

Matthew said...

A different anon.
you say;
"Finally we have what could potentially be an interesting answer!"

We have not altered tack at all on this site. We do not favour wipe out - of any species, just tuberculosis.

We cannot see the sense in criticising the basis or conclusions of the RBCT, and then trying to cherry pick bits of it, while expecting government to ignore its less palatible proposals.

You say you are confused by a previous answer:
In the interim and final ISG reports, Bourne intimated that a bigger cull with 'hard' boundaries would be more successful. It would, but the boundaries and scale would be so big as to be unworkable - in our opinion. That is not to say that some groups / politicians may not grab this as a possibility.

What they ignore is the ISG's seductive prediction of a drop in cattle Tb of 15 percent if more cattle measures are adopted, over and above preMT, now into its second year.

The only way this will happen is if gamma and more frequent testing (difficult if you are aleady doing it every 60 days) takes out 15 percent more cattle. How killing more cattle but faster can answer the problem, while leaving a reservoir behind in badgers, we explored in our post of July 1st.
http://bovinetb.blogspot.com/2007/07/condemned-to-repeat-past-mistakes.html

But we are aware that any such proposal on badger control could inevitably have extra cattle controls bolted on, despite the past futile experience which we have described above.
However from past (bitter) experience, government have a nasty habit of dividing their agreement packages, prior to implementation.

We think what this boils down to, is to understand how badger ecology - away from the well drained, well fed population at Woodchester - operates, and use this to 'manage' a now widely infected population in areas of endemic tb. And for several years now, that is what the authors have tried to do.

Cattle testing on a regular (annual) basis of course is part of this, but in isolation from clearing infection from wildlife reservoirs, it has been shown to be totally ineffective.

It is futile to repeat past mistakes; we must learn and move on from strategies which proved succesful, using up to date technology as back up.

As to whom that message is directed and 'what are we doing to publicise it', well anyone reading the site should by now be aware of our balance. And we would point out that for 10 years, eminent professors, experienced veterinarians, badger experts and farmers have attempted to avail government with their various very knowledgeable points.

G'ment preferred the prevarication and predictable chaos of the RBCT.

a different anon said...

Your last two paragraphs are a copout. It sounds as though you're saying there's now point telling the govt because they won't listen. Or is it that you're happy to write things on the safety of a blog where you can say anything you want without a heap of experts pulling your arguments apart?

If you truely want to do something to help, there are many more constructive ways. Or maybe, as other anons have said, you like a good rant on a blog. In which case, I'll happily leave you to it.

Matthew said...

A different anon sid;
"Your last two paragraphs are a copout."

And the others?

"It sounds as though you're saying there's now point telling the govt because they won't listen. Or is it that you're happy to write things on the safety of a blog where you can say anything you want without a heap of experts pulling your arguments apart?"

No, and no. We have tried for 10 years to bring sense to this polarisation - and failed, and that includes directly to government or their agencies.. When herds like those of our contributers suffer prolonged Tb breakdowns, and 'no bought in cattle' are implicated, there is nothing any 'expert' can say to avoid the conclusion that another source of bTb is responsible.

"If you truely want to do something to help, there are many more constructive ways."

Such as?

Anonymous said...

Talking to a listening Government?

The 10 years New Labour regime has generally demonstrated that it both knows very little of the British countryside and cares even less about its indigenous population, its traditions and its way of life. The debate regarding bTB illustrates this perfectly

Remember how it started?

The very first action that the New Labour administration took on gaining power in May 1997 was to stop the, then already planned and about to be implemented, culling of some 900 badgers (30 days – 30 badgers / day) in North Staffs. Ask Elliot Morley!

Then began the negotiations between Prof Krebs & MAFF (remember Nick Brown) as to what the Krebs Report should contain and recommend. That took six months to agree! The recommended compromise was then again compromised between MAFF and Bourne in true Hutton-esque style. You know what I mean – all the evidence obviously points to one thing and - blow me down - it turns out to be the opposite – Iraq turns out to be the fault of the BBC and after 16 months investigation by the Police the CPS says – ‘you may have found a list of 16 millionaires - every one being offered Peerages for loans and donations but where’s your evidence’?

You will recall the Political Animal Lobby (PAL) and its associate organisation IFAW (not a charity) and its donations to the Labour party of more than £1.25 million. It is said by them that know that at the time of the donation £1 M bought from New Labour whatever you wanted – in this case the banning of hunting and the ‘no culling of badgers’.

Remember both Tony Banks & Elliot Morley (MAFF Minister) were funded by IFAW – remember Cherie Blair’s (step) sister worked for IFAW. And – bless him – Tony Banks was a prime mover in the 1992 Badger Act.

Over the 10 long years New Labour has manipulated the Civil Service and attempted to control communications. DEFRA scientist no longer speak ‘science’. Rather their job is to make it accommodate policy - he who pays the piper calls the tune – ‘We’re not culling badgers – that’s policy! So what’s next best?’ Hence we have long-respected badger / bTB expert scientists being quoted as saying ….. (within the unstated policy) “we should address the cattle problem first” – when previously he said – “cull the badger”.

So we have had the The Trials – a gradual – over 10 years of cock-up upon cock-up; each problem – FMD, agro-terrorists creating havoc interfering with the RBCT - each element being allowed for and underpinned by the statistical witchcraft of the ISG that puts Harry Potter to ‘shambo’.

FMD? - no problem we can adjust for that! 60% (whatever) of traps interfered with – no matter – we can adjust for that! Three years to ‘react’ to reactive culling request – don’t worry we can adjust for that! Etc etc etc

There have been a few hiccoughs for New Labour with the House of Lords. It was happy to use the Parliament Act to ban hunting with hounds.but nothing else deserves even the threat of using the Parliament Act not an education issue, not health, not crime, not terrorism, nothing else!

Thus the issue of bTB in cattle and badger (etc) then is not one of science or animal welfare but simply one of electoral / political / moral corruption – and it’s very difficult to beat that. So you can see what mountains the bTB farming community have got to move! And although the CLA, NFU, etc are for culling the badger – this further motivates the NL culture machine to fight badger culling – ‘who wants to be on the side of the CLA and NFU?’ - in the attempt to save their political seats!


As to bTB – the issue is very simple – no badger – no bTB in cattle. As to the RBCT – it has really taught us nothing we didn’t know already – and that includes the subject of ‘perturbation’ – an issue Prof Krebs warned Prof Bourne about. Indeed – in a so-called ‘scientific’ trial – surely the true measure of success is the occurrence or not of ‘perturbation’ – any perturbation suggests failure – none suggest success! Thus Professor Bourne failed! QED.

at length

Peter Brady SETT

Matthew said...

Anon 12.49 - SETT

Unfortunately you are spot on. And while a peeceee diet of 'badgers don't suffer' and 'cattle get killed ultimately' gets fed to a gullible public the scenario will continue.

Tuberculosis control is not about badgers or cattle. It is about the control of a serious zoonosis to protect the health of other mammals, and ultimately human beings. That it is a sneaky, long term condition is no excuse for ignoring its risks, or governmental responsibilities for its control and eradication.