A Genetically Sound Breeding Program
By Dr. Clinton G. Depew
University of Louisiana
The goal of every horses producer is to produce champions. Although there are
many environmental factors such as nutrition, health care, training and injuries, that
have an effect on the horse's eventual capability, from a genetic standpoint the old
adage of "breeding the best to the best and hoping for the best", is still the simplest and
most accurate statement of a good breeding program.
The most important factor affecting the type of breeding program to be used in
the horse business is heritability. Heritability simple defined means the percent of a
horse's genetic potential that can be passed to the next generation. When heritability is
high, simply mating the best stallions and mares available should produce the best
offspring. Inbreeding, linebreeding and special nicks only play a part when heritability is
low and hybrid vigor is utilized to produce a colt which is better than either its sire or
dam.
In horses, heritability is quite high in most of the traits of economic importance.
Table 2 shows that speed, conformation, athletic ability and intelligence are generally in
excess of 50% heritability. Therefore, horseman should simply select those horses
which are superior in the desired traits without regard for a particular line of breeding or
possible nick. The popularity of crossing certain bloodlines and certain great nick in
history can more accurately be explained genetically as simply the result of crossing two
outstanding individuals.
Because heritability is high in horses, a horse's actual physical characteristics or
capabilities are a good reflection of his genetic capability. Therefore, with high
heritability in horses, low quality horses regardless of their breeding or line of breeding
will never produce good colts, with the exception of an occasional fluke. On the other
hand, simple selection of high quality stallions and mares will maximize a producer's
potential of producing champions.
Progressive breeders should start with the best stallion and mares he can afford,
cull any mares which don't produce high quality colts, and keep the best quality colts for
his next generation.
Trait
Speed
Conformation
Height
Weight
Length and Stride
Intelligence
Fertility
Table 2 Heritability estimates of Horses
Heritability %
67%
41%
61%
57%
68%
53%
10%
Elm Tree Farm is proud to be standing Extra Gear TB and Symbolic Times TB. Each is
the product of selective breeding of outstanding individuals to outstanding individuals as the bloodlines show. Their physical characteristics are testimony to Dr. Depew's
views on breeding. We would encourage you to breed for excellence and pray for color for an excellent foal will always return your investment. We do not promote color as the
ultimate goal. Look at each individual when making your breeding decisions - then look
to the pedigree and the consistency of the families to produce quality.