A survey reported in Countryfile tonight shows that the badger cull is working (1 Viewer)

[IAN JAMES THOMPSON]

A controversial report reported in Countryfile last Sunday evening, shows that in areas where there have been badger culls taken place, that turberculosis has been reduced in cattle dramatically. I’m not sure weather to believe this or not
Ian.

 

[Mayo Corncrake]

TB tested cattle in republic of Ireland for 14 years. After culling of badgers bTB would generally decrease. bTB often returns though as badger populations return and you get a lot of mixing of different populations of badgers.

 

[Dry ice]

A controversial report reported in Countryfile last Sunday evening, shows that in areas where there have been badger culls taken place, that turberculosis has been reduced in cattle dramatically. I’m not sure weather to believe this or not
Ian.

You might find this paper of interest , it describes the pathology of tb in both badgers and cattle,

http://www.bovinetb.info/docs/johngallt_b_review9-04.pdf

It explains why badgers with tb are so effective at spreading tb, and in contrast how difficult it is for cattle to spread it.

The graph (fig 5) showing the results of the Thornbury trial may persuade you of the effectiveness of badger culling to control the disease.

Countryfile covered the issue of biosecurity around farm buildings but failed to point out the difficulty of biosecurity for the 6+ months when they are grazing in the fields.

 

[Dry ice]

When one considers that reactor cattle are culled, not because they have tb, but because they have been exposed to it, in hot spot areas they are tested at six monthly intervals, and herds under tb restrictions cannot sell animals to other farmers. All farmers must test cattle that are to be sold to other farmers, and, if clear, then have sixty days to move them. In conjunction with the pathology of tb described in the link in my previous post, one would expect the spread of tb by cattle to be very rare indeed.

These observations, by Professor Ian Boyd, Defra Chief Scientist, suggest that this is indeed the case.

http://tacklingbovinetb.tumblr.com/post/47025052679/the-story-of-bovine-tb-the-attack-of-the-clones

when one drills down in to the details of this clonal complex within Britain one finds an interesting pattern. There are different forms of bTB in different areas. Put simply, if bTB could talk it would probably have regional accents. This implies, for example, that bTB from Somerset doesn’t mix much with bTB from Cornwall. Now, if you are in to bTB like I am this is just fascinating. It also an encouraging signal that cattle movement controls to prevent the spread of bTB are working, as otherwise we would probably a lot more mingling of the bTB strains and an eventual blurring of regional distinctions. That there are still such thick ‘accents’ between regional variations suggests some success in containing them within their regions.
The emergence of the SB0140 clonal strain in the British Isles is a bit of a conundrum. Could it be the result of selection caused by the kind of test we use to determine whether cattle have TB? To test cattle for TB, we use a strain of TB (called AN5) that was gathered from an English cow in the 1940s. While this test is still perfectly adept at picking up SB0140, we have found through our testing that the original strain, AN5, has been successfully eliminated from English cows. It is interesting that while this strain has died out, SB0140 has survived and flourished. This leads me to an intriguing hypothesis; is SB0140 specifically adapted to survive and thrive in badgers?


Those areas with ‘regional accents’ have not altered, except to expand, in the 40 years since they were first identified. The Spoligotype (tb strain/regional accent,) map of GB shows that in hundreds of cases, the strain of bTb in both badgers and cattle is unique to their indigenous area, with only very isolated cases of a 'foreign' spoligotype appearing out of its own patch. If cattle to cattle or cattle to badger spread were significant, then, as Prof Boyd points out, one would expect the map to be very blurred indeed.

 

[MJB]

Those areas with ‘regional accents’ have not altered, except to expand, in the 40 years since they were first identified. The Spoligotype (tb strain/regional accent,) map of GB shows that in hundreds of cases, the strain of bTb in both badgers and cattle is unique to their indigenous area, with only very isolated cases of a 'foreign' spoligotype appearing out of its own patch. If cattle to cattle or cattle to badger spread were significant, then, as Prof Boyd points out, one would expect the map to be very blurred indeed.

That's a very useful post as a clarifying summary. It brings one thought to mind:

Given that many studies have shown that the severe culling or removal of a predator in one area from the food chain accelerates movement of individual predators from outside that area into it, would that severe cull or complete removal increase the risk of 'foreign' spoligotypes migrating effectively into that area?
MJB

 

[Dry ice]

That's a very useful post as a clarifying summary. It brings one thought to mind:

Given that many studies have shown that the severe culling or removal of a predator in one area from the food chain accelerates movement of individual predators from outside that area into it, would that severe cull or complete removal increase the risk of 'foreign' spoligotypes migrating effectively into that area?
MJB

Until the early 90s we had tb under control:

http://www.vet-wildlifemanagement.org.uk/index.php?option=com_content&task=view&id=14&Itemid=28

Despite Prof Boyd’s observation that ‘cattle movement controls to prevent the spread of bTB are working, as otherwise we would probably a lot more mingling of the bTB strains and an eventual blurring of regional distinctions’, tb hotspot areas are still expanding, and unless the disease is addressed in badgers, these areas will eventually merge with each other anyway.