Sunday, May 21, 2006

Defra to 'test' Dutch tuberculin.

The sudden drop in numbers of cattle slaughtered as bTb reactors prompted a flurry of reaction from industry and media, if not from Defra, when figures were published in the second week of May. (see post below)

Farmers Guardian reported the story and gave more information:

Entitled "Dutch tuberculin under scrutiny as TB figures fall", their article continues:

"Defra vets are investigating whether a switch in the type of tuberculin used to test cattle is contributing to the sudden and dramatic decline in recorded incidence of bTb. In the first 3 months of this year there were 954 Tb incidents where cattle reacted to the skin test compared with 1,315 in the first quarter of 2005. A remarkable 27 percent drop.So far there have been 512 confirmed new TB cases [ ] In the first quarter of 2005, there were 802.The figures for January 2006 were broadly unchanged on January last year, indicating that the change happened suddenly in February / March. What makes the decline even more dramatic, is that 2000 more herds, and over 100,000 more animals, were tested in the first three months of 2006, than 2005."

Other reasons for the drop are listed in the article by various sections of the industry:

*Jan Rowe, the NFU TB spokesman highlighted Defra's 'zero tolerance' of overdue Tb tests which was introduced in Feb. 2005 as possibly giving an artificially high comparison figure.
*And Tb levels in badgers could be falling, or the tabular valuations introduced in February 2006 may be encouraging farmers to take the law into their own hands.
*NBA chief executive Robert Forster suggested a colder spring could be an influencing factor.
*BCVA president Andrew Biggs said that the 'knock on ' effect of zero tolerance could be contributory, but that the change to Dutch tuberculin "had to be a possible factor".
*Defra said that changes to the tuberculin was considered as a "possible factor", and analysis was underway to compare the performance of the Dutch Lelystad tuberculin, and the VLA home produced product.

The full text can be viewed at:

As we said in our comments section of the previous thread, many hypotheses may contribute. But that 'something' happened very suddenly, in February / March. Without wishing to dismiss any of the 'possibles' flagged up, we would point out that from Parliamentary questions, the residual effect of exposure to bTb in cattle is "up to 221 days in the UK strains".

So anything that happened to the badgers / cattle interface would have had to have occured, just as dramatically, last autumn and not in February this year. Which is why we suspect, Defra are "monitoring the effect of the tuberculin". By which of course, they may mean checking which batch numbers of Lelystad tuberculin went where. Not publicised is a county or regional breakdown of the figures in a format which allows comparison. Is one region affected by the drop more than another? We have heard figures of 40 percent bandied around for the SW, but Glos. do not seem to have had a similar reduction.

Of the 'zero tolerance' possibility mentioned by the NFU and the BCVA, comparison between Jan/Feb/March 2004 and its introduction in 2005, again using Defra figures which we had fortunately printed off and stored, produced no dramatic upturn. NHI's (New breakdowns) were 1093 in the first 3 months of 2004, compared with 1163 in 2005 - an increase of 50. Confirmed incidents recorded 587 in 2004, against 802 in 2005 and currently 512. Cattle slaughtered as Reactors to the skin test show a drop on 2004 of about 100; 5543 in 2004 and 5455 in 2006 (7731 in 2005) . So February / March 2006 is significantly down even when compared with Defra's 2004 figures.This should be excellent news. So why are we so jittery? And why are Defra (very belatedly) 'testing' the efficacy of Dutch tuberculin (used February / March?) when they have distributed it for almost a year with no apparent problems?
We reported the prelude to it's introduction in February 2005 in our posting;
A case of shutting the stable door?

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