Greys staying dark longer: genetic or environmental?

[Goo]

[QUOTE=ponygirl;5054561]
I call it the cow skull look.[/QUOTE]

Or the “elderly Labrador look,” as I once heard someone say. Made me chuckle, because how many of us haven’t known elderly, silver-faced Labs?

It does seem to make sense that there would be correlation between melanomas and rapid/early graying. I had two horses who were both white very young. One was a crippled (pasture sound only) OTTB that my family rescued when I was a teenager. He was a rack of bones and we nursed him back to optimal weight. Got him at 6 and he was already completely white, with a number of melanomas under his tail. After a period of time, he was no longer able to be kept pasture sound and was euthanized at 7. Had he lived longer, I suspect his melanomas would have been aggressive.

The second was also a TB, purchased around 7 or 8. He was already pretty light (fleabitten gray, with a bit of pepper in his mane being the only remaining gray), and also had quite a few melanomas under his tail. They were aggressive throughout his life - had to be retired by age 13-14 (despite being totally sound), due to numerous melanomas growing under the skin in his mouth and along his lips, rendering him unable to wear a bit. He was way too hot to ride in a hackamore (and I was only a kid at the time), so there was nothing to be done. He also had a large golf ball sized mass under the skin on his left cheek, many in his sheath, and the mass under his tail was about softball size. By the time he was sent to a friend’s retirement farm at 18, the mass under his tail was very large cantaloupe size and constantly ulcerating. I wanted to put him down at that time due to the ulceration, but he was full of life and never noticed it, so others talked me out of it. He was a great companion for my friend’s horses and full of piss and vinegar (one day jumping out over the pasture fence and running back to the barn squealing the whole way, when they dared bring the other horses in first before him), up to his death around age 20. He was fine, then had a sudden bout of colic late afternoon/early evening. By the time the vet made it out in the late evening, he was ready to go. As soon as she arrived and saw him, she knew it was impaction caused by large internal melanomas. Euthanized him and did a rectal after, which confirmed it.

I do think these two becoming white at a young age was a factor with their aggressive melanomas, but TWO is hardly a conclusive sample. And to add to my previous post, I have to wonder if there might be some genetic resistance in the PRE breed overall, because with the earlier-graying (although not SUPER early) PREs in Spain, I have seen quite a few that were completely white but did not have any visible bulges under their tails. Seemed to be far fewer white-gray individuals with any visible melanomas, as opposed to the grays I have seen in other breeds. But again… hardly a conclusive sample!

[Kerole]

I have had a few greys over the years. At one time I had 2 grey broodies - one flea bitten with black legs at 20 and the other pure white at 7.

The flea bitten mare had 9 foals - none grey.
The white mare had 9 foals - one grey. He was born black and was still near black aged 5. Just a few white bits began to creep into his face and a few dapples were showing by aged 9. But he had a pure white chunk of tail from the bottom of the dock that came through when he was 2!

A series of 4 siblings (3 full and 1 half) from the same grey mare. They were all from grey sires. The 3 full sibs were born brown went a grubby roanish grey at 2 and slowly greyed out from there. The half sib had a different grey sire. She is chestnut.

[camohn]

From my obsevations…genetic. My mare is getting noticeably gray now at 8, which is pretty slow…and I know a number of foals from her (gray) sire have also been slow to gray out.

[DandyMatiz]

[QUOTE=columbus;5055496]
I have a likely homozygous mare who was totally white by 5 and her heterozygous chestnut born daughter who is the black dappled body black mane variety and is faded but still pretty dark at 5, I have seen a couple of her sisters on the sires side and they have the same greying pattern though he is a red chestnut, the 4 yo heterozygous brother also born chestnut by a different sire is greying faster without as much dappling and still has orange casts to his mane and tail. I think especially in the olden days that the horses in a region were similarly bred, similar genes, so you saw similar greying patterns and now you are in a small restricted region and have the same influence by a relatively small number of genes. They will share a greying pattern. In Minnesota the Arab stallion Ferzon had a huge influence and he was a grey horse with a distinctive dapple pattern that his offspring and great offspring shared.

Forgot to mention the homozygous mare has had melanomas since she was two and her heterzygous youngsters do not have any yet. PatO[/QUOTE]

Matiz is a GG Gson of Ferzon lol… Most of his descendants are just called “Gainey bred” after Ferzon’s owner…(and I’d say the influence goes far beyond MN, since Wayne Newton, Al-Marah, etc all used offspring from his breeding)… very different from the McCoy bred horses (breeders of Ferzon) though. And the Tone Ranch horses (Fadjur, again bred by the McCoys) as the McCoys and Tones went towards the bays of the lines. A lot of the Al-Marah horses color that same grey now too… I think because of the Dreamazon influence. Anyway, I always heard it called “Gainey Gray” and here is a photo… The top photo is Gai Parada (son) and Ferzon. On the bottom is a link to Gai Monarch (by Gai Parada) showing the same greying. http://www.gaineyarabians.com/farm/history.html

similar lines are held by Al-Marah Quebec (Raffles/Raseyn/Rissalix) http://www.al-marah.com/stallions/amquebec.html … the lovely AM Power Raid is descended (sireline) from Ferzon, http://www.al-marah.com/stallions/ampowerraid.html as is the gorgeous TWS Gai Phoenix, http://www.twsarabians.com/TWSGaiPhoenix.html …

funnily, similar breeding way back, (2nd stallion down) is a very McCoy bred stallion… http://www.twsarabians.com/Otherstallions.html and in the Tone Ranch http://www.fadjur.com/stallions.htm and yet, very very different horses lol (though all gorgeous).

[Joie]

I have had four foals born since 2007 that are various shades of going grey. Three were out of the same mare, but by different stallions:

The 2007 born-dark bay colt STILL isn’t grey. He has just a small amount of roaning on his barrel. People think it’s from the sabino, but I know he’ll eventually be grey. His sire is bay sabino.

The filly from 2008 was born chestnut, and started to go grey almost immediately. Her sire was chestnut.

The 2009 colt, born dark, dark bay is starting to grey slowly, but not as slowly as the 2007 colt. It is apparent that he would be grey at weaning. His sire was dark, dark bay.

Also, I had grey mare from the same damline as the above mare foal a colt by the same chestnut stallion as the 2008 filly. Like the filly, he was born chestnut and started to grey immediately.

Because the environment was the same for all of these foals, I would be inclined to say there are hereditary factors at work. It’s such a small sample that it probably doesn’t count, but it is amazing how different the process has worked for all of the foals.

[my_doran]

my horse was born a bright copper penny chestnut and greyed out pretty fast,by 1.5-2 he was a completely dapple grey…he is now just coming 5 and is just getting darker grey and in some spots he is already turning white.especially his face.
i think its genetic and maybe a lil on the enviro side…as warmer climates might make a horse dapple out more quickly.
i know a friends horse thats 11yrs and just starting to grey out.
JMO

[camohn]

not a study…but by cursory observation seems to be genetic. I had a gray mare that took a long time to gray out (9 years) and other siblings of hers by the same stallion as a whole also seemed to be slow to gray out. I have seen others (different bloodlines) that were nearly white early on.