 WHAT ARE THE COLOUR GENETICS OF BLUE ROAN?
It is, in effect, the ROAN gene affecting a BLACK horse. The colour genetics of BLUE ROAN are identical to that of BLACK and, to some extent, BROWN. (See BLACK and BROWN)
In the past, some horses registered as BLUE ROAN may actually have been GRULLO ROAN, since both BLUE ROAN and GRULLO ROAN have a black mane and tail, black on the lower legs, and a darker head that is usually black. Since there is no separate colour choice for GRULLO ROAN, the colour BLUE ROAN has often been chosen instead. Sometimes the DUN characteristics may not have been taken into consideration. (See GRULLO).
Just as some BLACKS and BROWNS have a PALOMINO or BUCKSKIN parent and may also carry the CREAM DILUTION inherited from one of these parents, the same is true with some BLUE ROANS. These BLUE ROANS will then have the colour genetics similar to BUCKSKINS and may produce any of the DOUBLE DILUTE foals if bred to a PALOMINO, BUCKSKIN, or parent known to carry the CREAM DILUTION.
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A BLUE ROAN has a base colour identical to BLACK and sometimes BROWN. On a BLACK horse with the ROAN gene added, white hair is mixed in with the base coat, leaving the lower legs, the mane and tail, and the head typically unaffected. In extreme cases, however, a ROAN may have a concentration of hair above the eyes (but not located directly at the eyes nor immediately around them) appearing as though the horse had white eyebrows The concentration may also be found at the polls or base of the ears (but nowhere else on the ears). Concentrations may be found on the jaws as an extension of the white hair already concentrated on the neck. In its least expression, the BLUE ROAN may have ROAN hair localized over the back and croup area, giving the horse the appearance of being slightly dusted with snow. These are sometimes called 'minimally expressed' ROANS.
In the case where the ROAN gene affects a BROWN horse, the overall appearance of the horse is still due to white hairs being mixed with very dark brown and black hair over the body coat. Also, the overall colour of the head of the horse remains dark brown or a mixture of black and brown hair. There are some horses registered as BLUE ROAN where the head may have red or tan mixed in with the darker hair. However, the mane, tail, and lower legs will be true black. ROAN on a BROWN horse (genetically a BLUE ROAN) has often been confused with ROAN on a CHESTNUT horse (genetically a RED ROAN).
A BLACK or BROWN may have white hair scattered throughout the body or have white hair concentrated in specific areas. These areas are usually the flanks, between the fore legs, the root of the tail and sometimes over the barrel, usually in vertical patterns directly over each rib. It is most often confused with ROAN but is neither the result of the ROAN nor GRAY genes. This distinct pattern of white is sometimes called rabicano (pronounced rab ih CON oh), a word of Spanish origin meaning "brush tail," referring to the bands of white hair at the root of the tail. It is also referred to sometimes as "ticking." One way to determine the difference between the 'classic' BLUE ROAN and a BLACK or BROWN with white hair due to the rabicano or ticking trait is to notice the colour of hair once the 'roan' areas have been scraped or robbed off. On a 'classic' ROAN, the ROAN hair does not grow back once scraped off-only the base colour will grow back, in this case,
black or brown. On the rabicano affected horse, the hair that is scraped off will usually grow back solid white, the same that would happen if the horse was a solid BLACK or BROWN. |
