What's the chance of a bay baby?
Gray mare x Bay stallion
Gray mare's parentage = gray stallion and brown mare
Bay stallion has both dark bay parents.
First crossing made a gray foal. Would second crossing also make a gray foal or is there a chance of a bay? If gray is dominant in masking color, will there always be a gray baby?

A complicated question but I might be able to help. The AQHA has a handy color genetics book that you can download from their site. You might have to search for it, but I know it's there and it's free. From what I have you have to have one gray to get a gray. A bay will receive a bay gene from each parent. This means that a bay will always pass on black points regardless of the color of the other parent. The bay always carries a black gene but a foal will never be all black. So, I think that you could possibly end up with a blue roan. You could also have a gray and you might end up brown because the brown horse passes on a black gene as well. I hope this makes sense, color genetics are tough.

Do you know what color the mares base coat was before she turned gray?
Okay here what I figured out.

1. With out knowing anything background wise, just going off the mare being gray and the sire bay these are your chances= 75% gray and 25% bay

2. Now if the Stallion is unknown for the red factor and Homozygous for the Agouti gene(bay/black points) and we leave the mare unkown on the red factor and the Agouti and she is Homozygous for gray your results are = 100% gray

3. Stallion is unkown for red and Homozygous Agouti and the mare is unkown for red factor and Agouti and is heterozygous for gray chances are= 50% gray, 46% bay, and 3% chestnut.

But just plain on having a gray baby. These foals as you know are born bay, black or chestnut and turn gray. When the foal is born check around eyes and muzzle and on legs for random white hairs. If you see these good chance baby will turn gray.

Good Luck

What in the world. Now I understand why I just grab the welder and fix the waterers. Throw on my old roping saddle and go down the trail.

I think i just got a headache reading that stuff. But credit to you who know about it.

What if I wanted a Zebra?

You don't want a zebra. They are mean. Had to help castrate one once. Bad Bad Zebra!!!!!!!. We could just paint stripes on a horse if you want one that bad much easier. he he

Gray horses are funny! First off gray isn't a color. It is a modifier. You have to have a gray, to get a gray, same as dun! If you breed a gray to any other color you still have a 50% chance of getting a gray if the horse is hetrozegous. If it is homozegous you have 100% chance of gray. When I register my horses I always put Bay/graying or Black/graying, then you know the base color you are working with.
If you breed 2 hetro grays, you can get a 25% bay/black, 25% chestnut, and 50% gray. So if you are trying to stay away from gray. I like to have the none gray parent to have no gray behind them. This isn't 100% guarantee.
Your mare is probably hetrozegous for gray. But it is still just a roll of the dice. It is still 50-50% chance of gray.

Just thought some of you would like this color site to play with.

www.animalgenetics.us/CCalculator1.asp