Grey horses are unique because they are born dark, with either black or chestnutbase and slowly “grey out” with every shedding. All horses affected by the grey modifier grey out, no matter what color they are born.
About the Grey Modifier
Modifier that depigmentates colored hairs as the horse ages
Skin may also depigmentate which causes mottling
Greying varies between horses and breeds
First signs of greying are usually around the eyes
All gray horses grey out no matter what color they began
Different Greying Stages
Every grey horse will go through all of the below stages at some point in their life. Greying varies between horses and breeds.
Steel / Iron Greying Stage
First stage of greying process
Face tends to lighten first
Can have a bluish tint
Often mistaken for grullo
Dapple Greying Stage
Second stage of greying process
Most commonly expect when they think of grey horses
Occurs during ages of 4-12 & vary by speed of greying and age
As horses grey out they have a rosy tint to their coat
Bay Color Modifier
Perhaps one of the most well known horse colors, the bay comes in a variety of different shades and can be identified by their black points (mane, tail and legs).
A bay horse is an animal with a black base affected by the Agouti gene which controls the distribution of black hair to points and topline. This gene only affects a black base because chestnut hides the Agouti gene.
A dominant color
Common in all breeds
Red body ranging from light to dark with black points
Wild bay is a rare subtype with black legs that only extend up to pastern or fetlock
Different Bay Shades
There are a variety of different bay colors and they fall under these general categories.
This color modifier is common in all breeds is expressed by a lightening of the animals soft spots, generally the muzzle, belly, flank, elbow and eyes. This gene is also often found in mules and burros, and easily identified by a characteristic lightened muzzle.
The picture below is a fine comparison of two similar colored horses, one with the Pangare gene and one without.
Thought to be a form of natural camouflage, the sooty or smutty gene causes black hairs to grow mixed into the body coat (generally along the topline & points). This often results in dappling and in rarer cases brindle striping.
Sooty / Smutty Modifier
Can be a seasonal effect as some buckskins who display darker striping and shading along their topline during certain times of the year. Experts don’t know if this is related to the primitive striping found in duns, although buckskins who display it can be mistakenly identified as dun.
Darkens color in specific areas
Can cause dapples
Can cause individual black hairs
Generally causes a darker shade on the topline
Can darken uniformly
Also called countershading or coloring
This coloring can be found on both black & chestnut bases (that includes bays). Although darkening of the coat only has a visible affect on variations of bay & chestnut animals.
The presence of black hairs on a chestnut based animal poses a contradiction, as the ‘ee’ gene blocks production of black hairs. It is thought that the sooty gene cancels out the black pigment blocking properties of ‘ee’ animals. This is largely believed because even palominos (also affected by a creme dilution gene) can also grow black colored hairs that are not diluted by the cream gene.
Although the cause of this coloring and how it’s passed on genetically is unknown it’s passed on readily enough to be dominant to some degree.
The flaxen modifier only affects mane and tail color in chestnut based horses. This gene displays in a white to cream colored mane and tail with a reddish body coat, and does not always affect the mane and tail to the same degree.
Not much is understood about this modifier, although it is thought to be a recessive gene, and it is often mistaken for a silver dapple.