Skip to main content

Due to decreasing use over the years, I have decided to disable the forum functionality of the site.

Forums will still be available to view but new posts are no longer allowed.

Maximum/minimum tobiano pattern

My tobiano mare has had 2 foals by solid coloured stallions. The mare is 55/45 black/ white. One foal is 80% colour, 20% white. The other foal is 15% colour/ 85% white. I believe the expression of the tobiano gene is governed by modifying genes. The tobiano coat pattern can only have come from the mare in this case, and I am very surprised at the difference in the foals - I expected theem to be roughly similar :-? . Does anyone know how the modifiers work? Can they be contributed by the plain, non-tobiano parent? Also, does anyone know how the coat pattern is affected by environmental factors and what these might be? Thank you in advance.

CMhorses Tue, 06/26/2012 - 17:50

really need pictures for one, the foals could have more than just tobiano and that can change how much white they have; it seems like the coat could greately be affected as when looking at clones, they all have different white markings of different sizes , suggesting that white placement and amount are somewhat influenced by enviornment, now i could see a developing foal with less nutrients having more white than a foal with more because it takes certain elements to make pigment producing cells, but this is also determined by genetics, so crossing with a "solid" there is a chance your foal inherits a lot of "produce more pigment" genes and thus has less white, or in the case of your more white foal he got more of the " produce less pigment" genes from mom and dad

Monsterpony Tue, 06/26/2012 - 18:21

Second the pictures. The sires may be "solid" or just minimally marked. Either sire could contribute more or less white suppression factors, which would make a big difference in color as well as other white patterns besides tobiano. The 80:20 foal sounds like it probably has another pattern going on in the mix.

CMhorses Wed, 06/27/2012 - 01:58

well your mare is splash and/or sabino as well as tobiano, and we already know that completely solid horses can have splash or sabino

Threnody Wed, 06/27/2012 - 11:18

By having face white your mare has more than just tobiano. As do her foals. I also agree with her likely having a splash and sabino combination.