Animal breeding is a branch of
animal science that addresses the evaluation (using
best linear unbiased prediction and other methods) of the genetic value (estimated breeding value, EBV) of livestock. Selecting for breeding animals with superior EBV in growth rate, egg, meat, milk, or wool production, or with other desirable traits has revolutionized livestock production throughout the entire world. The scientific theory of animal breeding incorporates
population genetics,
quantitative genetics,
statistics, and recently
molecular genetics and is based on the pioneering work of
Sewall Wright,
Jay Lush, and
Charles Henderson.
Breeding stock
Breeding stock is a group of animals used for the purpose of planned breeding. When individuals are looking to breed animals, they look for certain valuable traits in
purebred animals, or may intend to use some type of
crossbreeding to produce a new type of stock with different, and presumably superior abilities in a given area of endeavor. For example, when breeding swine for meat, the "breeding stock should be sound, fast growing, muscular, lean, and reproductively efficient."[1] The "subjective selection of breeding stock" in horses has led to many
horse breeds with particular performance traits.[2] While breeding animals is common in an
agricultural setting, it is also a common practice for the purpose of selling animals meant as
pets, such as
cats,
dogs,
horses, and
birds, as well as less common animals, such as
reptiles or some
primates.
Mating animals of the same breed for maintaining such breed is referred to as purebred breeding. Opposite to the practice of mating animals of different breeds, purebred breeding aims to establish and maintain stable traits, that animals will pass to the next generation. By "breeding the best to the best", employing a certain degree of
inbreeding, considerable
culling, and selection for "superior" qualities, one could develop a bloodline or "
breed" superior in certain respects to the original base stock.
Such animals can be recorded with a
breed registry, the organisation that maintains
pedigrees and/or
stud books.
The observable phenomenon of
hybrid vigor stands in contrast to the notion of breed purity.
For laboratory purposes, organisms such as mice have been inbred to 100% pure lines, as offered for sale by the
Jackson laboratory. But this is highly unusual and difficult to do for most organisms, in whose populations all individuals harbor recessive, deleterious gene variants (alleles).
Backyard breeding
In the United States, a backyard breeder is someone who breeds animals, often without registration and with a focus on profit. In some cases, the animals are inbred narrowly for looks, with little regard to health.[3] The term is considered derogatory. If a backyard
dog breeder has a significant number of breeding animals, they become associated with
puppy mills. Most puppy mills are licensed with the USDA.[4]
Kempthorne, O (1957), Introduction to Statistic Genetics, John Wiley & Sons
Van Vleck; L. D.; Searle; S. R. (1979), Variance components and animal breeding: proceedings of a conference in honor of C.R. Henderson, Ithaca, N.Y.: Cornell University
Henderson, CR (1984), Applications of linear models in animal breeding, Guelph, Ont: University of Guelph,
ISBN0-88955-030-1
Hammond K. Gianola, D. (1990), Advances in Statistical Methods for Genetic Improvement of Livestock (Advanced Series in Agricultural Sciences), Springer-Verlag Berlin and Heidelberg GmbH & Co. K,
ISBN3-540-50809-0