Saturday, October 07, 2006

Rosie's 2 + 2

In our posting below we gave links to the a paper described both as 'American', and 'New', which amongst other more sensible conclusions, like tackling Tb in all species, hypothesised that cattle could give Tb to badgers. As we pointed out, the chief contributer was none other than our own Rosie Woodroffe, now perching in Californian sunshine, and various members of the UK Tb 'magic circle'. But as its main conclusions were drawn from UK Rosie's RBCT dispersal exercise, then it was neither 'American' nor 'New'.

Dr. Woodroffe said;
"Repeated badger culling (this would be in the RBCT badger dispersal exercise) in an area, is associated with increasingly prevalence of M bovis infection in badgers."

If, as with RBCT cage trapping on 8 nights only, a badger group is fractured, then territorial scrapping occurs as they regroup. So nothing new there, except that our Rosie appears to think she and the ISG have discovered something novel.

She continues:
"Additionally, we show that suspension of cattle Tb controls during the nationwide epidemic of FMD which substantially delayed the removal of Tb infected cattle, was associated with a widespread increase in the prevalence of M. bovis infection in badgers".

This was the sentence onto which Trevor Lawson and the Badger Trust hooked their tentacles.

But the BBC website went further:

"Culling badgers should be a low priority for curbing cattle tuberculosis", according to a scientist advising the British government. New research by Dr Rosie Woodroffe and colleagues suggests that culling raises the rate of TB infection in badgers. It also demonstrates that cattle infect badgers with the bacterium.

"This research has 2 important conclusions," said Dr Woodroffe, a researcher at the University of California in Davis and a member of the UK government's Independent Scientific Group on Cattle TB."The first is that it shows for the first time that there is substantial transmission of TB from cattle to badgers, whereas in the past it's been assumed that didn't happen," she told the BBC News website. "The 2nd conclusion is that repeated culling increases the prevalence in badgers -- each time you cull, it goes up and up."

After a suspension of culling in the Krebs areas during the FMD outbreak of 2001, Tb infection in cattle went up, and that was expected due to lack of routine testing, but also a rise was recorded in tb infection in badgers. And that, according to Rosie Woodroffe, was most definitely not expect. Why, one wonders when with incomplete culling over 8 nights with cage traps, that very scenario was predicted by badger experts prior to the start of Krebs is hard to understand - but we digress:

"We saw across seven study areas a rise in the badger TB prevalence -- almost a doubling," said Dr Woodroffe. "No other explanation fits the data."

"Across the 8 years of analysis, culling was also associated with increased TB in the badgers; areas which had received 4 culls saw a doubling of the rate. What appears to be happening is that badgers move more freely and more widely in culled areas, increasing contact with each other and with cattle." Not really. It was the ones left behind by the RBCT, you remember, the up to 80 percent not trapped, or released by activists, that were on the move.

Predictably, animal welfare (sic) groups greeted the study enthusiastically. "This research confirms beyond doubt that cattle are the main vectors of bovine TB, readily infecting badgers and other cattle," said Trevor Lawson of the Badger Trust. "
Source: BBC, 2 Oct 2006 [edited]<http://news.bbc.co.uk/2/hi/science/nature/5401266.stm>

Hmmm. "No other explanation fits the data" the lady said.

Our Rosie seems to have ignored all evidence to the contrary, and assumed that the RBCT actually culled badgers. All of them. And more than that, they stayed culled. And by that I mean, the farms 'Krebbed ' on those 8 nights, once a year (if they were lucky) remained a badger-free zone. The reality is far from that as we have pointed out. The last thing the RBCT did was a clean sweep of its target animals. So why should anyone - except Dr. Woodroffe it seems - be surprised if "everytime you cull, it [Tb infection in badgers] goes up and up.."

No it does not. If a whole social group is taken out at the same time, then social disruption or peturbation as it is known, is nil. But do a half cocked job as described by the leader of one of the Wildlife Teams undertaking the work, .http://bovinetb.blogspot.com/2006/03/robust-basis-of-krebs.html, and of course the infection 'goes up and up.' Badgers that are left, up to 80 percent of the target, are frantically travelling to locate missing relatives and territorial scrapping spreads Tb. The result on cattle herds, even ones with no bought in cattle, was reported here http://www.farmersguardian.com/story.asp?storycode=4294.

But as well as the total shambles of the RBCT in practise, the Foot and Mouth epidemic of 2001 should not be assumed to be limited in its effect, to 11 million dead animals - or as Dr. Woodroffe would have it, the lack of tb testing of remaining cattle..

It is impossible to remove 11 million mainly grazing animals out of their environment, very quickly and at a time of premium activity and growth (February - August) when their dung, placentas and even stilborn offspring were then unavailable for use by other animals and insects within the wider ecology. And to put the agricultural practises which supported those 11 million dead cattle, sheep and pigs into a state of suspended animation for over 12 months, and expect the ecological balance of thousands of acres to remain constant.

Well if the good doctor has missed the point, at least English Nature recognised it, producing a 100 page pdf file: http://www.english-nature.org.uk/pubs/publication/PDF/enrr430.pdf in which even half way through the carnage, they try to assess the effects of the lack of grazing livestock, coupled with over- grazing and poaching in other areas, on the British country side.

They comment:
"Changes in the structure of livestock farming, for instance changes in stocking levels or type of livestock, and changes in land use where livestock farming ceases as a result of the FMD outbreak are likely to be the major long term and most complex influences on biodiversity"

Their map chart on page 12, shows that loss of livestock, change in livestock farming and/or a change of land use where livestock farming ceases post-FMD as impacting every type of habitat listed. Their cover sheet FMD map shows that outbreaks were concentrated in areas now covered by red Tb parishes on Defra's latestTb incidence map - which in itself is an amplification of the original 7 or 9 hotspots, described by Prof. Steve Harris, ten long years ago.

Without livestock, and in particular cattle dung pats, the whole pyramid of 'ecological life' changes. Beetles, flies and worms are not there, so their predators including bats, songbirds and badgers, have nothing to eat, and are forced to forage elsewhere - or die.

A double whammy occurred where animals on short term grazing were impounded, and their pasture land became overgrazed at best, and a mud bath at worst. This too affected the insect life, and thus levels of wildlife predatory on 'normal' farming practise, and over a wider area.

But Rosie's 'no other explanation fits the data" totally ignores the thousands of acres of livestock free land, abandoned to rank long grasses, no corn crops and no agricultural practise at all, and conversely, areas so heavily stocked as to be unavaibale for predatory use by any other species, and their unfortunate occupants subsequently offered a 'welfare cull'.

Rosie's observation of the increase of infection after suspension of RBCT culling during FMD within the badgers was correct - her conclusion as to its cause, in the opinion of the Wildlife teams and farmers unfortunate enough to have taken part, was not. Perturbation was the result of that shambles, and the same scenario was repeated as Britain's countryside was systamatically de-populated of the very animals on which badgers are parasitic for their survival. Cattle and sheep, and the husbandry which surrounds them.The influence of FMD is certainly important, but the assumption that the suspension of some cattle testing during it, led to 'infected cattle giving Tb to badgers' is lightweight shot in the dark. Adding 2 + 2 and making 8.

1 comment:

George said...

'No other explanation fits the data"? – what rubbish. Not only are there a large number of factors involved – many associated with the huge ecological change when the major herbivores are suddenly removed from the scene – but the cattle have to be capable of spreading the disease. It might be expected that the lack of testing would lead to rampant disease in the cattle with many lung cases, who would then spread it to the rest of the herd, leading to huge numbers of reactors in herds, then to wildlife and other domestic animals in the vicinity. But I understand that was not what was found when testing started again. OK, more reactors were found – but that was to be expected. In fact, the numbers filled the gap caused by the Foot and Mouth Disease almost exactly. Rampant disease? Massive spread within herds? No, that was not found to any greater extent than would normally be found. So the source for all these infected badgers was just not there, it seems.