First Method of Selective Breeding
By Loren Bolinger, June 16-17,2006, Thursday, August 03, 2006
Matching mating partners by
their anatomical proportions preceded pedigree matching as a primary
selective breeding method for improvement.
Judging individuals by their
physiological structure: conformation, symmetry, or form, then breeding
those individuals that seem most physically compatible became the first
method of selective breeding domesticated livestock. These basic
agrarian methodologies then became the starting point for the early
English founder breeders.
Selectively breeding
individuals by their visual compatibility or conformation is the basis
of phenotypic matching [selection based on anatomical proportions,
judgement of conformation, or perceived biomechanical efficiency]. It
preceded another method of selective breeding in which mates were
chosen by their relationships, ancestry, lineages, or family trees.
“Shape
is the principle point to have regard to in order to amend faults of
sire or dam; and almost every person who likes a horse, and has any
experience, knows what good shapes are. The grand secret is to know
when they are properly put together, and to discover where the screw is
loose in the machinery which renders the whole useless.”
- The Book of the
Horse, Samuel Sidney, (circa 1875), Cassell, Petter, Galpin & Co.,
London, Paris, & New York, page 262.
Anatomical selection had to
be the first selection method practiced by breeders, since at the time
of the early English founder breeders, ancestry and parentage were
often problematic issues. The founder breeders in their passion for the
new sport of horse racing began their attempt to create a new breed of
horse - the Thoroughbred racehorse with this method. At the time, the
newly imported, Oriental founder stallions' parentage was usually
unknown. The earliest native English and/or Irish Hobbye mares often
had dubious, incomplete, or unknown parentage. The most successful form
of breeding selection was based on the test of racing - attaining the
winning post - combined with keen assessment and judgement of
conformation. Finally, those individuals failing to measure up were
usually culled. These became the biological tools that drove the early
development of the Thoroughbred.
Among agriculturalist of
these early times [pre-industrial England], the anatomical proportions
of all farm animals were intently judged; farming success depended on
accurate assessment of the qualities of all stock. Intense evaluating
by all agriculturalists of all livestock is a farming practice that
goes back before the Roman Empire and even earlier. Indeed even every
human’s survival was highly depended on the qualities, yields,
and efficiency of all manner of husbandry. It's natural that the
physical proportions of the horses of this new sport of racing would be
judged just as intently for their suitability to race and win.
Ranking the conformation of
breeding stock, judging, measuring, and recording physical proportions,
evaluating compatibility of form between potential parents was an all
consuming preoccupation in an agrarian society. Almost all
agriculturalists of the [pre-industrial age] 13th century onward were
quite familiar with judging the physical appearance of domesticated
plants and animals: "beauty of form" [Wood, Orel, page 76]. Livestock
judging persists even today not only in farms and ranches, but also in
the state and county fairs, 4-H Clubs and Future Farmers of America.
Developing a keen eye for conformation and other outward manifestations
of phenotype was a very important attribute in an agrarian society. It
was only natural that animals judged more attractive and deviated less
from a mutually accepted [agreed] standard would be considered more
valuable and more desirable.
[Wood, Orel, page 76, quoted] Marshall 1790 [The Rural Economy of the Midland Counties] wrote that the qualities of
"beauty
of form", "proportion of parts", "flesh", "fatting quality" are "found
to be heredity... ...depending in some considerable degree at least, on
BREED, or what is technically termed BLOOD, namely on the specific
quality of the parents". However, little was said beyond the parents to
the grandparents or more remote [deeper] ancestral members. Wood, Orel
write that "no consideration was given to the matter of pedigree."
...and... "Ancestry was much more to be considered when exploiting an
established race than when creating a new one." [Wood, Orel, page 76]
Initially, ancestry, family
trees, or parentage beyond one or two generations of domesticated
animals was not as well known or nor as important a consideration as
the physical manifestations of phenotype: conformation, temperament,
etc. At the time of the beginnings of the breed, there was little
regard for ancestry among livestock breeders. Only when the early
English founder breeders began their creation of the Thoroughbred
horse, did parentage of the members of the new breed, gain new
importance and scrutiny. The parentage of the Eastern Oriental imports,
for the most part, was unknown. Most breeders felt that the female made
no heredity contribution and was merely a vessel of parturition. The
lack of naming many mares is an indicator of their disregard.
Therefore, beyond her sire, the parentage of the early broodmares was
usually less known than the more highly regarded sires.
Some of the most successful
of the early breeders were more enlightened. Their appreciation of
broodmares and their possible heredity influence paid their breeders
dividends. The more prescient breeders became aware of the importance
of the female, that patterns in lineages had importance, and recognized
the radical concept of maternal inheritance, probably through the
practical observation that certain, rare mares became exceptional
producers independent of the sire to which they were bred. Early,
successful female runners also contributed to an appreciation of the
contribution of the female. After all, if you owned an elite female
racehorse, wouldn't you greatly anticipate her progeny over more
ordinary females?
Horses with ancestry that
traced directly from the best-regarded progenitors of the founder stock
had higher value among horsemen of the era. This provided incentive to
record early pedigrees and to incorporate aspects of ancestry in
selection. As breeders became aware of the value of certain lineages,
techniques such as pedigree matching developed. As differing matching
schemes were tried and evaluated, a body of knowledge and pragmatic
beliefs formed a series of refined approaches to the selective mating
of racehorses.