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Wednesday 23rd May 2012

For a brief period, this morning, I thought I’d found a website dealing sensibly with Jacobaea vulgaris (syn. Senecio jacobaea), common ragwort, and its effect on horses. Sadly, it didn’t last.

It concerned an incident where a number of horses in the same stable became very ill after being fed hay contaminated with ragwort and, unlike nearly every other ‘horsey’ website, it pointed out that horses will not graze on living ragwort unless they are actually starving and that the problem comes when ragwort is cropped along with grass for hay.

Jacobaea vulgaris, common ragwort

I’ve said many times that horse owners, generally, blame the living plant for causing harm and my only explanation for this persistent disregard of the evidence and the science is that they want to absolve themselves for their own failures resulting from buying cheap forage and not taking enough care to find out how it has been produced.

In the incident I read about today, this focus on the living plant produced a problem I had not thought of before. The horses started to become ill after being fed to contaminated hay for four to six weeks and neither the yard owner nor the vet considered ragwort as a possible cause of the illness. Instead tests for worms and viruses were carried out and it was only once these proved negative and all other possibilities had been considered that ragwort poisoning was suspected.

Throughout all the testing the horses were still being fed the contaminated hay so what might only have been a serious problem became a fatal one with three young horses dying. Only after post mortem examinations on these three was the feed changed. It really strikes me as remarkable that it took all that time for the hay to be identified as the source of the problem. Perhaps the British Horse Society should focus on the issue of low quality feed as a risk to horses’ health rather than spreading lies about living ragwort.

Jacobaea vulgaris, common ragwort

I said I thought I’d found a sensible website but I should have realised sooner than I did that this was not so. What should have triggered by realisation was that the story was described as a case study.

Now, to me, ‘case study’ has a specific meaning. It refers to a scientific article published in a reputable journal giving details of a particular case. Such articles start by giving an introduction to the condition concerned or the poisoning agent and then provide detailed information on the symptoms, treatment and outcome of the case before making comparisons with previously reported cases. In other words, it is a thorough study providing reliable information.

When I relate some poisoning incident that I’ve read about or that has been told to me I call it a ‘story’ or an ‘anecdote’; I would never call it a ‘case study’. That’s why the alarm bells should have been ringing because purveyors of unscientific treatments of all sorts like to appropriate scientific language in the hope of giving false credibility to their stories.

Had I taken more note of the use of ‘case study’ early in the piece I should have been less disappointed to find that one of the other horses in the yard had been treated with aromatherapy.

Aromatherapy is one of the more curious of the ‘alternative’ techniques because no-one would deny the ability of a bad smell to make one feel ill and even induce gagging and vomiting. It would seem, therefore, that if a smell can make you sick a different smell should be able to make you well.

I re-wrote that last sentence because I originally wrote ‘feel sick’ and ‘feel better’ but realised there is an important difference. Such trials as have been undertaken have found that use of aromatherapy can produce a change of mood but does not produce any physical changes. In other words, trial subjects feel better but aren’t any different.

Like many such techniques, trials of aromatherapy often turn out to have tested something else. They report no effect from smelling the substance under trial but positive benefits if it is massaged into the skin.

Inhalation can, of course, have physical effects otherwise no-one would bother with Cannabis sativa, marijuana, and the use of Veratrum album, sneezewort, in sneezing powder wouldn’t have been outlawed in 1994 after it was found to cause damage to the nasal passages.

But the sort of inhalation offered by aromatherapists is not the same thing. This ‘case study’ showing how this horse recovered after being treated with aromatherapy is simply an example of the idea of post hoc ergo proptor hoc. Because the horse received aromatherapy the assumption is made that this is what produced the recovery.

In fact, the liver is much more resilient than was believed to be the case even quite recently so simply removing the source of the poisoning, the contaminated hay, would have enabled it to recover. It's just a pity that the yard owner, and even the vet it would seem, were not more familiar with the risk from ragwort contaminated hay.

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