Greying out - what affects the rate?

[kyanya]

I posted this in NL first but someone suggested it might be better in here.

I'm interested in what affects the rate at which grey horses change from dark to white? I've seen some horses with a white coat at 3, but others keeping their dapples until they're 10, and I was wondering why this could be? Is it genetics?

Does that mean that some breeds (and lines within breeds) grey out quicker, whilst others will retain their darker colouring for longer?

 

[KarynK]

Some recent genetic research has show that if a horse is homozygous for the Grey gene it will grey out faster.

Some coloureds and appaloosas appear to take longer before their coloured patches are lost and some greys can keep some coat colour in localised areas or by ticking and in some horses the greying process has been reversed in localised areas as well. I suspect that dapple greys are horses that would have exhibited dappling if they were not grey, so dark bays/browns with dappling.

Quite a bit still unanswered really!!

 

[horses13]

The whole colour of coats thing confuses me.

 

[fleabittengrey]

No constructive post but will be glued to this thread. I had an iron grey 2yo who is now nearly white at 4 with darker dappled barrel, and dark points. However all white bits are heavily fleabitten- which I thought didn't come in till later. My other fleabitten (see the user name!) was white with a dark mane at 10, the mane lightened from wither to poll, and the fleabits appeared - more and more each year.

Both TB, both had lots of greys in the parentage?

 

[kyanya]

It really interests me - I love dapple greys but it baffles me how some seem to keep that colouring for ages and some go white so soon.
And also, why don't any of the other colours change over time? I know roans change seasonally, but it's not a gradual change towards a final state, like greys

 

[sallyf]

Will watch this thread with interest but.
My Hetrozygous grey mare was white by the time she was 4 having been born bay.
She had 4 foals, 3 bays and a grey mare who was born nearly black but with a brown muzzle.
she would have been classed as a very dark brown based grey and now she is 12 she is still heavily dappled.
She has to date had 3 foals to a hetrozygous black stallion.
2 greys one a black foal who is now 4 and still what looks like black roan but obviously grey and a yearling who was born the same black with a brown muzzle as her mother so a brown based grey again.
The yearling is just as her mother was and i think will grey out at exactly the same rate.
The other now three year old is black i would guess again hetrozygous but not tested.
So to date although we started with a pale grey everything since has been dark and all only have a 50% chance of throwing grey.
So hoping for next years to be black again

 

[fleabittengrey]

It really interests me - I love dapple greys but it baffles me how some seem to keep that colouring for ages and some go white so soon.
And also, why don't any of the other colours change over time? I know roans change seasonally, but it's not a gradual change towards a final state, like greys

And why is it that feeding certain additives, I *think* things high in iron, can keep the dark colour longer?

 

[KarynK]

...
And also, why don't any of the other colours change over time? I know roans change seasonally, but it's not a gradual change towards a final state, like greys

The only one that progressively whitens is Appaloosa varnish which again has different rates, but it does not affect the spots only the areas of solid colour and not all of those.

Some "roaning" type coat ticking thought to be from the dominant white family can increase but very slowly and not extensively and true roan's can be born quite dark but the fact that they are a roan is usually apparent at foal coat change or after their 1st winter.

Grey is unique in that it is not a colour, it is a mechanism that prevents colour being produced, but in some horses at least a small part in that process can be stopped and in some rare cases reversed locally. It could be that the appaloosa process has a similar action to the grey mutation but without the melanoma effect, but proving that is a long way off!!!

The scientists are only scraping the surface of horse colours at the moment and there is still much to learn including what factors influence how and how fast a horse grey's.

 

[tuppence's fortune]

some appaloosas loose there spots most of the 99% of the time it is due to genes alot of owners of appaloosa stallions refuse to put there stallions to a grey mare as the foal even if spotted when born will alot of the time loose its spots within about 8 years. i had a blanket spot which was black when bought and by 3 he was light grey with lots of spots he is now 12 and he is just grey and has no spots at all. he was out of august dekota (appy stallion) and a grey cob mare. it just depends on genetics


www.whitehorseproductions.com/equinecolor.html

this website may be helpful for you to answer some of your questions better.

 

[amage]

My "white" mare was dappled across her bum with a dark mane and tail when I got her when she was 9. Then progressed to fully white while maintaining a dark mane and dark top of her tail by about 12. Now 14 and after weaning her foal about a month ago I clipped her to find her spotty! Technically fleabitten but the brown spots are bigger than average fleabitten. I'm not great on the genetics of colour but I do now she was born chestnut and her colt who is starting to go grey is a liver chestnut currently, the same colour as her spots and has the same black hairs through his mane so I'm guessing he may hold onto the same dark mane.

 

[bj_cardiff]

My Foal turned from bay to Grey in about 4 months.. pics below.. My 5yr old grey mare is still very dark tho..

 

[jamesmead]

Fascinating thread; have wondered this myself. My TB mare was a very dark iron grey and when I first saw her (she would have been 4 ) was just speckled with white. By the time she was 6 she was obviously grey but very dark with small dapples. Her first foal was very dark - looked virtually black, though this was just latent greyness; genetically I think she would have been bay or black and tan? - and after a first sprinkle of white hairs, stayed this way for years. When she was 6 she was still dark and undappled. A photo of her as a 9 year old however, showed her as being the same shade and with exactly the same coat pattern of dapples, as her mother at 6. Both were heterozygous. The original mare's other daughter is bay (black and tan?), dark in winter, paler in summer, and heavily dappled when changing her coat; but her dapples are bigger and impermanent.