Cedar Ridge, Grullablue, grullo, grulla, blue roan, quarter horses, AQHA, reining, Hancock, Blue Valentine, Hollywood Dunit, Topsail


Dun Factor Markings

dorsal.JPG (10793 bytes)

Copyright Note:

Please note that all of the text information on this page was originally composed by me unless otherwise referenced, and was typed with great thought.  I have read books and many educational web sites to contribute to my knowledge base.  Some of the content was created in the late 1990's, and may need to be updated. With 300+ pages in this web site, I can't remember which pages need updates all the time. If you see an out-of-date page, let me know so I can update it.

Some photos were donated by people that have horses with color examples needed to provide educational content. For that reason, permission is not granted for anyone else to use photos from these pages.

Please feel free to link to this page, but do not copy the content and place it on your site.

Click here to learn more.

There is often a great difficulty determining a horse's color when it comes to dilution genes, especially as foals.  Because of countershading, sooting, and other color modifications, foals are often mislabeled as duns or grullas when they really should be registered as buckskins or blacks.  See the bottom of www.grullablue.com/grullocolor.htm for photo examples of foal coat colors that can easily be mistaken for dun/grullo colors.

But as horses shed their foals coats, it should become more readily apparent if they carry the dun factor trait or not.  Photos below show some of the dun factor traits to look for.  Not all dun-factored horses will have all traits, but in my experience, all of them have had the CLEAN and CRISP dorsal stripe and the ear tips.

Why is it important?  Why should anyone care?  Because if a horse is being sold and is misrepresented (purposefully or accidentally) as being one color and it truly isn't that color, then it reflects badly on the seller when the truth is found out. It can also be very disappointing to the buyer.  I have heard of too many instances of this...both purposeful and accidental, that have both hurt seller reputations and damaged buyer's pocketbooks.  The largest case occurs when a buyer pays a higher price for a rare color, such as grullo, only to have the horse shipped home to see for the first time in real life and find that it is a buckskin, black, smoky black, or gray.  

Dorsal Stripe: This is a required dun factor marking. If a horse lacks this, then it is not a dun or grullo. The dorsal stripe is a dark stripe running from the poll to the dock of the tail. It shows up along the horse's spine. Though it may have barbs extending off of it, it will have CLEAN and CRISP edges, and won't "gradually fade into the body color of the horse."  It will also be an "intense" color, and does not fade away in the summer.  It should not be a mixture of body hair color and dark hair color, but should instead be uniformly dark throughout. dorsalreddun.jpg (4714 bytes)  dorsal.JPG (10793 bytes)
Dorsal stripes on red dun (left) and grullo (right)
Ear Tips: The ear tips are generally the same color as the dorsal stripes. Sometimes the entire ear will be rimmed or edged, but the actual ear tip is when the top half or third is dark on the back of the ear.  All duns/grullos that I have seen have had ear tips.

NOTE: Dark "rims" around the ears (viewed from the FRONT) are NOT dun factor markings. These dark rims are common in bays, buckskins, etc. and are NOT caused by dun factor. See the diagram at the right for an example.

Ear tips on a foal, left.
The drawing at the right shows ear tips (top 2 sets of ears), which ARE dun factor related.
The bottom set of ears shows ear rims which
are NOT necessarily a sign of dun factor.

Leg Barring/Zebra Stripes: These are horizontal tiger stripes that appear on the legs, usually around the knees and hocks.  These are not always present on dun-factored horses. dunalinolegbar.JPG (7597 bytes)  bars.jpg (8160 bytes)
Shoulder Stripe & Shadow: A stripe or a shadow coming off the dorsal and crossing down the withers toward the ground.  Some are thin, some have multiple stripes, and some are just shadows. shouldershadowfoal.jpg (6997 bytes)  Thanks Karen R. for the picture!
Face Mask: Duns of all shades usually have a darker mask on the front of the face or over the bridge of the nose than on the rest of their bodies. 
Mottling: Some duns will show mottling on the arm and shoulder or gaskin and stifle. Mottling appears as dark splotches about the size of peas when viewed up close, or like tiny reverse dapples. mottling.JPG (13330 bytes)
Mottling (above the leg bars) on a dun
Neck Shadow:  Similar to shoulder stripes at times, neck shadowing can be definite striping to sooty-looking shading coming down off the top of the neck.
Frosting:  Frosting in the mane can be subtle or very pronounced, as on this grulla mare.  Frosting is light coloring to the mane hair on the edges of the mane. The "main" part of the mane is black, but the hairs that run down the sides of the mane are light. frosting.jpg (2815 bytes) 
Silver grullo with frosting.  Zebs Blue Revenue, left.  Frosting on a mini, right ("Little Foot")
Cobwebbing: Stripes that resemble a spider's web on the forehead of a dun-factored horse.  Cobwebbing is very difficult to catch with a camera.
Click to view close-up shots of forehead cobwebbing. 
Dark Points: The legs will usually be darker than the body...similar to the mane/tail and dorsal stripe. points-red-dun.JPG (19428 bytes)
Dark points on a red dun:  note that the legs, mane, tail, and face are not diluted (lightened) by the dun dilution gene.
Barbs off the dorsal stripe:  Some dorsals will have barbs that extend perpendicular to the stripe and head down the rib cage.  These are not required, and vary in length.
Barbs on a dorsal strip
Guard Hairs: Some duns will have light-colored hairs at the base of the tail that can extend down the sides of the tail, called "guard" hairs.  They appear to be different than the white "skunk tail" that is associated with some roans' and rabicanos' white tail hairs. guardhairs.jpg (10981 bytes)
Note the light hairs on the sides of the tail at the top.
Silver Grullo foal eye color: This isn't a dun factor characteristic, but I thought I'd throw it in.  We've had several foals that had a sire or dam who carried the cream gene.  We feel that blue-gray eyes like this at birth indicate that the foal likely carries the cream gene.  Some grullo foals with the cream gene end up silver, but not all of them do.

Countershading (NON-dun factor striping)

The following table contains photos of horses that are NOT dun-factored horses.  "Countershading" is a form of striping that is probably a remnant of primitive camouflage, but which is not the same as dun striping.  It is not a dilution, and may only be visible on young horses. Some horses will retain some countershading for their whole lives, but it is far less distinct and contrasting with surrounding colors when compared to dun factor striping.

Not Dun Factor
This bay foal has a good example of a countershading stripe.  There are NO duns in his background, so we know he is a bay with countershading.  Most likely, his stripe will disappear when he sheds off as a yearling.

Not Dun Factor
A black foal with countershading-caused dorsal and shoulder barring.
Click here for proof that this filly is not dun factored.

tuscarorastablesdotcom.jpg (7392 bytes)
Not Dun Factor
A black foal with countershading.

Not Dun Factor
DNA tested buckskin with NO dun factor gene.

Not Dun Factor
This foal is bay or bay roan, but has an amazing countershading stripe and shoulder patch that will disappear over time. He can not be a dun, as he does not have dun factor genetics behind him in the pedigree.

Not Dun Factor
Super pictures of buckskin foals with countershading stripes that are not caused by dun factor. Notice that the dorsal on these foals stops abruptly at the top of the tail. The foals also do not have ear tips.

Neither dun factor nor countershading.

These are not stripes. This is a hair pattern that shows up best on black and blue roan foals' back legs, and that many people mistake for leg bars. It is not, and is probably a trick of lights on waved/curly hair.

Not Dun Factor

Countershading stripes on black and smokey black foals' legs are fairly common, but disappear over the first year.

UC Davis Information about Dun and Non-Dun Stripes

Three variants in DNA sequence explain phenotypes (how horse "look" to the eye) related to Dun dilution:

  • D (presence of dun dilution and primitive markings)

  • nd1 (not Dun-diluted; primitive markings are present but expression is variable). Think of "nd" meaning "not dun."

  • nd2 (1,617 bp deletion, not Dun-diluted, primitive markings absent). Think of "nd" meaning "not dun."

  • With respect to variant interactions, D is dominant over nd1 and nd2; nd1 is dominant over nd2.

  • The VGL offers a DNA test that will provide information for both dun dilution and the primitive markings. Click here for more information.

Show What You Know!

The pictures below show examples of horses that may or may not have dun factor. Can you get the colors correct by looking at these pictures?

Interesting picture, below. It shows how hard it is to guess horse colors when you can't see "the whole picture" through multiple photos, seeing the horse in person, and/or knowing the sire/dam genetics.

Without looking anywhere else but at this photo, what colors do you think these two yearlings (below) are?

Click the photo above to enlarge it.
Photo will open in a new window.

Then click HERE to see if you got it right!

Click the photo to view it full sized.
3 dun factors, one countershading (non-dun).
Can you tell which is NOT a dun factor dorsal stripe?

2 dun factors and one non-dun striping. Which isn't a dun stripe?

Click here for the answer.


What color is YOUR horse?

If you are trying to determine the color of your foal or horse, keep this in mind:  

The most common mistake people make
is in trying to force others to believe
that their foal or horse is the color they WANT him to be.

Many, many people have asked me over the past few years what color their foals were, and then have refused to accept my opinion because they so badly wanted their foal to be a different color.  As you try to figure out your foal's color, leave your personal preference out of it....go by the facts first.  Hopefully, you'll be pleased in the end!  But if not (for example, if you wanted him to be a grulla and he turns out to be a sooty buckskin), take comfort in the fact that you know the truth and can educate others about the differences between similar colors.

Click here to Request help determining your horse or foal's color

Please visit our web site at www.grullablue.com or Sharon Batteatte's site at http://members.aol.com/battyatty/dunfoal.htm or e-mail me at tonip@frontiernet.net for more information or more contacts.  

Color and Genetic Testing Labs

There are many laboratories in the US and around the world that do horse color testing, disease testing, etc. When you choose a lab, make sure it is a reputable one! There are several university-related labs, which I recommend, and many private labs (some of which can NOT be recommended!). Here are a few I'm familiar with:

University Laboratories:

Private Laboratories:

  • Animal Genetics, Inc. http://www.horsetesting.com/Equine.asp

  • Pet DNA of Arizona: http://www.petdnaservicesaz.com/Equine.html ONLY tests for Brown in horses (1/2010)

    DNA Diagnostics (aka Shelterwood Labs, and also affiliated somehow with Catgenes.Org)
    http://www.dnadiagnostics.com/  DNA Diagnostics/Shelterwood Labs offers a test for multiple characteristics at one price. I had seen a fair bit of chatter online about how they cash the checks and don't give the results of  the test. So, I tested them by paying for three horse tests. Guess what...they sent back two of my horses' test results and after 4 1/2 months, the third was still missing in action! Repeated phone calls and e-mails were ignored by the lab. Finally, five months after the test, someone gave me the results for the third horse. 
    If you choose to use this lab, my opinion is to only send them as much money as you are willing to lose, in case you don't receive your results. Update: A friend just called that used this lab and she still hasn't received her results after many months of waiting, phone calls, and e-mails. 3/2010. I know of another horse that tested homozygous for black that is not homozygous, as he has produced sorrel and palomino foals. In both cases, Shelterwood does not return their repeated phone calls.

REFERENCES:  This information was pulled out of my own brain in 2003, but my brain gained its information over the course of many years from internet sites, discussions with color genetics gurus, and from Equine Color Genetics, by Dr. P. Sponenberg, Ph D.  Special thanks to Linda Coehoorn, Kris Enloe, IBHA, and Sharon Batteatte for helping me understand the genetics of the dun and grullo colors in the mid 1990's.   

How To Donate Your Educational Photo:

  • If you are wondering what color your foal is, click here. We are having a lot of people send us pictures for this page where it is obvious that the foal owners don't know what color their foal is. Please, only send us photos for this page if you know your foal's color. If you don't know what color your foal is, click here.

  • If you foal is a Paint or Appaloosa, we will only use it if the vast majority of the foal's body is not included in the white patterned areas, as this page is intended to help people determine foal colors, so the colored hairs must be very obvious.

  • This is an educational page, and photos should show a safe environment and healthy horses. I don't even know how to respond when I receive photos of wormy, skinny horses in pastures littered with abandoned cars, farm equipment, wire fences laying on the ground, and falling-down buildings. I simply can't put photos like that on an educational page like this, where people come to learn.

  • Please note that this is not intended to be a free opportunity for you to advertise your breeding operation, and instead is an educational page. We will not use photos with watermarks/writing on them. There are many free advertising sites on the Internet at which you can advertise your farm/ranch/horses. Also, only send photos of foals you own. This way, there won't be copyright problems.

Feel free to click the "Send Your Photo" logo at the left
to send a good photo or two to us for inclusion on our color pages.



Photo Ownership Notice:
All of the photos on this page are the property of Cedar Ridge QH's or were sent to us with permission.
If someone has sent a photo to us for use on our pages that belongs to you,
and if they did not have permission to do so, please let us know.
If you are interested in contributing a photo, we thank you! But please do not alter the photo or place your contact
information on it. Our educational pages are for just that...education. Not advertisements. Thanks!


This page last updated 05/07/16
If you notice this date being 2 years or older, please let us know that we need to check out this page!

Home    Horses For Sale    Stallions    Mares    Foals    Blog    Color Genetics   Riding Horses    Site Map    Contact Us

Toni Perdew       Bedford, Iowa
712-370-0851 cell, before 9 p.m. CST  (NO telemarketer calls)

do not call us on the phone with color inquiries for your own horses.
See link to the Color Pages if you have a question about your own horse or foal's color.

Web design by CR Equine Sites.
All rights reserved. Graphics are watermarked for copyright protection.

Terms of Use