As my mare sheds out I’m noticing quite the color change this year. She just turned 5 and this past winter her coat was much darker and healthier then before. As she’s shedding out I’m noticing white hairs starting around her flanks and up over her hind quarters. She’s got a few grayish mane hairs and quite a few in her tail. Is it possible that she’s a roan? I’m going to have to take pictures.
Flank and hind quarter hairs, especially combined with the white in her tail, is very indicative of Rabicano. No Roan 
For all intents and purposes, Roan doesn’t exist in TBs.
Hmm. What is Rabicano exactly? That’s a new term for me.
Googled it! I never heard of that before. Interesting but that does seem to fit her.
Rabicano is a untestable gene, or set of genetics, that causes white hairs in the tail, even if just a few, right at the top, but can be pretty obvious, aka “skunk tail”. When it puts white on the body (and if there’s a lot of white in the tail, there will nearly always be white on the body), it does it sort of back to front, but it DOES stop at the shoulders.
This is a very obvious skunk tail, aka Rabicano
This is very extreme Rabicano moving into the body - see how it stops at the shoulders?
My girls tail isn’t like that. Her tail almost looks gray in color or like its dusty. Her mane is almost completely black except for maybe two white hairs. But the white on her rump is getting heavier (I guess that’s the term to use).
I have an OTTB gelding that I suspect has Sabino/Rabicano. He has white hairs throughout his coat (heaviest in his flanks) and a mild skunk tail, along with a blaze and three whites and random black dots.
His socks are sorta jaggady looking and you can see his nose spot
One of these days I want to take better pictures and post him for confirmation since I’m not a color person by any means.
Mine has the same type of spotted sock and star/blaze/snip type facial marking.
Rebels, picture of your girl?
There is some evidence that Sabino may play a role in 'color shifting", including sort of graying out a tail.
I’m hoping she doesn’t decide to get too dirty in turnout today and I can get some decent pictures.
Best I could do this evening.
Right barrel
http://img.photobucket.com/albums/v654/Rebels_Princess/566DD793-78C2-4E4C-B121-DB9CC66765CF-8852-00000BC0460E8CDB.jpg
Messy tail - in heat. What looks red is usually grayish.
http://img.photobucket.com/albums/v654/Rebels_Princess/2C7A8E07-5E31-4B15-8BD2-76AE65B87B8E-8852-00000BC06B6FE51A.jpg
Kind of see the gray
http://img.photobucket.com/albums/v654/Rebels_Princess/6D72EB1F-0CC4-4861-BF31-B805CDCC95EB-8852-00000BC0767FC777.jpg
http://img.photobucket.com/albums/v654/Rebels_Princess/4AD07EA3-D8BB-4D45-8E55-787ED2FD0A0A-8852-00000BC08C84C021.jpg
Freckled nose
http://img.photobucket.com/albums/v654/Rebels_Princess/668B34AB-58D6-49BD-A3E5-2E6452911F82-8852-00000BC09E0AEF78.jpg
http://img.photobucket.com/albums/v654/Rebels_Princess/5C78ADF4-4408-4447-9D47-6C6639955CF5-8852-00000BC0A9B729EF.jpg
Just cause she was being nosey
http://img.photobucket.com/albums/v654/Rebels_Princess/4EE65206-99B0-42CD-AA11-7E7E455F9464-8852-00000BC0AFCCE2F0.jpg
Just her! Cause I find her adorable.
http://img.photobucket.com/albums/v654/Rebels_Princess/78328B49-705B-4E71-8831-65CA1FCCA558-8852-00000BC0C0016A48.jpg
I tend to agree with JB-- it looks like a bit of rabicano. I have one mare who is a solid black bay, and she stays dark even through the summer and doesn’t bleach in the sun. Her dam was by a stallion who was notorious for passing on sabino markings, but her sire’s bloodlines evidently squashed the sabino genes, as she doesn’t have a speck of white on her her. However, last summer into fall I began noticing little flecks of gray hairs throughout her body, just as you’ve described and pictured with your mare, and she also developed a bit of gray just around the dock of her tail. I’m almost certain this is the sabino trying to express itself through a bit of rabicano. I’d happily take some pictures to show you, but she’s still kinda in the phase halfway between woolly mammoth and slick greyhound. 
She’s still shedding small pony sized piles of hair too. So I’m anxious to see her when she’s completely shed out. It’s like getting a new horse.
Sabino can also put ticking in the body, and if you see that on the shoulders or neck, that’s likely what’s going on. But it can also put it farther back, which blurs the line between Sabino and Rabicano ticking/roaning.
The white/gray in the tail might be Rabicano, might not, it’s difficult to tell from these pictures
[QUOTE=JB;6945475]
When it puts white on the body (and if there’s a lot of white in the tail, there will nearly always be white on the body), it does it sort of back to front, but it DOES stop at the shoulders.[/QUOTE]
Does it always stop at the shoulders? I have a breeding stock (or whatever it’s called now) APHA mare with the white hairs in the tail and the white hairs scattered within the coat. Always assumed rabicano. However…the white hairs in her coat are on on her neck as well, and she has white hairs interspersed within her mane.
Yep, pretty much. If you’re seeing white on/in front of the shoulders then you can assume that’s from Sabino.
Looks like Sabino it is. As she continues to shed out she’s got white hairs on her neck now too. Will these continue to pop up more densely as she ages?
Probably both. The flank area is likely Rabicano, but the white on the neck is Sabino. She may get more roany as she ages, but it’s not a given. It’s probably going to be much less noticeable in the Winter coat than the sleek Summer coat.
Well it will be interesting to watch that’s for sure
I’m just smitten with this horse so I don’t care if she turns green with purple pokadots.
I’ll have to see if I can dig out old pictures of a TB a friend owned… He had the white rabicano hair throughout his entire coat, with the exception of his head and legs. They called him a roan, but I knew better… He had no other sabino markers - is there proof rabicano stops at the shoulders? This horse had no difference in the amount of white hair from shoulder to neck.
I’d say your girl is rabicano.
