National Quarter Horse Registry ~ Since 1956


Genetic Formula: E, A, CC, dd, gg, ww, toto

Description: Bay horses are the result of the Agouti gene restricting black to the points and allowing red to show on the body.

Bays vary from light reddish or copper to dark brown, and mahogany on their bodies. They will almost always have black legs, muzzle, ear tips, mane and tail (called the points).

Some like the wild bay can have less black on the points than others. We have found this to be typical of bays with a dun or mealy factor in their line.

Some Bays may appear Black or dark Brown although most the time they will still retain the telltale gold on their muzzle and underside of their flanks. Most people grow up believing a Black colored body means a Black horse even with a gold muzzle. Due to the research work on genetics by several universities, we have come to understand that these horses are actually Bays genetically. One big problem these findings caused is how does a breeder look back at their horse's pedigree and know which of his horse's ancestors that were registered Black or Brown are in fact Bays?

The two best ways to know for sure are:

1. Have a genetic test for the Agouti gene done. The University of California Davis has an Agouti test available for the public.

2. Keep a record of offspring produced by the horse. Two true black horses cannot produce a bay, because they do not carry the agouti factor. See also the Dun, Cream, and Champagne for more on modified Bays

Markings* on Bay Base  

Black + Agouti + Tobiano (paint) 

Paint/Pinto (Tobiano)

   Blanket (Appy)  


Dilutes/Modifiers/Sooty* on Bay Base

Black + Agouti + Sooty  


Black + Agouti + Dun 


Black + Agouti + Silver Dapple (Silver Dapple)

Silver Dapple

Black + Agouti + Single Creme (Buckskin)  

Single Creme

Black + Agouti + Single Cream (Buttermilk Buckskin)


Black + Agouti + Roan 


 Black + Agouti + Double Cream (Perlino) 

Double creme

 Foal Coat SHADES*


*There are many, many more varieties


To read more technical color descriptions please visit UC Davis