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Tuesday 17th July 2012

I have to make a correction to what I wrote last Thursday. Actually, I think I need to make two corrections but I’ll come back to the second one.

After tweeting about my blog entry saying there was no Ragwort Awareness Week (RAW) this year, I received a tweet from the British Horse Society (BHS) saying that RAW is 23-29th July this year. At about the same time, my Google Alert for ‘ragwort’ took me to a couple of websites that had, clearly, received a press release from the BHS about RAW accompanied by some figures from the 2011 survey aimed at determining the extent of Jacobaea vulgaris (syn. Senecio jacobaea), common ragwort.

So, I was wrong to say there was no RAW and, frankly, I don’t like being wrong. I thought I’d better try and understand what led me to this error. It didn’t take long to find. The BHS webpage announcing the 2011 RAW is still online and it says;

‘While the results of this survey are important (see below), it’s not enough. By carrying out the survey in the same week annually (emphasis added), we are hoping to gain an insight into trends in ragwort proliferation and to strengthen the argument to control it.’

Since both RAW 2010 and 2011 began on the 2nd Monday in July, I took that paragraph at its word and concluded that RAW not having been announced by 9th July there would be no RAW 2012.

I sent a tweet to the BHS asking why the dates had been changed given that this meant that the trends it said were of such importance could not be monitored but, at the time of writing, I haven’t had a reply.

The second correction I referred to at the start comes because, last week, I wrote;

‘…the society seems to be taking a more sensible and pragmatic approach to the issue of Jacobaea vulgaris (syn. Senecio jacobaea), common ragwort.’

From the two pieces my Google Alert pointed out¹, I have realised that this statement was not correct. The BHS has placed its press release on its website and it makes for very discouraging reading. The second paragraph says;

'Every year, animals die painful and unnecessary deaths as a result of damage to their liver from consuming Ragwort.'

The expectation is that you will accept that as fact because no figures are given to support it.

There's been a change when it comes to giving the intention of the surveys. The BHS now says;

'By carrying out the survey annually, the BHS is hoping to gain an insight into trends in ragwort proliferation'

whilst ignoring the fact that the change of date makes it impossible to reliably demonstrate a trend.

I should also mention that I'm unhappy with the use of the word 'proliferation'. That says the BHS has decided ragwort is spreading never mind what the evidence suggests. In effect, the BHS position is that it wants to make people believe ragwort is becoming more prevalent and it is encouraging people to contribute information only in support of that position.

The 2011 survey found that 20,781 horses were reported ‘grazing either on, or within 50 metres of, fields containing ragwort’.1 The 2010 survey found the number to be 13,189. That implies an increase of 58% in the number of animals ‘at risk’ from ragwort.

Where shall I start?

When trying to understand the World Drugs Report for 2012, I wrote about people overstating the accuracy of their data. There is absolutely no way that the BHS surveys are accurate to one single horse. Even if the reporting were reliable, (I’ll come to that) the chances of errors in counting horses in a field are such that ten different people would likely arrive at ten different totals. Quoting the figures to the nearest horse suggests that either the BHS doesn’t have anyone with any understanding of maths or it doesn’t care whether its information is accurate or not.

Let’s go back to whether the reporting is, in any event, reliable. I’ve written about this before but just to repeat, this is a self-report survey with no attempt to check whether people completing it have any competence to identify common ragwort (the only species of ragwort controlled by the Weeds Act 1959). There is no obligation to provide identifying details and no attempt to prevent one person making multiple submissions. I know this because I've completed it three or four times. The survey is still open for completion so this cannot be the “snapshot survey” that it is being reported to be.

The BHS doesn’t say how many submissions it received for either survey. You would expect word to spread about any event and, therefore, it is likely that more people were aware of the survey in 2011 than in 2010. If, say, twice as many people completed the survey then that apparent 58% increase in the number of animals exposed actually becomes a decrease in exposure.

Then there is the matter of outcomes. To get an understanding of what this alleged exposure to Jacobaea vulgaris meant you would need to have figures for the number of horses diagnosed as suffering from liver disease. This is the classic Jerry Maguire test situation. Where are all the diseased or dead horses? The BHS, in fact, shoots itself in the foot if its claimed 58% increase in exposure to ragwort does not produce any increase in the number of animals becoming ill.

Still nothing from the BHS about the date change so I can only guess that it has something to do with having RAW in the English school holidays when more people are likely to be out in the countryside and there may be more responses to this year’s survey. It remains to be seen, of course, whether the survey is any better constructed this year.

What we have then are the unscientific results of the BHS surveys being used to press a campaign against a native plant rather than focus on the responsibilities of horse-owners to provide safe food for their animals.

The BHS release quotes Lee Hackett, BHS Senior Executive (Welfare), as saying;

'Our surveys so far have been a great success and produced some fascinating results that we can use in our lobbying to get some action taken. But we need far more data to help us get a handle on the true prevalence of ragwort, two years is not enough.'

Let me be completely clear about this; the surveys undertaken by the BHS will NEVER 'get a handle on the true prevalence of ragwort' and, even if they did, the prevalence is not important. It is the harm that matters and the BHS should spend its time discovering the true extent of disease from ragwort.

The most recent accounts for the BHS show that it had a surplus of income over expenditure of £0.7m and reserves of £8.9m so it is a well-financed organisation.

My question to the BHS is, therefore, if it is convinced that common ragwort is causing such a problem, why does it not use some of its substantial reserves to undertake a proper, rigorous study of the effects of pyrrolizidine alkaloids (PAs) and then, if substantial effects are proved, finance a further study to identify the source of those PAs be it living Jacobaea vulgaris, conserved forage that has not been properly produced or any of the many other plants that contain PAs?  

References

^1.Make getting rid of ragwort a priority says horse charity Smallholder 16th July 2012