Equine Colours

In the hope of not boring you all, I`d like to bring a little bit about equine colours to the table. I was making notes for this Horse Ownership course, and after listing the usual black, bay, chestnut, piebald, skewbald I thought I`d better check for any rare colours.

To cut a long story short I found a site about equine genetics, which touched on cream dilution, my personal favourite silver dapple as well as many others.

The gene which attracted my attention was the Rabicano gene. This gene causes limited roaning pattern in a specific pattern on a horse, and is usually characterised by the “skunk tail” effect, which is when the top of the tail has white hairs. I know one horse who has this feature – Otis.
He`s always had the white tip to his tail, and I`ve always said he`s almost a bay roan due to the speckling of white hairs over his body. So I continue reading this article, only to find that another feature of a horse with the Rabicano gene is sporadic white hairs around the flank and abdomen. Furthermore, the skin of rabicano`s can be mottled with pink, particularly around the abdomen and groin. Guess what! The soft skin of Otis`s abdomen and hind legs is mottled pink, and this gene explains why his barrel is more flecked with white than his neck and legs.

I found this fascinating, as it explains a lot about Otis`s looks.

Upon further reading I found that horses can carry both rabicano and roan genes, but rabicano colouring is rarely extensive enough to be confused with the roan colouring. Additionally, horses can carry the rabicano gene and the sabino gene. The sabino gene causes extensive white markings on the legs and belly (commonly seen in Shire horses) Horses which carry the sabino gene usually have white lip and chin markings. Funnily enough, Otis has a white lip and chin. Now I`m not saying he`s also got the sabino gene as his white markings are fairly conservative, but it`s a definite possibility.

It`s a complex and fascinating topic, equine genetics, so I`d be interested in reading a beginners guide to equine genetics. If there is such a thing of course!


10 thoughts on “Equine Colours

  1. firnhyde July 10, 2014 / 7:52 am

    That’s fascinating! Working at a coloured horse stud, I’ve met horses of loads of interesting colours. Some of the rarest colours were smoky black tobiano, palomino tobiano, bay overo and grulla (black dun). Plain ol’ dapple grey remains my favourite, but the piebalds are very attractive. We also had a chestnut colt at the stud who carried both rabicano and sabino: he had a slight scattering of white hairs across his hindquarters and barrel, had four stockings (the hind stockings reaching up past the stifles) and a blaze that extended over his nose and lower lip. He’s going to grow up pretty flashy.

    • therubbercurrycomb July 11, 2014 / 7:58 pm

      I do quite like the tobiano which are like a blue colour, possibly your smoky black? And palomino anything is a hit with me! 🙂

      The chestnut colt sounds lovely!

      • firnhyde July 12, 2014 / 5:11 am

        Smoky black looks deceptively like dark bay when it’s masked by pinto. The blue pintos are probably grey or roan tobiano – not very popular with breeders as they usually end up white all over in old age! But they are very striking.

  2. Susan Friedland-Smith July 10, 2014 / 4:05 pm

    Oh Otis!
    I admire your dedication to science. I have a vague memory of genetics from high school and there was something about blue eyed + brown eyed and a chart of some sort. I’m more of a words person and not so much of a math/probabilities/science person. The fact that you’re both science, words and an equestrian is impressive! 🙂

    • therubbercurrycomb July 10, 2014 / 8:10 pm

      I’m not that good at science, I can do it in laymans terms but once it gets technical I’m lost! I remember the brown and blue eye chart (brown is dominant!) I think it’s the easiest gene to describe 🙂

      Perhaps I’m just a jack of all trades 😉 glad you’re enjoying the blog though!

  3. Aline S Tempesta February 19, 2017 / 7:35 pm

    Hi! My name is Aline, I’m from Brazil, and I have a 11 month old colt called Maximillian. Still don’t know what coat color is he going to have, so I’m making some researches, and found out about the rabicano coat, and then I found your blog and this post about Otis.I was wondering if you could answer me some questions, so perhaps I would figure out if I have a rabicano or a grey colt! Thanks 🙂

    • therubbercurrycomb February 19, 2017 / 7:37 pm

      Hi, ooh exciting! Feel free to ask questions but I’m no expert on colours and genetics 🙈I’ll do my best though!

      • Aline S Tempesta February 19, 2017 / 9:03 pm

        Haha, no problems!! 🙂 well… Max was born with a gorgeous tail that has two white stripes on the outsides and a large brown stripe in the middle. As he grew older, some white hair came out on the base of his tail, just like I can see in Otis’s tail in the picture, and a few tail hairs started to grow all white too. And he has some white hair in his groins, and a few in his butt and barrel. BUT he doesn’t have ANY white hair in his neck and head. His mother is fleabitten gray and his father is bay. I know that gray is a dominant gene, right? At first I thought that he was going to be gray, but now I don’t know anything anymore, I’m so confused. Hahaha I can show you some pictures, if you want so! Do you own Otis since a baby? Can you tell me if he was already born with the white marks on the tail, or with some white hair through his body?

      • therubbercurrycomb February 19, 2017 / 10:30 pm

        I’ve had Otis since he was 2, and he’s always had the white top of his tail, and little white flecks all across his bay body. I think rabicano genes can be as subtle as just the tail or as much as they almost look Appaloosa. Have you seen the Wikipedia article on rabicano and sabino genes? They have good photos?
        Grey is dominant… but colours aren’t caused by just one gene so perhaps your boy has inherited two rabicano genes (one from each parent. Maybe his mum is heterozygous?) instead of the dominant grey gene?

      • Aline S Tempesta February 22, 2017 / 9:45 pm

        Yes, I’ve seen the article!! They have good photos, but no information about if the foal already borns with the markings, or if they get them as times goes by, like gray horses.
        I can say his father doesn’t have any rabicanos at all listed in his genealogy (as far as I can see it), but about his mother I don’t know, because I’ve never had access to her genealogy… wish I could, though!!

        Well, thank you very much anyway!! 🙂

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