Scientific Chinese Whispers over Ragwort

 All the time I see assumptions made about ragwort that my detailed study over the years shows to be wrong. People say things based on their prejudices that they assume to be true and I know they are not.

Frequently ragwort haters will say I lack authority in some way or other. You must go to peer reviewed papers, even when actually that research shows I am right. The authoritarian mind has been shown to be poor at thinking and there's good research behind that.  Thinking that authority is  the best source is also one of the biggest errors you can make in science. As  Nobel Prize winning physicist Professor Richard Feynman summed it all up in a famous quote made during one of his lectures, which was recorded on film for posterity.

"If it disagrees with experiment, it is wrong. In that simple statement is the key to science. It doesn't matter how beautiful the guess is. It doesn't matter how smart you are. Who made the guess . What his name is. If it disagrees with experiment, it is wrong. That is all there is to it."

He was talking about the derivation of knowledge about the laws of physics but the principle applies to all of science.  Experiment or evidence is the key not who said something or where it was written etc. I have here a classic example of why peer review does not necessarily assure validity.

Doing my research I came across a statement in a peer reviewed paper illustrating exactly why evidence is preferred over authority. It was saying something I had read a vet saying, that seedlings are eaten by animals and cause poisoning. Now I know, from detailed reading of the literature that small doses do not matter so this is not likely to be true and without evidence it shouldn't be accepted. There is even a published experiment where animals were fed lower doses of the type of toxins that are in ragwort and suffered no damage where as higher doses did cause damage. This is exactly what the biochemistry predicts.

As for challenging vets when I am not one. Again this is a matter of evidence not authority. I would guess that I know a lot more than the average vet does about this specialised subject area. I've seen what the textbooks do and don't say and as we know I regularly criticise a veterinary professor for talking nonsense, with really good evidence. I may have more to blog about this issue of vets getting things wrong in the near future.

Now what is a seedling? Well in my mind, as a native speaker of English, a seedling is something an inch or two high,  a new plant that has just begun growing from a seed. It is perhaps a lack of proper appreciation of that meaning that caused this particular myth to start. For as you'll see the origin of this myth has nothing to do with anything that could reasonably be called a seedling.

The first paper in the chain is this Epidemiology of intoxication of domestic animals by plants in Europe by Cristina Cortinovis, Francesca Caloni .which says:-

"Poisoning generally occurs when seedlings are grazed accidentally along with other forage or when there is a lack of other feed (Vandenbroucke et al., 2010)"

So the next thing is to follow that reference and it leads to Animal poisonings in Belgium: a review of the past decade by V. Vandenbroucke et al.

This says something rather different it talks about a lack of other feed, and isn't the primary source.

"Although herbivores seldom eat mature plants, poisoning can still occur when seedlings are grazed accidentally along with other forage or when there
is a lack of other feed (Polhmann et al., 2005)"

So this leads us on to what is the final source. It does not provide evidence just what is really the opinion of the author, but also a rather weird definition of seedling.

"Fortunately, herbivores seldom eat mature plants (Fig. 1), but poisoning can occur when seedlings (Fig. 2) are grazed accidentally along with other forage or when there is a lack of other feed." 

But just look at the pictures in the figures. They are below. These aren't seedlings but half-grown plants at the end of the first of their two years of life!  Through being repeated a false assumption has become stated as fact, as it appears a paper's author didn't check the primary source for validity. I have seen a video of a horse deliberately avoiding a plant like that.