GraycoatcolorAug06.pdf

isn’t a “color.”

Breed associations have

co-opted the term for

registration purposes,

but graying is actually

an aging process that

eliminates a horse’s

normal coat color.

When a person’s hair starts to turn

gray, we realize they are getting older.

Yet, when we think of gray in horses,

we often simply see color—he’s sorrel,

bay or gray.

But when it comes to graying,

horses aren’t that different from us.

People are born with blond, brown,

black or red hair, and, at different

rates for each of us, our hair gradually

loses its color and becomes gray, per-

haps even white. In humans, gray isn’t

a color, and this is a principle we

should also apply to horses.

“There’s the misconception that

gray is a color, and it isn’t,” said Dr.

Bonnie B. Beaver. “Gray is a white

pattern imposed on a base color.”

A veterinarian and specialist in ani-

mal behavior at Texas A&M Univer-

sity, as well as a breeder of Palominos,

Beaver co-authored the book Horse

Color with Dr. D. Phillip Sponenberg,

professor of pathology and genetics at

the Virginia-Maryland Regional Col-

lege of Veterinary Medicine.

It’s easy to label a horse a particular

color based on what we see. That’s

how breed associations initially began

registering colors, before equine ge-

netic research revealed that a gene sep-

arate from body color controls gray.

“Gray is dominant,” said Sponen-

berg, who has also written the book

Equine Color Genetics . “So gray horses

should have a gray parent.”

Horses are born with a particular

body color, and if they inherit the

dominant gray gene from their sire or

dam, they will eventually lighten to

gray. Some become gray at a very

young age, while others take years to

gray out.

“I don’t know of any way to predict

the speed with which a horse will go

gray,” said Sponenberg. “It does differ

somewhat breed to breed, implying

that genetics plays a role.”

Graying can dramatically change a

horse’s look as it ages. Five-time World

Champion HBF Iron Man, for exam-

ple, looked much darker when he was

winning at the World Show as a 3-

year-old in 1999, than he does today.

“HBF Iron Man was bay when he

was foaled,” said Celeste Fender, who

co-owns the stallion with Robin De-

grafe and who raised him from a colt.

“He had a little rim of gray around his

eye. His barn name when he was

young was “Rusty” because he was a

rusty color.”

Yet, by the time HBF Iron Man was

winning his first world championship

at age 3, he was a dark gray. Today, the

now-10-year-old stallion is a much

lighter gray, with only the black

points of his original color left on his

legs and the tips of his ears.

By Tracy Gantz

Horses are not born gray. They“gray

out” over time. For example, HBF

Iron Man was a bay foal. The only

clues to his eventual coat change

were the rims around his eyes.

Gray in Paints

Because the Paint breed developed

from the amount of white that occurs

on a horse’s body, graying can be a

challenge for Paint breeders and own-

ers. As the gray lightens a horse’s orig-

inal body coat color, it becomes

harder to distinguish between the

color and the white areas of a horse’s

body. If a horse is going to gray, it’s

important to register the animal early,

especially if it has minimal white.

“When people submit their regis-

trations early in the foal’s life, deter-

mining eligibility isn’t difficult,” said

Cindy Grier, manager of APHA’s reg-

60 u PAINT HORSE JOURNAL u AUGUST 2006

GRAY

istration department. “It’s when they

wait until the horse has grayed that

determining eligibility can be more

difficult. The contrast between a true

white marking and a gray coat color

can sometimes be difficult to differ-

entiate in photographs.”

In most horses, the skin retains the

original body color when the horse

grays, whereas white patches have no

pigment at the skin level. Because of

that, one trick that works to show the

contrast between gray and white is

hosing down the horse with water.

“Often, a trusty garden hose will

help us ‘see’ the horse’s original body

pattern,” Grier said.

Grays make up only 1.6 percent of

the total number of Paints registered,

according to Grier. But she added that

the number should probably be higher

because it doesn’t include horses that

were originally registered as their base

color without the registration being

updated when they grayed.

Paint breeders are more likely to

breed for typical Paint color patterns,

such as tobiano and overo, or perfor-

mance traits, which may be another

reason for the small amount of gray in

the breed. By contrast, breeds such as

the Lipizzaner and the Percheron are

almost all gray, while gray is also very

common in breeds like the Arabian.

Gray genes

Because the gray gene is dominant,

it is relatively easy to get a gray horse.

While the study of genes is by no

means complete, we do know that

genes occur in pairs, with each parent

giving one of the pair to its offspring.

We can designate the gene for gray as

“G” and the gene for non-gray as “g”

to indicate that gray will dominate

over non-gray. In other words, if a

horse receives a “G” from one parent

and a “g” from the other, it will gray

because the “G” is dominant and the

“g” is recessive.

When a horse receives both a dom-

inant and recessive gene, it is het-

erozygous for the trait—it has one of

each. If the horse receives two domi-

nant genes (graying would be indi-

cated by “GG”), then it is homozy-

gous dominant, whereas if it receives

A horse of a different age—not color. As is the case with all horses that go

gray, 10-year-old HBF Iron Man has appeared to develop more white hair each

year of his life. In truth, the stallion’s bay hair has simply lost its color.

PAINT HORSE JOURNAL u AUGUST 2006 u 61

GG Gg

Gg Gg

Gg gg

Gg Gg

Above, the box on the left shows that a heterozygous gray (Gg) sire and dam have a 25 percent chance of producing

a homozygous gray (GG) foal, a 50 percent chance of producing a heterozygous gray foal and a 25 percent chance of

producing a non-gray (gg) foal. On the other hand, as the box on the right indicates, having one homozygous gray par-

ent will guarantee a foal that will turn gray, even if the other parent is another color.

two recessive genes (“gg”), then it is

homozygous recessive.

If a horse is a homozygous gray

(GG), all of its offspring will be gray.

If it is homozygous recessive for the

trait (gg), then it will not be gray and

will not be able to pass gray on to its

foals. However, such a horse could get

a gray foal if bred to a horse with a

dominant gray gene (GG or Gg).

Most gray horses are heterozygous

gray (Gg). That means that they can

contribute either a dominant or reces-

sive gene for the trait. Theoretically,

two heterozygous gray horses would

produce 25 percent homozygous

grays, 50 percent heterozygous grays,

and 25 percent non-grays (homozy-

gous recessive for gray). Visually, that

would mean 75 percent gray horses.

Of course, just like a coin flip

would theoretically produce 50 per-

cent heads and 50 percent tails, but

doesn’t, breeders won’t get those exact

percentages either.

Or, as Beaver added with a laugh,

“We all know that if you breed for a

particular color, you won’t get it.”

Plus, a gray stallion’s book won’t con-

sist entirely of gray mares. Likewise, a

gray mare will probably not be bred to

a gray stallion every year. Instead, gray

horses are usually bred to horses of a

variety of colors. All of the non-grays

they are bred to will be homozygous

recessive for gray. When a heterozygous

gray is bred to a homozygous recessive

for gray, the offspring should be half

gray and half non-gray.

Beaver said that she is not aware of

a genetic test to determine whether a

gray horse is homozygous or het-

erozygous. If a horse produces even

one non-gray, then it is heterozygous

for gray. The opposite is not necessar-

ily true, however, because no matter

how many foals a horse produces,

chance—instead of genetics—could

make them all gray.

HBF Iron Man is a good example

of how a heterozygous gray stallion

Paint racehorse Aze Beduino was sired by the gray Thoroughbred Beduino. Since The Jockey Club began listing gray

and roan as one color, Paint owners have had problems predicting if their half-Thoroughbred foals will turn gray.

62 u PAINT HORSE JOURNAL u AUGUST 2006

typically reproduces. From his first 75

foals, the stallion has sired 36 grays

from books that include mares of

many colors.

When crossed three times with the

sorrel overo mare Miss Sonny Bonanza,

HBF Iron Man has sired three gray

foals, whereas when crossed four times

with the chestnut overo mare HBF Flirt

N Fancy, he has sired two grays, a bay

and a chestnut. And when bred twice

to the sorrel mare Eagley Jazzed, he has

sired a bay and a chestnut.

HBF Iron Man and the gray mare

Eternally Matched have produced

two grays, while he and the gray mare

Wicks Park have produced one buck-

skin.

Fender said that though her blood-

lines reflect the performance traits she

is looking for, she was hoping HBF

Iron Man would be gray. Likewise,

breeders who take their mares to the

stallion are also hoping that they will

get a gray foal along with the stallion’s

performance ability.

“They consider gray a bonus,”

Fender said.

“Gray doesn’t tell me anything,”

said Beaver, who in breeding Palomi-

nos is very concerned with base coat

color. “If you don’t know a gray horse

when it is young, you may not be able

to know its base color.”

Beaver cites the example of a gray

horse that has black points on his legs,

mane, tail and ears.

“People assume that the horse was

originally black,” she said. “But he

could have been bay, grullo or buck-

skin. These horses are not going to

breed like a black horse. They are going

to breed what the base coat was.”

Enter the “color” roan to confuse

things even further. Like gray, roan

isn’t genetically a color. However, in-

stead of introducing white hairs as a

horse ages, like gray does, roan sprin-

kles white hairs among the horse’s

base coat color from birth, and the

amount of white does not change

with age. Also, the roaning pattern

may not be consistent throughout the

horse’s body. It may concentrate in

such places as the hindquarters, girth,

barrel and tail dock. It is also possible

for a horse to be a gray roan.

APHA and the American Quarter

Horse Association distinguish be-

tween gray and roan. The two organi-

zations even have different colors of

roan. APHA allows owners to register

blue, red and bay roans. Yet, The

Jockey Club, which registers Thor-

oughbreds, has combined gray and

roan into one color classification to

reduce the number of corrected regis-

tration certificates. The Jockey Club

acknowledges that the two colors dif-

fer genetically, but its combination of

the two can introduce confusion

when a Thoroughbred becomes part

of a Paint or Quarter Horse pedigree.

HBF Iron Man received his gray

gene from his dam, the Thorough-

bred mare Strawberry Lane. The

Jockey Club had registered her as a

roan, an incorrect designation that

can be discovered by looking at her

pedigree and produce record. Straw-

berry Lane traces back through her

sire to the gray Thoroughbred cham-

pion Native Dancer and through her

“roan” dam to her gray second dam,

Lou-Sepha. Strawberry Lane not only

Melanoma

and

GRAY

Because the skin of gray

horses tends to have more

melanin in it than that of other

horses, gray horses can be more

prone to developing melanomas,

or small tumors on the skin.

Though they are rarely fatal,

melanomas can be unsightly and

can cause chafing, if they inter-

fere with tack.

Melanomas do not usually

occur in younger horses. They

can often be found under the

dock of the tail, around the geni-

tal area, near the ears and eyes

and in the jugular area. Most

melanomas do not cause the an-

imal any pain, and they don’t

often metastasize, as melanomas

can do in humans. Thus,

melanomas may not cause a

problem to the horse during its

normal lifespan.

Surgery and laser treatment

can be used to remove

melanomas, but veterinarians do

not always recommend this

course of action. As with any

equine health issue, you should

consult your veterinarian as to

what, if anything, should be

done in each particular case.

Determining color

Even though gray isn’t genetically a

color, when it comes to registering

horses, it is considered a color. APHA,

as do most other major breed associa-

tions, labels gray a color for registra-

tion purposes, and gray trumps all the

others. In other words, if you have a

sorrel, bay or black horse that will

eventually turn gray, it should be reg-

istered gray.

It’s still helpful to know the base

color of a gray horse, especially since

base coat color and gray are con-

trolled by two different genes. In fact,

in Equine Color Genetics , Sponenberg

writes that horses get their color from

11 genetically independent processes.

These include genes that cause white

patterns in Paints, as well as genes

that dilute such basic colors as bay

and chestnut/sorrel into colors such

as buckskin, palomino, cremello and

perlino.

Because gray acts on the base coat

as the horse ages, it is sometimes dif-

ficult to know the original base coat

color of an adult horse.

horses

produced the obviously gray HBF

Iron Man, but also the 1993 Thor-

oughbred filly Cranberry, who was

registered as a “gray/roan.”

Most of the time, the parent is con-

firmed gray and its information is up-

dated. However, if that cannot be

confirmed or the photos of the parent

show it not to be gray, then APHA

will require parentage verification.

While it may be tempting with a

possibly gray foal to wait on registra-

tion, that may not be convenient for

those who want to show a foal early.

Grier also advised registering early so

that a Paint’s white areas show up

their best, noting that it is easy to

amend a registration certificate later.

“All a member needs to do is return

the original certificate, current pho-

tographs of the horse and a note or

completed correction form requesting

the change,” Grier said. “Color

changes are done at no charge to

APHA members.”

If a horse’s base coat color is one of

the lighter, diluted colors, such as

palomino or cremello, gray can be es-

pecially difficult to determine.

“A cremello, for example, could go

gray,” said Sponenberg, “but would

still end up being a pale, pink-

skinned, blue-eyed horse.”

Mapping the gray gene and devel-

oping a test for it may eventually solve

these registration problems. Work is

being done to map more of the

equine genome, and it has been re-

ported that a team of researchers in

Sweden is working on the gray gene.

Until then, gray will continue to draw

primary attention through its dra-

matic “color.”

“A lot of people like gray horses,”

Fender said. “They really stand out in

the ring.” P

Registration difficulties

Even though APHA offers many

different categories of color, people

can still have trouble properly identi-

fying their horse at registration time.

Roans may not have enough of the

roaning pattern for easy identification,

while gray will often not show up be-

fore a horse needs to be registered.

“People who have raised a lot of

gray horses know what to look for,”

Beaver said. “A foal who will eventu-

ally turn gray may have a dustier color

around their face. But if you’re not

used to it, you won’t pick it up.”

APHA’s Grier agreed with Beaver.

She said that an ultimately gray horse

that as a foal looks sorrel or bay, for

example, will often have an unusual

hue compared to a non-gray foal of

the same base color.

Fender noted that while she could

tell that HBF Iron Man would gray as

he got older, the stallion’s first foal,

HBF Drop Your Irons, fooled them.

“Drop Your Irons was a bright

cherry red when he was born,” Fender

said. “He had no gray around his eye

or anywhere.”

Registration photographs can often

help in determining whether a horse

should be registered gray. The APHA

registration department can raise the

question with an owner if a foal’s pho-

tos indicate that it may eventually

turn gray.

Parentage also provides a clue be-

cause genetically a gray horse must

have at least one gray parent. If it does-

n’t, then usually a mistake occurred

when the parent was registered.

“We see obviously graying foals that

do not have a gray parent, but gray is

apparent in the pedigree further

back,” Grier said. “The sire or dam

obviously was registered as its base

color and never updated.”

If that happens, APHA contacts the

owner of the parent whose pedigree

suggests that’s where the gray came

from, requesting current photos and

the original registration certificate.

Gray Paints, such as the tobiano mare Chiqua Little Lena (pictured with owner

Sandy Kaplan), are growing in popularity because of their unique eye-appeal.

64 u PAINT HORSE JOURNAL u AUGUST 2006

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