Gray immediate parents who produce non-gray foals

[Jorge]

Apropos another quite interesting topic being discussed here (regarding "TB color") I would like to ask your opinions and comments on the rare (but normal) occurrence of...

GRAY IMMEDIATE PARENTS PRODUCING A NON-GRAY FOAL.

(Cases like the sprinting great son of Runaway Groom named Cherokee Run)


Please share your stories.


Here's a comment on this topic: Have you noticed the relatively great amount of black equines who are foaled from a gray parent with a non-black mate? I always wonder if these black equines outnumber the total of black equines foaled from a single black parent. Any study done?

Thanks for your participation!

All the Best,

[summerhorse]

I think a lot of greys are black or brown based and probably just happened that way because a lot of TBs are black or brown based. I think in general though more blacks come from blacks or browns crossed together. (just an observation)

Grey is simple though. It is a simple dominant. One parent must be grey G. There is no phenotypic difference in homozygous GG and heterozygous Gg (although some theorize that heteros are the ones that get flea bites and that homozygotes grey out faster but I don't know that anyone has every actually collected enough of a sample to prove that one way or the other).

Because TBs are generally bred without regard to color most grey horses are heterozygous for grey so they have a 50/50 chance of passing it on (assuming bred to non grey mares!). So approximately 50% of their lifetime foals will be grey and the other half non grey.

if the horse is homozygous for grey then ALL the foals will be grey regardless of the mare color.

Breeding two heterozygous greys together gives you more chance at grey (25% homozygotes, 50% heterozygotes and 25% non grey). So you just have more opportunities for grey to get passed down. BUT because each foal has the same chance at the coin toss you could still end up with all greys, no greys or any combination in between. As you get more foals for a stallion the percentages will start to even out but for a mare who only has at most 25 foals lifetime TOPS for TBs (I'd tihnk) that just isn't a high enough number to get a good statistical summation.

Of course breeding a homozygous to a heterozygous will still produce all greys and half will be homozygous and half heterozygous.

If a breed is selected FOR grey as in Lippys, camargue (think they are all grey now), andalusian, arabs, etc. you will have a much higher % of homozygous greys than in the average breed not selected for color at all.

I don't know of any homozygous grey TB stallions offhand but I'm sure there are some.

[Evenheaven]

We owned a grey mare, I Truly Sparkle, and she only had one grey foal in 1995 when she was bred to a grey stallion. Her other breedings were to warmbloods, but she never had another grey foal. All the other wb stallions were either bay or chestnut. I guess she would be hetrozygous for the grey gene?

[summerhorse]

We owned a grey mare, I Truly Sparkle, and she only had one grey foal in 1995 when she was bred to a grey stallion. Her other breedings were to warmbloods, but she never had another grey foal. All the other wb stallions were either bay or chestnut. I guess she would be hetrozygous for the grey gene?

Yup!

[Jorge]

A friend and breeder just wrote to inform me that she coincides with my impressions that Runaway Groom has an unusual tendency to throw more than expected non-gray equines when mated to another gray mate. Hmmm, never read or heard on that angle.

[xfactor fan]

Jorge,

When you mention the high percentage of blacks from grey matings, are you talking about foal color, or final adult color?

There's an old saying that all blacks are born grey, and greys are born black, which reflects the mouse color that many black foals show before sheding out to their adult black color. Greys do the same thing in reverse, with the grey gene darkening what ever coat color is expressed before the horse turns grey.

So someone on a stud farm who is looking at lots of foals from their grey stallions might very well think that there are lots of blacks being born. They might not see the horse as an adult in their grey or white coat color.

[CA Michael]

I bred a grey Relaunch mare to my grey stallion three times, and she produced two greys and a bay. The stallion is sired by a grey, out of a bay, who in turn is sired by a grey. He has produced approximately 75-80% roan/grey horses, 20% bay. No chestnuts. Virtually every chestnut mare I have bred to him has produced bays (don't know about other breeders' though).

[Jorge]

I was referring to officially registered black equines coming from crossess where one of the parents is a gray VIS-A-VIS officially registered black equines coming from crossess where one of the parents is a black.

But perhaps the easiest way to ask the question is: How immediate parents who throw a black foal are distributed in terms of percentage?
That is:

01. ___% percent of black foals coming from two solid color
parents.

02. ___% percent of black foals coming from a solid color
and a gray parent.

03. ___% percent of black foals coming from two gray parents.

Etcetera.

In synthesis, I am under the impression that cases coming from the second alternative may be a little bit higher than the average ---but not by much! The difficult thing in trying to analize this data seems to be the small number of black equines produced each year. Perhaps a historical study may better help establish a theory.

[summerhorse]

I think that would be impossible to say really because so many blacks are mis registered as dark bay or brown or just brown.

[DLC]

As far as homozygous grays there have been two that I know of in the Ocala area. Darn That Alarm (deceased) by Jig Time was homozygous gray and Wekiva Springs (still standing at Double Diamond) by Runaway Groom has sired only gray foals as far as I know.

[Jorge]

STRONG PERFORMANCE (standing in Texas, I believe), who is a full brother to DARN THAT ALARM can be added to the list.

By the way, let me share with you a question I have asked myself about DARN THAT ALARM and his gray lineage: If someone tries to rule out which gray lineage(s) of DARN THAT ALARM are not responsible for his gray coat color, how would you proceeed to do it solely based on visual hints ---namely, tricks of the trade? I can only make reference to "visual hints" because according to science, this attemp would be impossible to determine from a genetic point of view. My purpose is to try to determine if Darn That Alarm's gray coat color is due to Native Dancer or not.

[pokeyman]

It's not that rare at all. In fact, most greys are heteerozygous so are black, chestnut, or bay recessive. So, there is a 50% chance any foal will not be grey by these parents.

I don't know too many TB that are homozygous grey...

[DLC]

Jorge,

That's interesting....I was aware of his brother in Texas but didn't know he was also homozygous for the gray.... there must be something pretty unique in that cross as there aren't a lot of homozygous grays.

That's a tough one as far as visual hints. I won some "just for fun" bets on the color of some of DTA's foals. People would catalog weanlings in July for the October OBS sale here and they would be cataloged as brown or bay....
They would argue with me that the foal was NOT gray and I would tell them that it WOULD be a gray. By the time of the October sale they would all be starting to gray out and the color change announced in the ring.

So as far as visual there were a LOT of his foals that started to gray out much later than foals out of other gray parents. Not sure of this, but I have also noticed over the years that all of DTA's foals that I had seen were black based grays even out of many chestnut mares. So was he also homozygous for the black gene and couldn't sire any red-based foals???

Wish I had a better answer!

[Lucy]

Well, since Darn That Alarm was homozygous grey, wouldn't that mean he got the gene from *two* ancestors? Since you know one came down from Blazing Count, the real question would be if Jig Time got the grey gene from his sire or dam.

[Jorge]

Dear Lucy,

Thank you very much for your participation. That's precisely what I am trying to determine: Native Dancer (via Jig Time) yes or no! I have a theory: to study via photos how much Jig Time's gray hair design resembled that of his sire vis-a-vis his dame.