Tag Archives | varnish roan

Repigmentation spots

Freckles2008

In the comments section of the last post, some posters noted the similarity of the white areas to fleabitten grey. That is not an uncommon thing with appaloosa patterns. Although it is easiest to think of the action of Leopard Complex (Lp) as a form of progressive roaning, where white hairs gradually replace the colored ones to form what American horsemen call varnish roan, in actual practice the process can go both directions. That is, it can add white hairs to lighten the coat, and it can add concentrated bits of color to speckle the coat. These darker hairs are sometimes called repigmented spots because they typically occur after the coat has already begun to roan out, or in an area that previously had white patterning.

The varnish roan mare at the top of this post is a very good example. I have run photos of Freckles before for the series of posts on appaloosa mottling. I have easy access to her, since she shares a pasture with my own appaloosa pony, Sprinkles. This particular image shows her coloring from four years ago, when the lightest parts of coat were an even mixture of white and color. At that time, had she not had such pronounced varnish markings on her body, and a sprinkling of dark spots on her hips, she might easily have been mistaken for a pale grey. (This particular photo was taken in early May, so she had not fully shed out for the summer and was just a shade or two darker than she would be in summer coat.)

Here is Freckles as she appears now.

Freckles2012

Each year she has gotten more pronounced dark ticking in the roaned areas of her coat, even as she gets lighter in the areas that were colored. This lighter ticking is most noticeable if you compare the right hind leg in the two pictures. The repigmented specks first began to appear on her shoulder, but over time they have spread across most of her body.

FrecklesCU

This close-up of her topline shows just how closely this resembles fleabitten grey. In fact, if I use Photoshop to remove the hip spots and what remains of her varnish marks, the resemblance to a true fleabitten grey is quite striking.

FrecklesFleabites

I suspect some type of repigmenting is part of what was going on with the roaned areas on the horse in the previous post. With Freckles, the flecking ties visually with what is already going on with her coat, so it looks less jarring. With the horse from the previous post, the odd transitions between his colored areas and the patterned areas make him look a bit like you pasted together parts of a bay appaloosa and a fleabitten grey.

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Partial blue eyes

Pintaloosa1ET

It can be really hard to get good shots of horse eyes, so I was really pleased to get a number of good shots of this Pintaloosa mare and her partially blue eyes. The placement of the blue segments certainly give her an unusual expression. This first image shows how her left eye has a blue section towards the upper front of her eye. The apparent shape is accurate – none of the bluish area is glare – since it is consistent across a number of images.

Here is her right eye, with a blue section on the lower side. Notice how a thin line wraps up along the back edge, and how uneven and inconsistent the blue area is. (The blue coloring on the left eye was uniform.)

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Here she is looking forward with her mismatched eyes, one with a blue bottom and one with a blue top.

Pintaloosa2ET

Here are some full-body shots of her, showing her varnish roan (leopard complex) and tobiano patterns. The varnish mark on the top of her tear bone is particularly noticeable in the first picture, and the mark across the nasal bones in the second one.

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PintaloosaFull

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Frosty roan

FrostyRoan1

I have one last variety of roaning to share. The mare in these photos is a Quarter Horse, and is what is often called a frosty roan. Like true, dark-headed roans, frosty roans have white hairs mixed in a dark coat, but unlike the true roan the hair is not evenly distributed. Instead it tends to concentrate more heavily on the topline, including the mane and tail.  On a true roan, the mane and tail remain dark.

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There are also concentrations of white hairs where the bones are more prominent. It’s hard to see because of the shadows cast by her saddle, but notice the pale area over her elbow. This can be seen on her hocks, too.

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She also has white hairs along her nasal bones. (I suspect the small white patch on the right side is a marking, and not part of her roaning.)

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In this way, frosty roans display the opposite pattern of white hairs than a varnish roan, which tends to retain color across the bony ridges. Here is a varish face with dark nasal bones and roaning on the rest of the face.

Abby

Varnish roans typically have paler hindquarters, but the other areas where a frosty would be pale, a varnish tends to be darker. Here is the body of a varnish roan, showing how the jaw, elbows and the hocks are darker.

Mottling1

There has been speculation that the gene that causes frosty roaning, paired with true roan, may be responsible for the very pale manes and tails on some of the European draft horses. Among those breeds, black, brown and bay roans often have markedly silver manes and tails. These are often more dramatic than the ones seen in ordinary frosty roans like the Quarter Horse above. That may be because the two genes interact, or it may be that the two are similar, but genetically unrelated. (The Brabant pictured comes from Wikipedia.)

800px-Brabanter

It is not unusual for visually similar colors, like roan and frosty roan, to end up combined in a population. When breeders find a given color appealing, there is often a bias towards selecting horses that have that color – or something that looks a lot like it. That is how breeders of “golden” Saddlebreds ended up with both champagne and palomino horses in their breeding programs. Having two (or more) different genes that produce similar effects can also increase the chance that foals have the desired color, because each gene is a separate chance to get the desired look. Unfortunately for those interested in horse color research, it can also make sorting out the underlying causes a lot harder.

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