Solid Horses - Red & Black

In general, there are several genes working in combination which cause a

horse's appearance and colouring. However the genetic makeup of basic Black

or Red horses is remarkably simple. All horses in existance have a basic coat

colour - or pigment colour, every horse falls into the category of Black or

Red.

In the case of solid horses, the base colour is easily visually determined,

but genetic testing is useful for breeding purposes, as breeding two horses

of the same colour may not always yield foals which share that colour.

The reason for this is simple:

Black = Dominant

Red = Recessive

This means that if a horse inherits the Red pigment from one parent, and the

Black pigment from another, it's base colour will be Black and recessive

Red remains hidden in the horse's genetics.

You might wonder in which case, surely then it's simple, that mating a Black

horse to a Red will always yield a red foal? Unfortunately this is not the case,

since as mentioned before, some Black horses will carry the Red gene recessively

or 'hidden' and will pass the red pigment to approximately 50% of their

foals when bred.

-If a horse inherits a Black gene from either parent, it will appear Black.

-A Red horse only exists when both parents pass Red to the foal, and no black is present.

The Animal Genetics Red Factor test will determine if your Black-based horse carries

the recessive Red gene. We code the results as following. The Big 'E' represents

the dominant Black, and the small 'e' represents the recessive Red. Our test results

are as follows:

EE - Homozygous Black. Horse carries only the black pigment, and will pass the Black

to 100% of foals when bred, therefore this horse can not produce a Red/Chestnut foal

regardless of mate.

ee - Homozygous Red. Horse carries only the red genetics, and will pass red to all foals,

however if bred to a black mate, could still produce black foals.

Ee - Heterozygous. Horse carries both the Black and Red pigment genetics. Black is dominant

so the horse will be black, can pass either colour to foals. Can produce Red foals if

bred to another Heterozygous Black, or to a pure red.

Other relevant tests:

Agouti: The Agouti gene transforms Black horses to Bay colouring. Some very dark bays

may appear Black therefore testing is useful to determine the correct colouring. In the

case of Red horses, it has no effect on them, they can however still carry it, therefore

potentially could breed Bay foals if bred to Black mates. Please see the Agouti section

for more info.