Grey horses are full of cancer when they turn white

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An older and (supposedly) wise horseman told this to me recently.


He said "Once a grey turns white they are worthless and almost always full of cancer"



This sounds like a load of poppycock to me
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Anyone else ever heard of such a thing?

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Oh dear
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looks like my 24 year old GREY share horse should be very much dead then....ill let his owner know that her horse has cancer.....
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i dont really know about grey horse turning white having cancer, but i agree that they are more prone to melinomas!
but you will never get a white foal, as a horse that gets "the lethal white gene" will die before birth.
 
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i dont really know about grey horse turning white having cancer, but i agree that they are more prone to melinomas!
but you will never get a white foal, as a horse that gets "the lethal white gene" will die before birth.

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Well, you could get a few spot appy or a cremello that would look white, before you panic everyone who may ever see a white foal, lol!! And a lethal white dies after birth, not before, but that's *usually* only a concern to the overo breeders.

But that's kinda off topic - as you said, it's the grey horses that are more disposed to melanomas.
 
My 16 year old grey has a couple of black lumps on him, should I be concerned now? He has had them since he was about 12 and they have not grown, bled or anything, they have just sat there and I hope they continue to do so without causing any problems.

Another sleepness night for me!!
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No, if they're not causing a problem, usualy best to leave them. As said, many horses have melanomas without them causing a problem, it's only if you're unlucky that they'll turn nasty.
 


[/ QUOTE ] I still am not buying his theory that horses can remain healthy surviving off of eating snow in the winter instead of having fresh water [ QUOTE ]

Well wild horse survive long freezes, as long as they can fins somethignto eat, when all ponds and streams are frozen

Ifyou eat a hanful of snow,it melts and becomes water in your mouth- An Ice lolly or ice cream is water or milk by the time it reaches your digestive system.
 
I understand it in theory but not practical keeping methods for domesticated horses
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I would rather keep my horse adequately hydrated than barely hydrated just enough to stay alive.
Wild animals do not always live the longest lives either and our domesticated versions can often be less resilient.



Snow will melt eventually into water but it takes your core temperature down sometimes in doing so. The very same reason they tell people lost in blizzards to be careful eating snow to stay alive. A horse will drink far more water if it is kept under freezing temps and drinking more is good for them.
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There are one or two inaccuracies on this thread, which I may be able to help with (I work in Cancer Research and have done for 9 years, before which I was working in diagnostics and before that was studying it).

Greys are not full of cancer. Greys are prone to melanomas; this is due to genetic mutations. There are 31 genes associated with pigmentation disorders, called 'congenital pigmentation syndromes'. One such gene, key to premature greying, is that which produces Mitf, or Micropthalmia Transcription Factor. There is a critical level of Mitf required for survival and differentiation of melanoblasts (the precursor to melanocyte cells, which produce melanin). In greys, they are born with pigment, but where there is a Mitf deficiency, the melanocytes die off and are not replaced, which is why they grey out so incredibly fast - juveniles of course produce skin cells at a much faster rate, as they are growing and when they shed their baby coat - bam! White horsey! I don't remember what affects the rate of this transformation, but I do know that Mitf comes in 5 types, or isoforms as we call them! It's not my area, so I can't expand on that!

Mitf is central to a whole load of other factors which are present in various oncogenic (cancer causing) pathways, so any additional mutations which affect those factors will predispose a grey to melanoma. That DOES NOT mean that every grey will develop melanoma and even if they do, the combination of mutations in different genes will influence whether these melanomas are malignant (definition of malignant is being invasive, aggressive/rapid growth or spreading (metastisizing) to other parts of the body). So don't go writing off all your grey horses!

The basic definition of cancer as I learnt it all those years ago is 'uncontrolled growth'. What the body does in response to that uncontrolled growth determines what happens next and if the cancer becomes malignant. A wart, for example, biologically speaking, is a cancer, as is a cyst, or mole (melanocytic naevus).

I need a swim, now!
 
Thank you,what a brilliant reply
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So, in answer to the question about the old wives tale about "all greys get cancer" the answer is no.

and, if I grasp your reply correctly, that genes play an enormous part on whether a cell develops into a cancer, and therefore not all greys have cancer. ( I hope that's right, forgive me if I'm wrong
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It's just that I feel quite strongly about some of these old sayings, and I do believe they make people biased about animals which would otherwise do a perfect job for them. It's probably the generalisation I object to, and not the, granted, common knowledge thoughts behind them.
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Thank you for that very comprehensive reply
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This forum is great for finding out lots of interesting facts
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Interesting reading Frasurrey thanks.

Not all grey horses have 'cancer' but it is an extremely rare grey horse that doesn't have melenona's by the time it's middle aged. Some are external and you can therefore see them, but many possibley most) are internal. It's only on post mortum that they're found. I've seen plenty of grey horses with hundred and hundreds of little black lumps on their intestinal mesentry.

They're rarely of any consequence unless they become malignant, or they physically cause problems (by their position)
 
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and, if I grasp your reply correctly, that genes play an enormous part on whether a cell develops into a cancer, and therefore not all greys have cancer. ( I hope that's right, forgive me if I'm wrong)


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Cancer is a genetic disease, so yes, genes (or a mixture thereof) play a huge role.
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Some of these old sayings do have some truth - behaviour, for example is linked to coat colour through 'gene linkage', but again, the products of genes interact with each other on a far grander scale than we understand at present. No pathway in any cell is exclusive-they criss-cross and affect each other.
 
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