Dear Prism,
Hello. I have an AQHA filly that was born red dun with all of the dun factor characteristics (red leg barring, dorsal
stripe, red mane and tail). Now, as she is shedding her baby fuzz, she is black underneath. She has three white stockings, and so
far I cannot see any black coming through near her coronet band on her solid colored leg. However, every place else on her body
where there is a nick or scrape, she looks very black. Where she is shedding out around her eyes and muzzle, she is almost black.
The sire was a dun with black points, and the mother was a brown/black out of a black sire and sorrel mare. Any ideas? Thanks
for your insight. – Submitted by Melissa K. Miller via HorseGazette.com
Dear Melissa,
Congratulations! You have a “Surprise Package”. One of the reasons I love foals so much as one rarely knows what
they’re getting until the yearling coat shed off. Since both parents are black based they obviously carry a red-gene each (the filly
was born Red Dun). Without pictures I really can’t take a learned guess but I’m going to say you’ll end up with a shade of red,
won’t comment on the “Dun Factors” as many foals are born with what looks like Dun factors but are in fact Counter shading. I
will say if she was going to be black based, the solid leg would be showing black color. - Prism
Dear Prism,
What colour stallion should I breed to a black mare to get a dun or grullo foal? I think that the mare may be
heterozygous for black as her body fades to dark dun in summer (including dark golden flanks, and she has red lights in her mane
and tail, although her points remain black. Also is it true that the agouti gene is dominant, so if a horse has received it from only
one parent, it will affect the colour, but it will not necessarily be passed on to the offspring? Submitted by Tracy via
HorseGazette.com
Dear Tracy,
You would need to breed to a Dun stallion to introduce the Dun genetics/markings into the mix. You would still have a
50% chance of the resulting foal being a dun. As far as the black status of the mare – easy way to know is to have her tested.
Pull mane hairs and send to a lab for the “Red Factor Test”. The test will let you know if she carries the red gene or not. As far
as the Agouti? Agouti only affects the black color so many red horses carry agouti but you would never know without testing.
And yes, Agouti is a dominant gene and just one copy will give you a Bay horse instead of a Black horse. As with all genetics –
when one copy of a gene is present there will be a 50% chance of that parent passing along to the offspring. - Prism
Dear Prism,
I have a filly whose dam is palomino and sire is black/bay. The filly is a very light sorrel with lighter legs belly and
chest. I have seen pictures of foals this color that are advertised as palomino. How do I know if my filly will turn palomino or
stay sorrel? Submitted by Bridget via HorseGazette.com
Dear Bridget,
Easiest way it to have her tested for the Dilute/Cream gene. The filly had a 50% chance of inheriting the dilute/cream
gene from her mother. Another way would be to look at the mane/tail of the filly – if she is a Palomino the mane/tail should be
an extreme flaxen or white color. I’ve seen many different horses of different breeds advertised as Palomino when there was no
way they could be – I’d test her to know for sure. - Prism
Dear Prism,
I have a Grullo Stallion and I'm not sure if he is heterozygous for the black gene or not, since I have not had him tested
just yet. What color mare would I have to breed him to in order to get another grullo? Just the same, what are some other
possibilities for his breeding with other colors? Submitted by Krista Rougeux via HorseGazette.com
Dear Krista,
Well, Grullo is Dun on a black base with no Agouti present. Since you don’t know his red status we will assume that
he carries a red gene as well. Your best bet to get a Grullo foal would be to breed him to Grulla mare. The mare would also be
Dun on a black base with no Agouti (which limits black to the points). This should also minimize chances of a red foal as well.
If your stallion is homozygous for black you will never have a red foal regardless of the mares he is bred to. So your color
possibilities for foals out of your stallion would be Sorrel/Chestnut, Red Dun, Black, Grullo, Bay, Bay Dun, I’d have him tested
so you know exactly what you are dealing with in the breeding shed. - Prism