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Inbreeding ... from "Bloodlines N Pedigrees"
Chapter from the forthcoming book, "Bloodlines N
Pedigrees"
by Larry Thornton
(c) Copyright 2004, Larry Thornton. All rights reserved.
Reprint permission must be in writing.
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Pedigrees"
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The general definition of a breed is "a group of
animals with common ancestors and distinct characteristics that are passed on generation
after generation." This ability to pass these characteristics on generation after
generation comes through inbreeding.
Inbreeding is defined as "the mating of animals more
closely related than the average of the population." This includes sire to daughter
matings; son to mother matings, full brother to full sister matings and half brother to
half sister matings.
The early development of the "pure breeds," as we
know them today, provides us with some insight into the desirable effects of inbreeding.
England's Robert Bakewell is considered the originator of modern breed development.
Bakewell believed in the philosophy of "breed the best
to the best to get the best." So he assembled the "best" animals he could
find and then set out to develop the "type" of animal he wanted. He closed his
herd and that meant he had to retain only the genetically superior individuals to obtain
the desired "type." This meant that he had to inbreed to set the type.
Bakewell's success led others to develop "breeds" that bred true or
"pure" for certain characteristics when mated within the herd.
The Celebrated American Quarter Running Horse of Colonial
America experienced a similar development through inbreeding to *Janus. Quarter horse
historian, Helen Michaelis assembled a great deal of colonial history on the quarter
horse. She reported in the "Sons Of Janus" (THE QUARTER HORSE JOURNAL, April
1951) that colonial breeders bred their mares to winners and the sires of winners.
*Janus was one of the successful sires of colonial winners.
Michaelis tells us, "After the arrival of Janus it was within the Janus family that
most of the winners were found. Some of the Janus-bred horses had so many crosses to
*Janus that modern writers questioned their pedigrees."
Michaelis went on to explain that *Janus stood at stud 28
years and that the Colonists believed in *Janus blood. She credits this Colonial attitude
to the philosophy of, "if one Janus cross was good-several should be better."
Michaelis' report tells us that the outcome of this
inbreeding, "resulted in a horse that could not run a full quarter mile..
Concentrated *Janus blood may have shortened the distance of the Colonial quarter horse
but it gave him a tremendous burst of early speed and uniformity of conformation."
Thus the foundation of the colonial quarter running horse came about through inbreeding to
*Janus. The colonial breeders had unknowingly set the "type" of animal known
today as the quarter horse experiencing desirable and undesirable results through the
practice of inbreeding.
Bakewell and the early colonists were unable to use the
genetic knowledge available to modern breeders. Bakewell's idea was to introduce and keep
the best genetics in his herd by selection. Through proper selection, he retained the
desired animals, making his herd "homozygous" for the desired traits.
Homozygosity is the basis for breeds passing on the same traits generation after
generation.
The genetic condition of homozygosity is best defined
through a short discussion of basic genetics. The horse's genetic makeup is contained on
64 chromosomes. The genes are located on the 64 chromosomes. The genes are strands of
deoxyribonucleic acid (DNA). The DNA is the code to tell proteins how to form. Thus the
genes carry the genetic material that gives the animal his physical characteristics. The
animal's physical characteristics are his phenotype or what he looks like. His genetic
makeup is known as his genotype.
The 64 chromosomes (32 pairs) come together when the sire
and dam are mated. The sire provides 32 chromosomes and the dam provides the other 32.
The gene's location is fixed on the chromosomes and
combines with another gene at that location when the embryo is formed. The two genes are
called alleles. When the alleles are identical in their code, they are homozygous. If they
are different they are said to be heterozygous.
The homozygous state is seen in such traits as the white
faces of Hereford cattle. The Hereford breeds true for this trait. Even in crossbreeding
with Angus cattle, the white face is expressed because the Hereford passes only that trait
on and it is dominant in nature. (The white face masks the black face of the Angus.)
The grey gene for horses is similar. If all the foals of a
grey stallion turn out to be grey in color, that means that he is probably homozygous for
the grey gene and that gene masks all other colors when passed on by the homozygous grey
parent.
Genes that mask their alleles are said to be dominant.
Geneticists tell us dominant genes are important to breeders because they are usually the
desirable genes. The genes masked by dominant genes are said to be recessive. Recessive
genes affect inbreeding in several important ways.
Many of the undesirable genes are recessive in nature. When
closely related individuals that carry undesirable recessive genes are mated, the chance
of exposing the undesirable genes increases. (Remember that the recessive gene can only be
expressed in the homozygous state and our goal in inbreeding is to make the offspring
homozygous for the traits we are selecting for in our breeding program.)
In the beef cattle industry, a bull is often put on a
genetic soundness test to determine if he is a carrier of genetic defects. He will be bred
back to his daughters and if the genetic defect shows up in any of the offspring, he is
then proven to be a carrier of that undesirable gene.
Many of the recessive genes are what geneticists call
"lethal genes." The expression of recessive homozygous lethal genes causes the
death of the foal at some stage of development - either before birth or shortly after
birth. Thus through natural selection the lethal homozygous recessive eliminates itself
and the breeder ends up without a foal.
The recessive gene can be carried for years through the
heterozygous individual. The homozygous recessive is expressed when two carriers are mated
with each parent contributing the recessive gene, making the offspring homozygous for the
undesirable trait. Thus the chance of the recessive being exposed is increased by
inbreeding to carriers of the undesirable gene.
Another undesirable aspect of inbreeding is a loss in vigor
of the offspring produced. This is another by-product of recessive genes. Areas that can
be affected by inbreeding are lower reproductive efficiency, poor disease
resistance and
animals that lack size.
On successfully inbred individuals the increased
homozygosity leads to prepotency. Prepotency is the ability of an animal to stamp his/her
foals with desirable characteristics, making the foals uniform in such traits as color,
markings and conformation.
The positive goal of inbreeding is to increase homozygosity
of the desirable traits, making the breeding horse prepotent. The legendary sire, Leo, was
an inbred stallion that proved to be one of the great prepotent sires and an excellent
example of what we are talking about with inbreeding.
Leo is an example of the half brother to half sister
mating. Leo was sired by Joe Reed II, by Joe Reed P-3. He was out of Little Fanny, by Joe
Reed P-3. Thus Leo was 2 X 2 inbred to Joe Reed P-3. This is a percent of blood of 50%.
This tells us that Leo could have carried as many Joe Reed genes as an own son would
carry. The percent of blood is only an estimate and we should use it as an estimate only.
The dam's of Joe Reed II and Little Fanny provided Leo with
unrelated outcross blood. Joe Reed II was out of Nellene by the thoroughbred Fleeting
Time. Nellene was out of Little Red Nell, a quarter mare by Brown Billy and out of Red
Nell by Texas Chief.
The sire of Fleeting Time was, High Time, who was inbred to
Domino, the great speed sire. High Time is by Ultimus by Commando by Domino. Ultimus is
out of Running Stream by Domino. High Time's dam is Noonday by Domino. Contrary to what
one might expect, Leo is not inbred or linebred to Domino, because no Domino blood shows
up anywhere else in Leo's pedigree. At least as far as his known pedigree is concerned.
Leo was a successful inbred performer whose performance
record is not complete. He is "officially" credited with winning 20 of 22 races
during his time at Pawhuska, Oklahoma. The rest of his race record in Texas is lost and
not a part of his official race record. He started his race career in Texas.
Leo developed into a sire known for his prepotency. Leo's
owner, Bud Warren, stated in a 1984 interview, that Leo was "a combination of genes
that clicked." Warren would breed any mare the owner wanted bred, because "the
mare's owner knew what he wanted" and they felt Leo would give them that foal.
Leo was versatile in his contribution to the breed. He was
the sire of 211 race Register of Merit. His race ROM include the Champions Miss Meyers,
the World Champion in 1953; Mona Leta, 1953 Champion Quarter Running Three Year Old Filly;
Bobbie Leo 1954 Champion Quarter Running Two Year Old Filly and Palleo Pete, 1954 Champion
Quarter Running Stallion and 1954 Champion Two Year Old Colt.
Leo was just as successful as a sire in the show arena as
he was on the race track. He was the sire of 33 Register Of Merit show horses, 24 AQHA
Champions and 1 Supreme Champion. His top show horses include Okie Leo, Superior Reining;
Holey Sox, Superior Cutting and NCHA Bronze Award winner; Leo Bingo, Superior Cutting
Horse and Leob, 1958 AQHA High Point Halter Gelding. The Supreme Champion was Leo Maudie.
Leo's legacy is as a broodmare sire. He is the leading
maternal grandsire of AQHA Champions with 58. His daughters are the dams of 7 AQHA Supreme
Champions. The Supreme Champions are Kid Meyers, Fairbars, Milk River, Goodbye Sam, Sugar
Rocket, Jet Threat and Goldstream Guard. His daughters produced 749 Register of Merit
runners as well.
Leo was a good cross on a variety of bloodlines. These
lines would include Oklahoma Star, Joe Hancock, King P-234 and Three Bars. When crossed
back on the Joe Reed line, he sired a couple of pretty good horses in Robin Reed and Leo
Gann.
Robin Reed was out of Sue Reed. Sue Reed was sired by Joe
Reed P-3. Robin Reed was 3 X 3 X 2 inbred to Joe Reed. This is a percent of blood of 50%.
Robin Reed was an AAA runner on the track. He is the sire of She Kitty, the 1962 AQHA
Co-Champion Quarter Running Three Year Old Filly and her full brother Old Tom Cat, an AAA
rated AQHA Champion.
Leo Gann was out of Chilly Nite by Joe Peed P-3. Thus he
was 3 X 3 X 2 inbred to Joe Reed with that same percent of blood. Leo Gann's Register of
Merit runners include Lady Gann, Leo C Inman, Leo Barb and Pita Gann. His ROM arena colts
include Chico Gann, an NCHA Top Ten finisher in open cutting.
King P-234 is considered by many to be a
"cornerstone" in the foundation of the quarter horse breed. King was linebred
but not inbred. He was bred back to many of his own daughters and granddaughters. This
practice lead to two significant contributions to the breed with the stallions King Glo
and Squaw King.
King Glo was an AQHA Champion and Grand Champion halter
horse. He was out of Hyglo. Hyglo was sired by Hygro, a thoroughbred. Hyglo's dam was
Jetty H by King P-234. This made King Glo 1 X 3 inbred to King P-234. This is a percent of
blood of 62.5%. Theory tells us that King Glo carried more King genes than a son or
daughter would carry.
King Glo was the sire of the winners of three of the first
four NCHA Futurities. They were Money's Glo, Chickasha Glo and Chickasha Dan. Glo Doc by
King Glo was fifth in the 1964 NCHA Futurity. This gave King Glo a finalist in each of the
first four NCHA Futurities with three winners.
Squaw King was a son of King and out of a daughter of King
named Squaw H. Squaw H was an AAA running mare. This makes Squaw King 1 X 2 inbred to King
P-254. This is a percent of blood of 75%.
Squaw King was the sire of Squaw Leo. Squaw Leo was the
sire of Be Aech Enterprise. Be Aech Enterprise was a top reining horse that has become a
great reining horse sire. His foals made him the second leading sire of reining horse
money winners in 1992. The leading Be Aech Enterprise money winner in 1992 was B H Toy
Boy, winner of over $40,000.
King Fritz was another top sire that was inbred to King
P-234. He was sired by Power Command, a son of King P-234 and out of Poco Jane, a
granddaughter of King. King Fritz was 2 X 3 inbred to King P-254. This is a percent of
blood of 37.5%.
King Fritz was an AQHA Champion with 14 halter points, 13
western pleasure points, ½ point in working cow horse, 7 reining points and 3 western
riding points. He was an NCHA money earner.
King Fritz became one of the great reined cow horse sires
on the west coast. His foals read like a Who's Who in the reined cowhorse industry. They
include the famous Shirley Chex, Bueno Chex, Mitzi Chex, Moon Chex and Karen Chex.
Power Command, the sire of King Fritz was out a very
interesting mare. His dam was Crickett McCue. Crickett McCue was sired Barney McCue by
Jack McCue. The dam of Barney McCue was Bird McCue by Jack McCue.
The dam of Crickett McCue was Fanny McCue by Jack McCue.
The dam of Fanny McCue was Bell by Jack McCue. This makes Crickett McCue 2 X 3 X 2 X 3
inbred to Jack McCue. This is a percent of blood of 75%.
Crickett McCue and her dam Fanny McCue were a good cross on
King P-234. Crickett McCue was the dam of Power Command, an AQHA Champion and King
Command. King Command was the sire of such noted horses as Dun Commander, Hesa Commander
and Hat Band.
Fanny McCue was the dam of King Black and Cage's Cattle
King. King Black was the sire of such ROM as Diana Bee, Flaxy Black, Jacky Black and Kelly
Diane. Cage's Cattle King was the sire of several ROM and AQHA Champions. His AQHA
Champions include No Scotch and Supreme Model.
We have determined that we can use inbreeding to develop a
breed. Once the breed is founded, we can develop distinct families or lines of horses
within the breed by inbreeding to the desired line of horses.
Crickett McCue was an inbred mare from the Peter McCue
family. They linecrossed Cricket McCue with King to get horses like Power Command. The
mating between lines is called a linecross.
Thus a linecross is the mating of individuals from
unrelated lines within the breed. These linescrosses are used to get hybrid vigor in the
foal. Maximum hybrid vigor is attained by mating two inbred individual that are not
related within the first four or five generations.
Hybrid Vigor is the phenomenon where the foal produced is
superior to the sire and dam. We get hybrid vigor from genetic diversity. As we learned
earlier, we inbreed to get homozygosity and we outcross or crossbreed to get
heterozygosity, which is the basis of hybrid vigor
The 1988 AQHA World Show Super Horse One For The Record
serves as an example. One For the Record earned over 2,517 AQHA points in open, amateur
and youth working events. She has 22 AQHA World Championship Show Top Tens, 17 AQHA High
Point Performance titles. Her World titles include the Senior Hunter Under Saddle titles
in 1985-87-88; World Pleasure Driving in 1989, Senior Working Hunter in 1985 and the AJQHA
World title in Working Hunter.
One For The Record provides us with an example of more than
just a linecross. She is a cross between breeds (the quarter horse and the thoroughbred).
The sire of One For The Record is Swift Solo, a
thoroughbred that has crossed well with the quarter horse. His foals include Ima Sweet
Solo, 1978 AQHA High Point Western Pleasure Horse and Sting 0 Gold, 1982 AQHA High Point
Western Pleasure Horse.
The dam of One For The Record is Record Breaker 4. Record
Breaker 4 is sired by Breaker Hancock by Buck Hancock. The dam of Record Breaker 4 is
Roxana 4 Hancock by Buck Hancock. This makes Record Breaker 4 inbred to Buck Hancock with
a 2 X 2 breeding pattern and a percent of blood of 50%.
Buck Hancock was sired by Joe Hancock by John Wilkens. John
Wilkins was sired by Peter McCue. The dam of Buck Hancock was Triangle Lady 40 by Red
Buck. Red Buck was sired by Buck Thomas, a son of Peter McCue.
The Joe Hancock blood in Record Breaker 4 doesn't end with
Buck Hancock. The dam of Roxana 4 Hancock was Hanna Jo. The dam of Hanna Jo was Anne Jo by
Joe Hancock. This makes Record Breaker 4 linebred to Joe Hancock with a breeding pattern
of 3 X 3 X 4. Thus Record Breaker 4 was an outcross on the thoroughbred blood of Swift
Solo.
Record Breaker 4 has been a good producing mare. She is the
dam of 6 foals with 4 of them performers. Her other foals include Hit Record with 157
performance points in Youth, Amateur and Open divisions. Hit Record is a full brother to
One For The Record.
We don't have to always outcross with our inbred animals.
We can use them in a linebreeding program. Of course we linebreed to keep a close
relationship to some outstanding individual without some of the risk of inbreeding. We
don't have the space to delve into linebreeding in this look at inbreeding, but here is an
example of what we are talking about.
Nevada Made has been another top show horse whose dam is
intensely inbred. His pedigree indicates a linebreeding pattern to Joe Reed II. But his
dam is inbred to a son of Joe Reed II.
This 1976 brown gelding was the 1990 AQHA World
Championships Amateur Super Horse. This great show horse has earned 28 Hunter Hack points;
25 trail points; 10 pleasure driving points; 3.5 western riding points; 52 amateur trail
points; 45.5 amateur western horsemanship points; 41 hunt seat points; 34 hunter under
saddle points; 19 amateur western riding points; 5.5 amateur western pleasure points; 5
pleasure driving points and 4.5 working hunter points.
The Nevada Made world titles include the 1990 Amateur Hunt
Seat World Championship and the Western Horsemanship title. He was the 1989 Reserve World
Champion Amateur Hunt Seat Equitation winner and the 1990 Reserve World Champion in
Amateur Working Hunter and Trail Horse.
The sire of Nevada Made was Poco Leo Bar, a grandson of
Leo. His dam was Handy Bar by Three Bars.
The dam of Nevada Made was Orovada Maid by Beau Joe. The
dam of Orovada Maid was Sorrel Sheila by Beau Joe. This makes Orovada Maid 2 X 2 inbred to
Beau Joe. This is a percent of blood of 50%.
Beau Joe was a son of Joe Reed II. Joe Reed II was the sire
of Leo. Leo was the grandsire of Poco Leo Bar, the sire of Nevada Made. This makes Nevada
Made 4 X 3 X 4 linebred to Joe Reed II. This is a percent of blood of 25%.
The Poco Leo Bar X Orovada Made cross has been a good one.
Beau Joe Leo Bar is a full brother to Nevada Made. He has earned has earned over 700 AQHA
points in the open amateur and youth divisions. Nevada Maiden is a full sister to these
two good performers and she has 21 halter points and 11 performance points.
One For The Record and Nevada Made give us two examples of
using an inbred parent in a pedigree. One For The Record gives us an inbred
parent outcrossed with another line or in this case breed. Nevada Made gives us an example of
using an inbred parent in a linebreeding pattern.
The benefits of inbreeding are often overshadowed by the
undesirable effects of inbreeding. The breeder must know where these undesirable affects
come from and how they are expressed. The breeder must be conscious of the fact that not
all animals are genetically sound for inbreeding. They may carry hidden recessive's or
lack the quality genes they need to be successful in an inbreeding program. Thus selection
of genetically superior breeding animals becomes extremely important to the success of
inbreeding. ~End
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