Does anyone know yet why sycamore seeds are suddenly so toxic?

[Patchworkpony]

Does anyone know yet why sycamore seeds are suddenly so toxic? Having kept horses and ponies for decades, with sycamores around, I had never heard of the problem until recently. Because we were showing at top level years ago so knew heaps of people, who all liked to talk about their own equines, I'm quite sure if any had died suddenly with no apparent cause we would have heard about it. This problem does appear to be relatively new and if it is - why? There is a real sense of panic now if horses are kept within range of these wretched trees and frankly I don't think owners know what to do for the best. Have there been any deaths reported this autumn yet?

 

[ozpoz]

Like you, I wondered about this when I first heard of it. I wonder if the illness was diagnosed as grass sickness in the past?

 

[epeters91]

I had a horse with atypical myopathy about 4 years ago (now known to be caused by sycamore seeds) not sure why they are suddenly so toxic but I can say it was a horrible experience. I was very lucky in that I caught it early and my gelding lived but a livery yard nearby lost one of their ponies to it. Maybe some horses are more susceptable to it than others? At the time the vets still didn't know what caused it and my boy was the first horse to have survived it in our area for a 20 years (or so the vet said!) he'd been in the same field for 3 or 4 years when he was affected. We had seperated the field with electric fencing and he was in the section near sycamores so I now make sure no horses graze there during autumn and spring when the sycamore seeds are about.

 

[Toby_Zaphod]

I don't think it's that they're suddenly toxic, people are just more aware of what is & isn't good for horses. Over the years we've had horses & there have been Sycamore & oak in the various paddocks. There were probably other plants, shrubs & trees there as well that weren't great for horses that we weren't aware of. I think if you worry too much about these potential issues you will probably never find a paddock that it is 'safe' to turn out in & you become paranoid. If you think a particular tree/plant is an issue either move your horse, fence off the tree or cut it down.

 

[Meowy Catkin]

Some, but not all seeds contain the toxin hypoglycin-A.

From what I have read, it seems that the toxin can be washed from the seeds into the ground and onto the grass in very wet weather. Once the seedlings get old enough to have proper sycamore shaped leaves growing, they are less toxic and eventually cease being toxic as they continue growing.

It is thought that many cases of AM were misdiagnosed as colic in the past.

 

[southerncomfort]

One theory is the changing way we keep horses. Because they aren't worked as they would have done in previous decades/centuries we are having to heavily restrict grazing and in some cases horses are kept on pretty bare to non existent grazing. The seeds have always been there but only now are horses starting to eat them due to restricted grass.

My feeling is that it is a combination of many factors that has led to the sudden increase in cases of atypical myopathy.

 

[Meowy Catkin]

They are diagnosed by blood test now. How long has that been available? Before the blood test it would be easy to misdiagnose.

 

[applecart14]

I think its to do with the flucuating weather changes. My sympathies go out to all those affected by this dreadful disease.

 

[Goldenstar]

My vet feels that warmer winters may have a role .

 

[FfionWinnie]

Think it's more likely to be awareness rather than a change in the seeds. Lots of colic is actually EGS and the same could be said for AM.

 

[JillA]

Some, but not all seeds contain the toxin hypoglycin-A.

From what I have read, it seems that the toxin can be washed from the seeds into the ground and onto the grass in very wet weather. Once the seedlings get old enough to have proper sycamore shaped leaves growing, they are less toxic and eventually cease being toxic as they continue growing.

That confirms what someone told me recently - not all seeds, not all trees and not all locations cause problems. It really is a lottery but I do think restricted grazing can contribute to them eating more stuff they shouldn't.

 

[Patchworkpony]

One theory is the changing way we keep horses. Because they aren't worked as they would have done in previous decades/centuries we are having to heavily restrict grazing and in some cases horses are kept on pretty bare to non existent grazing. The seeds have always been there but only now are horses starting to eat them due to restricted grass.

My feeling is that it is a combination of many factors that has led to the sudden increase in cases of atypical myopathy.

I totally agree as so many horses no longer do a 'proper' job but are kept out for a large part of their lives and are therefore more likely to eat the seeds and seedlings.

 

[Alliya]

I lost my youngster 4 years ago the vets where still trying to find out then what was the course then it had been a wet horrible October we had never heard of it before then but i was not the only person to lose a horse that winter locally i know of another 4 who also where PTS with in a 2 mile area of mine that winter

 

[fatpiggy]

It is indeed all very strange. Sometimes it seems that Grass Sickness and AM are interchangeable so I am sure cases of one have been diagnosed as the other, and acute colic misdiagnosed too. I kept my horse in an area with a few nearby GS cases within the last 20 years and the field was surrounded by sycamores. My horse actually used to go out of her way to eat the leaves either after they had gone brown and fallen off or when they were very dark green, just before the colour change. She wasn't the remotest bit interested in them at any other time of the year. The only trees we ever worried about were oaks because of the acorns. There were horses and ponies of all ages on that land, and it varied from long to overgrazed. No cases of AM at all.

 

[Horsewithsocks]

I have kept horses for ages in a paddock with a big sycamore tree. My feeling is that, maybe due to global warming, the trees seem to produce many more seeds now. The one at the top of my paddock was covered with them. I have fenced off an picked up as many as possible.

 

[Patchworkpony]

I lost my youngster 4 years ago the vets where still trying to find out then what was the course then it had been a wet horrible October we had never heard of it before then but i was not the only person to lose a horse that winter locally i know of another 4 who also where PTS with in a 2 mile area of mine that winter

So sad - I feel really sorry for people in this situation.

 

[Patchworkpony]

I have kept horses for ages in a paddock with a big sycamore tree. My feeling is that, maybe due to global warming, the trees seem to produce many more seeds now. The one at the top of my paddock was covered with them. I have fenced off an picked up as many as possible.

It could well be global warming - I swear the horseflies are bigger!

 

[Beausmate]

What happens to the seeds in the winter? People say spring and autumn are risk times, they're growing in the summer but what are they doing in the winter? They're still on the ground and I would have thought most likely to be eaten over the winter months, or do they not because most people either keep in or feed hay?

I have what I believe to be a sycamore in the field, I don't allow the horses to graze too close to the ground in the area with the most seeds (they carry a long way down the field, but fairly concentrated) and they don't seem remotely interested in them, but without watching them, I don't know for sure.

I wonder if the age of the tree has anything to do with the level of toxin?

Hypoglycin -A is also found in the seeds of unripe ackee fruit.

 

[Sukistokes2]

It is prob more to do with the fact that people are more aware and talk more on places like this, that means people are more clued up. I do not think the seeds are more toxic I just think we now know there are consequences which, before may have been written off as colic. My friend never uses computers, doesn't read up on new illnesses but when , I mentioned it to her she just shrugged and said "everyone knows that you shouldn't graze around sycamores like it was old news, maybe it was. Having had horses for 40 years it has really changed the way we keep them. Much smaller paddocks, restricted diets, if your horse got fat in the old days you just rode it more.

 

[Patchworkpony]

if your horse got fat in the old days you just rode it more.

Ain't that the truth!!

 

[MontyandZoom]

I'm sure that there were a few early cases that were misdiagnosed as colic but on the whole the symptoms are quite different from a veterinary point of view. The muscle breakdown causes myoglobinuria which results in urine that is the colour of coke which is the telltale sign.

There is plenty of research that is being done into why the hypoglycin A is now so concentrated in certain seeds but my feeling is it will be the 'new grass sickness' in terms of never really understanding what the particular circumstances are that cause the clinical disease. It is a hideous disease As a vet, grass sickness and atypical myopathy top the list of cases that make me need wine when I get home from work!!

 

[ycbm]

My understanding is that hypoglycin A is in some seeds and not others on the same tree, likewise in some parts of the same tree and not others.

If that is correct, then that smacks to me of an infection, which the tree partly controls. And an infection might explain why this is seemingly 'new' disease, as it spreads from one tree to another,

Does anyone know if infection of the tree as a cause is being considered, or maybe already written off as a cause?

 

[Gift Horse]

My understanding is that hypoglycin A is in some seeds and not others on the same tree, likewise in some parts of the same tree and not others.

If that is correct, then that smacks to me of an infection, which the tree partly controls. And an infection might explain why this is seemingly 'new' disease, as it spreads from one tree to another,

Does anyone know if infection of the tree as a cause is being considered, or maybe already written off as a cause?

I have wondered about this with so many sick trees - Ash die back etc. Maybe something is affecting the Sycamores making them toxic.

 

[MontyandZoom]

As it happens my other half is a botanist and this is something we have discussed a lot. So far the research isn't pointing that way - more towards environmental factors increasing the concentration of the toxin

 

[Patchworkpony]

As it happens my other half is a botanist and this is something we have discussed a lot. So far the research isn't pointing that way - more towards environmental factors increasing the concentration of the toxin

Interesting - what sort of environmental factors?

 

[fatpiggy]

Ain't that the truth!!

Yes and we fed them much more appropriately back then too. Like our diets now, everything is processed and sugary. When I was a kid it was hay and grass (straw for fatties) and they only got a scoop of oats through the summer when it was show and gymkhana season. We rode to shows, an hour or more away, did 6 or 8 classes and then rode home again. I'm absolutely certain that we rode longer back then too, although we didn't hammer them and respected them as working animals. Too many people today seem to treat them like machines and know little about fitness and workload.

 

[EmmasMummy]

We have sycammores in my parents garden, and we kept a number of horses there for years with no issue, then suddently neighbours pony who was using our field dropped dead about 5 years ago. I did wonder if it was toxin related. Then last year the other one died. Neither were very old really. It jsut seems too much of a coincidence now.

 

[Prince33Sp4rkle]

One theory is the changing way we keep horses. Because they aren't worked as they would have done in previous decades/centuries we are having to heavily restrict grazing and in some cases horses are kept on pretty bare to non existent grazing. The seeds have always been there but only now are horses starting to eat them due to restricted grass.

My feeling is that it is a combination of many factors that has led to the sudden increase in cases of atypical myopathy.

i suspect(personally) that this is a big factor.

livery yards over graze fields to the point of zero grass, and many people have ponies and cobbier breeds that only have to sniff food to expand and get worked once or twice a week...... Hungry and bored horses look for alternative forage

i had a juvenile sycamore removed last year. It had been there for 16 years,growing slowly from a seedling its self and never caused a problem, but the horse in that particular field was always a poor doer with a lot of lush grass. Now the horse in there is a fatty,and needs less grass, so the paddock ends up more closely grazed all over, and the sudden influx of seedlings was too tempting to ignore, so down came the tree.

 

[milliepops]

As it happens my other half is a botanist and this is something we have discussed a lot. So far the research isn't pointing that way - more towards environmental factors increasing the concentration of the toxin

interesting
On a side note, nice to see you posting again M&Z, I used to like hearing about little Zoomy

 

[SO1]

I think the lack of grass is a bit of a red herring as on my last yard a horse died of sycamore poisoning and there was loads of grass in the field as it was a field that had been rested for quite a few months. The seeds can get everywhere and even in the long grass they can still get consumed. It is a bit like Russian roulette you don't know which seeds are going to be poisonous.

I am not convinced it is environmental as otherwise all the seeds on the tree would become poisoned as they were subjected to the same environmental conditions. I wonder if is a disease or parasite or fungus which just gets into some of the seeds. An interesting PhD project perhaps for a botanist, if they could get funding.