ChaCha!

[barbhorses]

"From: "Sponenberg, D. Phillip" <[e-mail]>
To: Kimberlee Jones <[e-mail]>
Sent: Tuesday, October 18, 2011 5:26 AM
Subject: Re: Color

I'm still gonna bet that these are not duns. That is, when mated to "regular" bays or blacks, they never give a really light dun or grullo. If they were duns, they should! That goes for the "dark grullos," and also for the stallion in the photo. The foal is a bit trickier, but I want to bet "bay" on that one as well. I wouldn’t have too many doubts except for the striping (weak though it is) on the legs. To me, the dorsal stripe seems like the usual "weak" stripe that some nonduns get – it seems to peter out towards the withers.
--
D. Phillip Sponenberg, DVM, PhD
Professor, Pathology and Genetics
225 Duck Pond Drive
Virginia-Maryland Regional College of Veterinary Medicine
Virginia Tech
Blacksburg, VA 24061
USA"

"From: "Sponenberg, D. Phillip" <[e-mail]>
To: Kimberlee Jones <[e-mail]
Sent: Monday, October 17, 2011 11:55 AM
Subject: Re: Color

well, most if not all duns have a "tan" shade to the color, rather than being really red. In addition the heads are usually darker than the bodies. And they should have some striping on the legs, as well.

A lot of optimists that are looking for duns get pretty excited about these linebacked bays – but they don't tend to reproduce it!
--
D. Phillip Sponenberg, DVM, PhD
Professor, Pathology and Genetics
225 Duck Pond Drive
Virginia-Maryland Regional College of Veterinary Medicine
Virginia Tech
Blacksburg, VA 24061
USA

E-mail: [e-mail]<mailto:[e-mail]><mailto:[e-mail]<mailto:[e-mail]>>
Telephone: [phone]
Facsimile: 1-540-231-6033

From: Kimberlee Jones <[e-mail]>
Reply-To: Kimberlee Jones <[e-mail]>
Date: Mon, 17 Oct 2011 14:03:39 -0400
To: "Sponenberg. Phil" <[e-mail]>
Subject: Re: Color

So, what does a dark dun look like then? People keep posting pictures of horses that to me look like bays with counter shading, but they keep on insisting that they are in fact dark duns.

That is really funny about chestnut colored horses! I didn't know that! lol

Kim

________________________________
From: "Sponenberg, D. Phillip" <[e-mail]>
To: Kimberlee Jones <[e-mail]>
Sent: Monday, October 17, 2011 10:51 AM
Subject: Re: Color

probably countershading (though it is strange that the body color is so clear). I doubt that the horse would pass it along.

One good way to make "duns," though, is to clip chestnut horses! Once clipped, lots of them have that dorsal stripe!
--
D. Phillip Sponenberg, DVM, PhD
Professor, Pathology and Genetics
225 Duck Pond Drive
Virginia-Maryland Regional College of Veterinary Medicine
Virginia Tech
Blacksburg, VA 24061
USA"

[barbhorses]

"well, most if not all duns have a "tan" shade to the color, rather than being really red. In addition the heads are usually darker than the bodies. And they should have some striping on the legs, as well."

This comment came from a Kiger in the pens that was posted on the Kiger FB page that appeared to have a dorsal (though no clear edges), but was a rich bay.

[barbhorses]

I agree that not enough is known about color. Where does the silver grulla and claybank colored horses get their modifier to be so light? I am sure you all remember that I had a claybank Spanish type Sulphur mare named Arista tested and was negative for silver, cream, and pearl. On paper, she may as well have been a regular colored red dun!

The interesting part though is the dun zygosity test not confirmed that the dark grullas are grullas. If the test was really "inconclusive", then I imagine that perhaps a few genes that they search for may have popped up, but maybe not enough or not all of the appropriate ones to indicate the dun factor genes. This is obviously just guessing, but it may be the reason why the horse is black with buff ears.

The "dark duns" seems to be easier to figure out as I am sure all of us have known about line-backed bays aka bay horses with counter shading that falsely appear to give a dorsal (the lack of clarity and a solid line being an indicator of a false dorsal per Dr. Sponenberg).

I think it also interesting to note that Dr. Sponenberg said that duns should have darker faces as well. I don't think he means overly dark like what you would see in a classic roan, but I know that Victoria's face is certainly a bit darker than her body.

I think that the only true test for these dark duns and dark grullas is to breed them to bays, chestnuts, and blacks and see if they can produce a classic colored grulla or zebra dun or red dun. So far, I haven't seen these dark grullas and dark duns being consistently bred to regular duns and grullas. However, when I have seen a mating between such pairs I have yet to see a classic grulla or zebra dun. Thus, no test has really been performed to see if these horses can actually produce a regular colored dun factor foal from a non-dun factor test mate. I would prefer to have many foals on the ground from test matings before I actually make an informed opinion.

I am excited about your future test foals Michelle as I also agree that something else is going on with the color, but I don't believe it is the dun factor. Will be interesting to see if I am right or wrong!

[barbhorses]

Interesting read on foal coat colors on this page: www.grullablue.com/colors/dun_factor_markings.htm

She shows pictures of horses with dun factor and horses with counter shading and sees if you can guess right!

[Michelle Clarke]

So, what does that mean to you? There obviously are plenty of black looking horse that are grullo, so sooty does affect that. As far as coyote dun...while there are a lot of brown horses around, there may not be a lot around in those particular breeds that dun is common - like Spanish horses. I know of some Kigers that surely would be considered as such.

Let's also not forget how much diet affects color. Horses getting high protein have richer, darker colors. This time of year my mares on the hill are super dark right now from eating acorns.

[barbhorses]

Michelle, you can see that the foal isn't a grulla as grullas are born with a buff coat and then shed out into a grulla.

[Michelle Clarke]

Not all the time...there are some cases where the foals are born grullo and turn into dark grullos when mature. As a matter of fact, Central Texas Kiger on this board, had one he sold. She was born grulla and stayed grulla.

[barbhorses]

Some great photos of foals that sport very convincing dorsals, but lack the parents or even breed that has the dun factor dilution.

www.duncentralstation.com/LookALikeColors.html

[barbhorses]

Interesting. Can you post a picture of this mare?

[barbhorses]

I am still going to agree with Dr. Sponenberg's opinion on "dark grullas" as he is the color expert. So, until proven otherwise that dark grullas or dark duns (meaning bays that look bay, but sport dorsal) can produce the typical zebra dun or typical grulla, I am just going to call them blacks or bays per Dr. Sponenberg's opinion on the subject. With that said, I am really looking forward to your test breedings of your dark grullas or your dark bays to regular black, bay, or chestnut horses and see what they produce. If they produce a typical dun colored horse then that will be extremely exciting and interesting! It might also make discovering the dun factor genes even more difficult... lol being that the dark grullas at Ravenseyrie didn't test positive for the dun factor genes that her typical grullas tested positive for.

[barbhorses]

Reading through the dun central information on dun factor I also found a very useful bit of information. The owner of the site said that horses with counter shading can change depending on the season. She has a lot of great pictures on there of horses that sport counter shading, but make very convincing duns!

[Michelle Clarke]

Food for thought...this mare does not have the normal dun appearance, yet has tested positive dun:

www.triplebhorses.com/lady_van_belle.htm

Especially check out her foal, Dually, at the bottom.

This stallion is homozygous for dun plus one cream. He should have a darker face but he has almost lighter, like what happens in buckskins. He also looks as though his dorsal is countershading in some pictures instead of a hard line stripe. He does not look like a typical dunskin...he looks like he has the sooty on top of everything else.

www.dunitslidinquarterhorses.com/dbs/stallion/details.php?horse=%3Cb%3EDUN%20IT%20OK%3C/b%3E&who=stallion

Check out his foals - all obviously carrying dun factor. The first one is very interesting in her body color. I especially like the pinto colored foal that is a dark grulla. She also carries the cream gene, hence the buff color when born, which is different from the tan color of most grullo foals.

www.dunitslidinquarterhorses.com/dbs/foals/index.php?who=foals

[barbhorses]

That mare still has a tanned (though dark) appearance with a very clear dorsal. I would say that she is a true dark dun.

Her foal is very interesting and doesn't look like the typical buff color, but a tan. I would have expected him to mature into a zebra dun and not a grulla.

Very interesting! However, the horses I have seen here or on FB that are proclaimed as grullas or zebra duns when they look bay or black has little to do with the mare and foal in the link. Counter shading (as seen above in the links I provided) can be quite convincing, but the horse lacks either the parents or the breed to even sport dun factor (which I think is the point, as you cannot have a dun foal without at least a dun parent).

I know we could sit and debate this all day, but I am really looking forward to the breeding of your dark grullas and dark duns to blacks, bays, and chestnuts to see if you can get the typical tan zebra dun and mouse grey grulla or red dun. How many foals do you think you would plan on producing? Maybe at least 10 for it to be consistent... I am just pulling a number out of the air there.

[barbhorses]

The "dark grulla" filly looks the same as Victoria during part of the summer. Victoria will darken up and then get lighter. I wouldn't say that she is the same thing as one of your dark grullas.

Very interesting stallion and if he didn't have the clear leg bars, cobb webbing, dark tipped ears, etc. he certainly would pass as a buckskin with counter shading! If you didn't look close enough at him then you could certainly say the he wasn't a dunskin. Good one Michelle!

[Michelle Clarke]

I thought we were talking color here, not you just trying to disprove my pictures once again, thereby I thought these links would be useful to show you that not all "rules" are consistent. As far as how many foals will I produce, I only need one dun factor foal to prove it - don't see what having to produce 10 foals has anything to do with it. It does not have to be consistent to be proven.

Once again, a nice thread just showing one of our young horses has turned into the color debate...