The Wagon Wheel Ranch breeding program is primarily designed
to concentrate the blood of specific legendary sires, i.e.
King P-234, Joe Hancock, Red Man, Buck Hancock, Blue
Valentine, Two Eyed Jack, Leo, Bert, Mr San
Peppy; Three Bars, TB; and Top Deck, TB. To accomplish the
above, we breed King bred stallions to King bred mares; Joe
Hancock bred stallions to Joe Hancock mares, etc. This
inbreeding allows us to hold, and in some cases, to increase
the percentage of this blood carried by foals produced from
these breedings. When horses are inbred, their progeny have
one or more matched pairs of chromosomes, out of the
thirty-two (32) pairs which all horses have. The
significance of one or more matched pairs of chromosomes in
a breeding horse is that each chromosome carries hundreds of
genes. Genes carry the elements by which hereditary
characters are transmitted from parent to progeny.
Theoretically, each mature reproductive cell carries a gene
for every inheritable characteristic (the progeny receives a
set of genes from each of its parents). Therefore, when a
breeding horse has even one pair of chromosomes matched, the
consistency of that type produced in its foals increases,
notably! As the number of matched pairs of chromosomes in a
breeding horse increases, so does the uniformity of foals
produced! Practically speaking, I have found that twelve
(12) matched pairs of chromosomes is the maximum attainable
(the foals produced by the very few horses which have twelve
matched pairs of chromosomes are "rubber stamp" like in
their uniformity).
The number of matched pairs (or lack of any) is referred to
as homozygosity, and is abbreviated HZ in our horse
descriptions. The higher the HZ is, the more likely the
horse noted will be able to reproduce itself (and the
characteristics of the legendary sire to which the horse is
inbred). Ordinarily, as HZ increases, the other trait which
we watch, Hybrid Vigor, declines. Hybrid Vigor, abbreviated
HV in our horse descriptions, is the extra vitality
exhibited in a horse when no defective genes are expressed
(the horse's defective genes, which most horses carry, are
present in the reproductive cells, but do not exhibit their
presence in any observable physical traits of the horse)
allowing an individual to exhibit more size, bone, muscling,
speed, etc. than either of the parents exhibit. Ed Heimann,
when doing genetic research at the University of Missouri,
figured the average HV in running bred quarter horses at a
negative 1.2% to a positive 1.75% (however, he took only the
top 65% of running quarter horses, of that era, into
consideration; thus automatically raising the average
figures). Maximum HV is attained by breeding intensely
inbred horses of one family to intensely inbred horses of
another family, i.e. King P-234 to Leo, etc. We have found
that a positive 34% HV is the highest which we can produce
with our breeding herd.
Excellent mothering ability is one of the traits expressed
by mares carrying above average HV. Performance
potential/athletic ability is another resulting trait and is
the primary goal in our breeding the true two way hybrid
(progeny of two parents which are inbred to different
families). Although true two way hybrids rarely have matched
pairs of chromosomes, they usually will produce uniformity
in their foals more consistently than other horses which
have no matched pairs of chromosomes, and whose parents had
no matched pairs of chromosomes (known as "shotgun" bred
horses). The reason that they will do so is probably because
both of their parents are inbred, thus narrowing the
diversity of their ancestors genes, compared to the
"shotgun" bred horse's wider diversity of ancestors.
The inbreeding program which we pursue, and others now and
earlier have or are pursuing, is more hazardous (and thus
more expensive) than line breeding (a less intense form of
inbreeding, which doesn't allow for longer term
concentration of blood), breeding the "best" to the "best"
(as practiced by the late dean of early quarter horse
breeders, Ott Adams of Alice, Texas) or the majority who run
here, there, and yonder with their "shotgun" bred mares to
this or that popular stallion who may or may not be
genetically equipped to produce foals like himself on a
consistent basis. The reason for the more hazardous nature
of inbreeding is, at the same time, the reason for
practicing it in the first place! The reason being that
inbreeding concentrates blood (the gene pool), which can be
good when no defective genes (which are concentrated along
with the desirable genes) are expressed in the horse
resulting from inbreeding. However, inbreeding (in our
experience) invariably results in a higher percentage of the
resulting foals physically expressing conformational, and/or
mental defects, which are such that these individuals must
be culled from the breeding program, at the least; and
euthanized, at the worst. (Therefore, breeders, who cannot
stand such financial pressure should not practice
inbreeding, for the most part). Those who do practice
inbreeding usually come to a point in their program where
they must outcross their inbred horses with horses from
another family (usually, but not always, inbred themselves).
We, for the most part, are constantly out crossing our
inbred horses to produce true two way, and sometimes three
way, hybrids with excellent performance potential.
Through experience, we found that when an inbred female has
as many as eight or nine matched pairs of chromosomes
(produced by breeding fathers to daughters or sons to
mothers) she will tend to abandon her first foal at birth
and/or be a very poor mother with below average milk
production. To help this situation, we have learned to breed
such inbred females to an inbred stallion of another family
for her first foal. This technique produces a foal which is
a true two way hybrid carrying so much hybrid vigor that it
can persevere in the face of its dam's poor mothering
ability, and eventually (usually with some creep feeding)
attain normal size, weight, etc. Subsequently, the inbred
mare can be bred to inbred stallions of her own family, due
to her increasing maturity.
Another "problem" with inbreeding is, sometimes, a loss of
size and bone. We say, sometimes, because there is usually a
way to avoid loss of size and bone (and to avoid increasing
percentages of defects in foals produced). That way, in our
experience, is to strive to breed "genetic super horses"
(horses with both above average homozygosity, and above
average hybrid vigor). To accomplish this, one must breed
inbred horses of the same family to a member of the opposite
sex, which goes back to the blood being concentrated through
as many different paths as possible. For instance, breed an
inbred King stallion which goes back to King P-234 through
Poco Bueno, Roper Boy and Red Bud L to an inbred King mare
who goes back to King P-234 through Bimbo Hank, and King
Hankins. This procedure usually results in a superior foal,
which is still carrying a very high percentage of King
blood, yet not physically showing any defective genes (which
it may be carrying in its reproductive cells).
Inbreeding is a dirty word in the vocabulary of many horse
breeders (due to a lack of knowledge, and/or listening to
those who have no more knowledge of genetics than
themselves). However, a study of the pedigrees of many great
horses will reveal their inbreeding. Some of the great horse
breeders had formal training in genetics (those in charge of
the Robert Kleberg, Jr. era of quarter and thoroughbred
breeding at the famed King Ranch, for example), but many of
them learned to inbreed through experience, and acute powers
of observation (the Hankins brothers, Jess, Lowell and J.
O.; Guy Ray Rutland, Walter Merrick and Hank Weiscamp, for
examples). A study of the pedigrees of the horses bred by
these men, and others, quickly reveals careful inbreeding
which resulted in the Peter McCues, Old Sorrels, King
P-234s, Leos, Easy Jets, Skipper Ws and other legendary
sires.
