Can someone point me to examples of red bay horses that are homozygous for dark coats? Or is red bay an indicator the horse carries the chestnut gene?
It seems every red bay horse I have ever known had a chestnut parent (at least, the ones where the parents were known).
That has been my experience. I love the red bay color, but I also prefer mares that don’t carry a red gene (foolish, but I will admit it). Every beautiful red bay that I have bred had a chestnut parent or had two bay parents but when tested was shown to carry a chestnut gene. Most of my dark, dark bay mares are homozygous dark. One of my black mares is homozygous dark and the other carried a red gene.
I know nothing of genetics.
My mare is classified as a red bay. Here is her pedigree. Neither parent is chestnut.
http://www.allbreedpedigree.com/passion30
[QUOTE=Burgie;6701090]
I know nothing of genetics.
My mare is classified as a red bay. Here is her pedigree. Neither parent is chestnut.
http://www.allbreedpedigree.com/passion30[/QUOTE]
Ah, but both parents carried the chestnut gene, as they both have a chestnut dam 
Your mare has a 66.6 % chance of having the red allele.
Well, that 66.6% red certainly explains quite a bit about my mare!
Interesting question! That I don’t have an answer for.
But I will say that I bred to this stallion , and was expecting a pretty dark bay foal with some white socks.
…but the dam is chestnut and I got a bright red bay foal (not complaining, just not what I expected).
https://sphotos-b.xx.fbcdn.net/hphotos-ash3/614638_4124650848819_546325485_o.jpg
Nope, no correlation at all between Ee or EE, and the shade of bay.
I DID have my hands on a link to the study that showed that, but it’s missing in cyber land, so as soon as I can find it again, with the help of my friend who first showed it to me, I’ll be back.
As a side note, there IS a correlation between Ee and EE, and the amount of white Black tends to suppress white expression in Overo and Appy patterns, and EE is likely to be more suppressed than Ee.
As well, Agouti seems to have a sliding scale of white suppression, with aa having the most, Aa allowing some more, and AA (whether that’s At or A, I don’t think the study differentiated) having even more.
I am not familiar with the term red bay. Would this mare be considered red bay?
Might see color different but do you mean orange? And what are the factors that affects the “color” of bay? If A suppresses the black (E), is it possible that the e might affect the color or if it is Aa or AA. (more or less suppression)
Nor sure about the source…http://www.bio.miami.edu/dana/dox/horsecolor.html
bluemoon, yes, that’s pretty close. A “real” red bay looks very red in his body color.
stoic - not really orange, but not really NOT orange LOL It really does look very red.
It is unknown what factors affect the shade of bay (or chestnut for that matter). It’s probably a combination of factors though.
Ee does not affect the color any more than EE does, which is (apparently) not at all. The Ee horse is no different from the EE horse because neither of them tell the body to produce any more or less pigment. It’s the Agouti which is telling things where to limit the black pigment and, in the case of Wild Bay for example, it can even dilute the black a little bit. It’s not common, but some wild bays have manes and tails which are a bit sooty-looking, very dark gray looking to some, and even the lower legs (which have reduced black height) can have the black lightened a little.
That link is very outdated in many ways, if it was even based on any research and not just someone’s observations 
“brown bay” does not exist, though there were several terms used to describe the (what we now know genetically is) brown horse - dark bay, black bay, and even brown bay. But A? (as they say, A-) doesn’t tell you genetically what the horse is. In their “brown bay” picture, the horse is clearly brown, and his A- would test as either Ata (heterozygous for brown), or AtAt (bay is dominant over brown, so A and At can’t exist together in a brown horse). His Extension status had nothing to do with his shade.
But, that red bay horse in the link is the stereotypical red bay. How orange or red he looks is going to depend on your monitor and your eyes
[QUOTE=JB;6701444]
As well, Agouti seems to have a sliding scale of white suppression, with aa having the most, Aa allowing some more, and AA (whether that’s At or A, I don’t think the study differentiated) having even more.[/QUOTE]
I get what you mean here, but I can see that it might get confusing so I’m going to reword it a little bit. AA has the least white suppression Aa has a little bit of white suppression and aa has a lot of white suppression.
Ah, yes, I can see how what I wrote could be taken to mean the opposite, thanks.
Thanks JBP. One of the first horses that I bred is chestnut with socks to the knees and hocks and a slim blaze. Dam is black with two anklets. The sire bay with minimal white. I gave up on trying to figure out colors after that!
Oooo, picture of the chestnut? Just 'cause I like to see all that white
Black tends to suppress white markings. So, the 2 black-based parents would likely have had more white if they’d been chestnut. Then, the 2 of them probably caused a cumulative effect (different from a homozygous effect) of the white for the foal, PLUS made the foal red-based, and voila, lots of white
My gelding is a bright bay. His sire was chestnut ( http://sporthorse-data.com/horse/527529/668/Horse_Vas_Y_Donc_Longane-big.jpg ) and according to his papers his dam was bay (not sure of shade or markings).
He looks like this:
http://sphotos-a.xx.fbcdn.net/hphotos-ash3/534727_4830860298145_2137907513_n.jpg
no correlation at all between Ee or EE, and the shade of bay.
Thanks for the info. I know about EE, Ee, ee, etc., and their relationships to each other - but as I mentioned, it seems every red bay I have come in contact with, where the parents where known, had one chestnut parent. And since (so I hear) red bay isn’t well understood, I wondered if there might be some yet to be discovered factor at work.
Here are a couple of pix of the chestnut I have from a black and bay. Of course the only pic that I could find of his legs is from when he was 2 yrs old. The head shot is from this summer.
Is this foal red bay?
[QUOTE=DownYonder;6703373]
Thanks for the info. I know about EE, Ee, ee, etc., and their relationships to each other - but as I mentioned, it seems every red bay I have come in contact with, where the parents where known, had one chestnut parent. And since (so I hear) red bay isn’t well understood, I wondered if there might be some yet to be discovered factor at work.[/QUOTE]
Have a look at the Cleveland bays, there are a lot of homozygous black, red bays within the breed as a whole.
[QUOTE=bluemoonfarms;6704597]
Is this foal red bay?[/QUOTE]
Denise, he does look red bay in the photo. The dam also looks almost liver chestnut in that photo, but I can see that her legs look black, so I assume she is either a mahogany bay, or the photo had a reddish tint to it. Is the sire also bay? Do you know if either dam or sire carry a chestnut gene?
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