Equine vet gets it wrong on ragwort.

 Today I am once again going to talk about my honest opinions on ragwort. It includes an example of a discussion where an equine vet got things wrong on ragwort. This happened on Facebook earlier in the week and I have given her enough time to respond so I think I should now share this encounter so that you can all see the problem.

As regular readers will know it isn't the first time there has been an issue with what an equine vet has said. I do wonder if they are taught all I would expect them to be taught. 

The issue in question here is whether you can diagnose ragwort poisoning with certainty. My view on this is, after having read the literature,  you cannot. It is quite simple really. There are characteristic symptoms of damage which can be observed under a microscope, but while those symptoms are characteristic of pyrrolizidine alkaloid poisoning caused by the toxins in ragwort, that is not their only cause. Another cause is damage by toxins produced in invisibly mouldy hay.

Since you have more than one cause it is surely not possible to say that the damage is caused by one of them.

Although it doesn't seem to be the problem in this specific case there is also the issue of vets doing blood tests which are just indicative of liver damage from any of a number of causes.  I got four letter insults from one equine charity which insisted that veterinary blood test results proved ragwort poisoning on twitter.

Naturally as a specialist on ragwort I do keep up on the latest scientific literature if I can and there is a paper published just last month that contains some interesting quotes.

"Outbreaks of hepatic disease are common and once often were suspected to be caused by pyrrolizidine alkaloid (PA) toxicosis,  although more recent evidence suggests that PA toxicity is far less common than generally suspected."

 Pyrrolizine alkaloid toxicosis is what happens in ragwort poisoning so the recent evidence suggests it is far less common than had been assumed. I've explained the exaggerations and nonsense statistics in previous postings.

 "We found that mycotoxins were present in >80% of hay samples fed to horses in the United Kingdom."

Now not all of them were the kind of mycotoxins that might be confused with ragwort poisoning on biopsy but we do know as I said above that this is assumed without biopsies.

"Interestingly, although not a specific finding, scattered individual hepatocyte necrosis and apoptosis are the most common histopathologic features in liver biopsy specimens collected from horses involved in outbreaks of liver disease in the United Kingdom." 

This is very significant because we can be sure what ever the cause that this shows that most cases are not ragwort poisoning, something which had been in print previously, but confirmed again here. 

Well, here is the conversation on Facebook. The quotes given are not the only source of information that I have to confirm this.  In case you're wondering my responses were in paragraphs. There is a way to do this on Facebook postings where normally pressing enter creates a posting, causing postings to be rather unclear.

Harriet Kate Fairhurst
Patrick Anthony Thirkell unfortunately, as an equine vet, I personally put to sleep 3 horses last year due to ragwort ingestion, causing irreversible damage to the liver. ingestion of ragwort causes Pyrrolizidine alkaloid toxicity, the alkaloids in toxic plants (such as ragwort) cause a primary toxic effect on liver parenchyma, leading to enlargement of liver cells, leading to impairment of cell division, resulting in large bits of the liver then being unable to function, ultimately leading to hepatic failure and death. There are many plants which cause it, however ragwort is the main perpetrator.

Bill Ellson
Harriet Kate Fairhurst How do you distinguish between liver failure caused by ragwort and liver failure caused by mycotoxins?

Harriet Kate Fairhurst
Bill Ellson ragwort poisoning specifically causes changes in liver cells termed megakaryocytes. On histology slides of a liver biopsy, these are very specific for ragwort poisoning.

Bill Ellson
Harriet Kate Fairhurst Really? Any peer reviewed science that supports that assertion

Neil Jones
Harriet Kate Fairhurst I honestly believe you are wrong.
First of all I think you'll find that megakaryocytes are bone cells responsible for
creating the platelets in blood.
I think you mean megalocytosis. Bill Ellson asked how you tell ragwort poisoning from poisoning by mycotoxins. Aflatoxins are mycotoxins and produce the same characteristic microscopic changes,
Indeed we know from the biochemistry why this happens and why they cannot be distinguished.
If more than one cause exists for an effect, then you cannot surely describe the effect as due to just one of those causes
A few excerpts from the literature:
"Hepatic megalocytosis can be observed in some aged animals, but is characteristic lesion observed in toxic insult by pyrrolizidine alkaloids and aflatoxins. " From Veterinary Toxicology Basic and Clinical Principles
"Hepatic megalocytosis is observed with certain toxic insults, particularly pyrrolizidine alkaloid toxicosis and aflatoxin toxicosis. " from Clinical Veterinary Toxicology.

 

 

 

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.

 

 

Redwings - Biologically ignorant ragwort nonsense

 I haven't blogged so much recently but this is such a good example for me to express my honest opinions on, that I'm no going to miss the chance.

Redwings is a horse charity and they have form for ragwort hysteria. Some years ago a leaflet they did was banned by the Advertising Standards Authority for scaring people with inaccurate scary information.

The latest piece of nonsense from them that I want to talk about here is this.

"The number of ragwort plants in the UK currently increases by a huge percentage each year. This is not surprising when you consider that each ragwort plant can produce between 4,760 and 150,000 seeds. Each seed has a 70% chance of germinating. The seeds can also survive dormant in the soil for up to 20 years."

Where do you start with this kind of nonsense!

There is no  evidence to support the notion that ragwort is increasing by a huge percentage The last available data shows a decline and equine charities at the time were claiming the same huge increases.

The justification is biologically ignorant rubbish! It does not matter how many seeds a plant produces or what the laboratory germination rate is as each plant produces on average just one offspring and creates the seeds necessary to do that. Surely anyone with any sense can see that? 

This germination rate is passed around to scare people. Stop for a moment and think, don't most plants germinate like that? I've just planted some alfalfa and clover in small pots, because I'll be wanting them as foodplant for caterpillars next year and will need to move them in and out of cages and to see the caterpillars clearly. I counted the seeds out and individually planted each one and they have all germinated. This is normal.

The earth weighs 5.972 × 10^24 kg that is nearly 6000000000000000000000000 kilograms. Let's assume that each ragwort plant produces 3332 offspring which is 70% of the lower figure they give for seed production to allow for the claimed germination rate. Put this into a calculator press the times key twice and keep pressing the equals key. After just seven generations the weight of ragwort plants exceeds the weight of the earth!

The argument being made is absurd, yet we know that some people will believe it adding more to the destruction of the environment unnecessarily.

And where do Redwings get their inspiration from. Well, regular readers will not be surprised to see them saying this:-

"Vet Derek Knottenbelt at Leverhulme Veterinary Hospital in Liverpool is a leading figure in the campaign to take ragwort and its devastating effects seriously. He is at the forefront of research into developing a reliable test to link liver damage specifically to ragwort toxins, which at the moment is impossible to distinguish from other causes of liver disease in the living animal. If you ever have the chance to see Derek Knottenbelt speak on the subject, don't miss it! "

Oh dear, oh dear, him again!  For new readers, this is the man who claimed ragwort was a serious problem in South Africa, where in fact it has never been recorded. He also claimed it was increasing when it was decreasing and also that it is responsibly for the decline in the cinnabar moth, because it was poisoning it! Bonkers or what! It is the natural food plant of the moth!!!

We have a good idea of what he says in his talks because of an article he wrote and here is my debunk of of what he said. I identify 17 issues of scientific problems with the article! It is rubbish from beginning to end!

He is retired by the way and the test was the subject of a PhD thesis by a student. It essentially didn't show anything our of 91 horses with liver problems suspected to be ragwort, only 1, an obvious abuse case showed positive results. The test has never been rolled out. It wasn't viable. Yet of course Redwings use it to make this man look good.

They are of course in violation of Charity Commission rules once again!

 

 

Bracknell Forest Council's ragwort misinformation harms conservation.

 I can't tweet all of this so once again I'm using the blog as an addition to social media. 

Conservationists are unhappy with them. I'll use a couple of analogies. Imagine they said Climate Change was a hoax. Climate campaigners wouldn't be happy. Imagine if they said the Covid pandemic was a hoax, the medical profession would be condemning them. Well, this blog is an expert in an area of science also telling them not to spread nonsensical myths.

Bracknell Forest Council have put a piece on line with myths about ragwort.

The first thing to remember that Bracknell Forest Council has a legal responsibility to promote biodiversity under the Natural Environment and Rural Communities Act 2006.

The second thing to say is that they have no general legal responsibilities to control ragwort CONTRARY to what they are saying.

The third thing is that it isn't about the cinnabar moth. It is about all the other widlife affected.

"They don't seem to be very well informed because they say:-

“While ragwort has some biodiversity benefits, there are many other wildflowers in our meadows, that provide food for insects."

Imagine an art gallery saying we can burn our Van Gogh because we have a lot of other paintings, this is rather analogous. Ragwort is one of the most ecologically important wildflowers, yes there are circumstances where it needs controling but  they are damaging the environment by spreading myths about it.

This is what Friends of the Earth say about it in their briefing on the subject (Yes a major environmental organisation has a briefing on it. which exposes just some of the hystercal myths.)

 Ragwort (was Senecio jacobaea now Jacobaea vulgaris) is an important wildflower for invertebrate wildlife:

- 35 insect species totally rely on Common ragwort for food including 7 moth and 7 beetle species;

- Another 83 species are recorded as using Common ragwort often as a significant food source, with a further estimated 50 species of parasite in turn feeding on those;

- In addition to these 133 species, Common ragwort is a significant source of nectar for others including bee species that specialise in feeding on yellow Asteraceae (daisies) and many species of butterfly.1

- Government research shows that of over 7,000 plant species in Britain Common ragwort is the 7thmost important nectar-producing plant.

Now they are  breaching their NERC Act duty by spreading falsehoods about this ecologically important art of our natural heritage.

The first thing they get wrong is a matter of liguistic and environmental literacy.

They say:-

"Ragwort is classed as a harmful, or injurious weed under the Weeds Act 1959. This is because the plant can be poisonous to certain animals if eaten."

No this is not true. The word injurious doesn't mean it will poison something. The 1959 act wasn't debated in Parliament but as a Consolidation Act it repeated stuff originally pased in 1920. It is clear from Hansard at the time that the meaning is injurious to land not to animals. There are other plants listed, also ecologically valuable, and these are all listed in Richard Mabey's famous book Food for Free. You can eat them!

Then while talking about the law they say:-

"The occupier of land is responsible for clearing harmful weeds, such as ragwort, where they might spread onto land used for grazing livestock or growing crops.""

Regular readers will be hearing a claxon in their heads at this for this is like climate or Covid denial. It is a nonsensical falsehood.

This is all the law says that makes anyone do anything.

"Where the Minister of Agriculture, Fisheries and Food (in this Act referred to as “the Minister”) is satisfied that there are injurious weeds to which this Act applies growing upon any land he may serve upon the occupier of the land a notice in writing requiring him, within the time specified in the notice, to take such action as may be necessary to prevent the weeds from spreading."

So to be clear. You may be ordered to control the plant but in the absence of the law there is no need to do anything. There is no responsibility at all placed on anyeone by the law to control these plants where they might spread. None whatsoever!

Then they go on with this scary stuff as if ragwort is some kind of triffid.

"We dispose of the waste responsibly, to ensure there’s no risk of spread by seed dispersal. Each plant can produce thousands of seeds, which are dispersed by wind. The seeds can remain dormant in the soil for several years."

This makes it sound really dangerous now there are . as a result of the hysteria, rules about disposing ragwort, but it is really unethical for ecologists to make a big deal out of them, because it should be obvious to anyone who understands the plant that they are based on hysteria.

Guess how far the best study says seeds travel from the parent plant?  It says that hardly any seeds travel more than 40 yards! 

There is a simple bit of science that I would hope is still in GCSE physics.  You can tell how far away the seeds would fall in general like this.  Work out how long it takes a seed to fall to the ground and then work out how far a wind would blow the seed sideways in that time. It is a classical example of plotting motion separate the vertical and horizontal components and calculate. Do this and you'll find seeds don't usually move far. Having said that there are going to be exceptional events but given the plant is a native these not particularly significant. 

This isn't big complicated science. It the stuff children do in exams at 16!

.Also there is the basic ecology! Why mention thousands of seeds? This is normal for so many plants and on average only one plant will grow from all of them. It it were not so than we'd quickly be buried under the weight of plants. It does however make the plant look scary.

They have been distributing frightening and false information which undermines conservation on-line to maybe thousands of people. This is not acceptable!

To twitter. This site is being blocked.

( Note I was first made aware of this by flag waving, seemingy far right bigotted ragwort basher. So I suspected they were involved. It transpired subsequently that there was a general problem effecting other blogs too.)

 Dear Twitter, I am just about to report to you that this site is being blocked on twitter.  I cannot tweet links to it. There has been a hysterical campaign against the plant ragwort, which is the subject of a campaign of misinformation. It annoys some libelous cranks that I debunk this stuff on this blog. They have probably reported me. look at my previous entries. I could probably name the accounts doing it. Perhaps they should be suspended for misuse?

If you have any doubts about me look at the number of academics who follow me @ragwortfacts on twitter or ask Matt Shardlow CEO of the Environmental Organisation Buglife.

Here is a sample.

Paul R. Ehrlich is particularly notable as a world-famous professor.