Monday, 18 July 2011

Nantwich vet group wrong on ragwort

I have mentioned before that vets frequently get it wrong about Ragwort. This is a classic example from twitter today. Someone from the Nantwitch Vet Group has been tweeting poor information . Here are the tweets. It demonstrates how pervasive the misinformation about ragwort is.

TheEquineVets Nantwich Equine Vets
If you find Ragwort you MUST contact either the Landowner, Highways Agency or your Local Council.They are required by law to treat/remove it
Nantwich Equine Vets

Nantwich Equine Vets
TheEquineVets Nantwich Equine Vets
Some really great advice and information here about Ragwort - Please read this -

First of all they are wrong about the law. Landowners may be ordered to control certain plants including ragwort but they are not automatically required to do so.
This was the basis of several complaints to and consequent actions by the Advertising Standards Authority

The real problem is the website they are recommending. It is full of bad information. Firstly it,by implication, repeats the myth that ragwort seeds usually blow long distances. We know both from measurements and aerodynamics that they do not.
It repeats the legal myth. but worse it says this:

A horse can get ragwort poisoning without actually having any plants in their paddock! Seeds/spores from plants in neighboring fields can blow over and contaminate a paddock apparently free from plants. A horse can eat or inhale these - and cumulative poisoning can begin.

Let's start with simple biology. Flowering plants like ragwort have seeds but they do not have spores. It may be that they mean pollen grains but this hardly demonstrates proper knowledge of biology on the part of the webmaster. Improper knowledge on the part of a webmaster should warn against recommending a site.

I wrote about this before when this myth occurred somewhere else so I shall just basically repeat what I said then.

Firstly, whilst it is true that ragwort poisoning can be cumulative. The lethal dose is so high that it is often measured in percentages of body weight. The dose is minuscule!

Secondly, if you look at the biochemistry you can see the impossibility of this kind of poisoning. The toxins in ragwort are not actually poisonous in themselves. They have to undergo a conversion process. Some are destroyed in the digestive process. Some will be excreted unchanged. If they get through this then, and only then, they are converted into the breakdown products are they toxic and then those breakdown products are so reactive that they will react with almost anything in the cell. It is only those that reach the DNA in the cell nucleus that have a toxic effect and then if the damage is minor which it certainly would be, there are DNA repair mechanisms which would likely nullify any damage.

As ever good information on ragwort may be obtained from these sites.
Ragwort facts
Ragwort myths and facts
Ragwort the sense and the nonsense.
Ragwort Hysteria latest entries

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