Roan Horses

What is Roan?
The roan gene ("Rn") mixes white hairs evenly throughout the base coat or the main body. True roan is caused by the "Rn" gene, which is dominant.
A horse must be a roan in order to have roan offspring.True roans usually have normally (non-roaned) colored faces and lower legs. The Roan coloring may not be apparent in the foal coat, but once the first foal coat is shed, roan is stable throughout life. ROANS do change seasonally - from obvious roan in summer to a more solid color such as bay or brown in winter - and the roaned part of the body may turn very white in late winter as shedding begins

The Rn gene has long been believed to be lethal in the homozygous state, with all RnRn embryos being resorbed very early in the pregnancy (usually before the owner knew the mare had conceived). However, recent research at the Veterinary Genetics Laboratory of the University of California, Davis, has disproven this long-held theory.

Roan itself is not lethal.
Several stallions have been identified that are homozygous for roan and have tested as such. It is not a test that is commercially available to the public, but it is possible to test for it based on a nearby gene (we don't know the gene for roan). Roan was only thought to be lethal because a paper was published in 1979 by Harold Hintz at Cornell that showed, statistically, that roan should be an embryonic lethal because of the ratios of roan-to-non-roan foals born to two roan parents. This turned out not to have a genetic basis, according to the Veterinary Genetics Laboratory of the University of California, Davis.

Roans and horses undergoing a greying process can be confused. Roan horses may have some coat variations through the seasons, but Grays continue to produce more and more white hairs as they grow older. Grays also develop white hairs over their faces and lower legs.

Another pattern that look similar to ROAN is VARNISH ROAN APPALOOSA. This pattern is caused by the Lp gene, and is unrelated to Roan.

The Difference Between ROAN and VARNISH ROAN:
TRUE ROANS:
- A Roan horse displays the full base color, with roaning added to the body coat. The "points" (mane, tail, and lower legs) and face have little or no roaning.
- The Roan pattern may not be apparent in the foal coat, but is stable through life thereafter.
- Roan changes seasonally (more white in the winter coat) but is otherwise stable throughout life.

VARNISH APPALOOSA:
- Varnish Roan usually has a whitish or grey body, with color mainly on the cheeks of the face, and around the knees.
- The Varnish Appaloosa pattern is not stable. Much like the Grey gene, the horse is born another color (usually another appaloosa pattern), and the Varnish pattern gradually overtakes it.

TERMINOLOGY: RED OR BAY ROAN? RED OR STRAWBERRY ROAN?
Genetically, the roan gene can act on any of the base colors. Roan on black is called Blue Roan; But from there it gets confusing - conventional terminology and various breed registries define the colors differently. Some say that if the horse has ANY red on it (like a black with gold muzzle from the pangare effect) it is a red roan. Some say that a red roan is Roan on a Red Base. Others call this same effect a Strawberry Roan.

Since color terminology is not standardized, you can choose whichever terms you want. It is important to understand, however, that others may be using the terms differently.

It helps to understand the genetics involved.