- One's line of descent; ancestry: a person of noble breeding.
- Training in the proper forms of social and personal conduct.
- Production of offspring or young.
- The propagation of animals or plants.
|
Results for breeding
|
On this page:
|
The application of genetic principles to improving heredity for economically important traits in domestic animals. Examples are improvement of milk production in dairy cattle, meatiness in pigs, feed requirements or growth rate in beef cattle, and egg production in chickens. Selection permits the best parents to leave more offspring in the next generation than do poor parents.
Selection is the primary tool for generating directed genetic changes in animals. It may be concentrated on one characteristic, may be directed independently on several traits, or may be conducted on an index or total score which includes information on several traits. In general, the third method is preferable when several important heritable traits need attention. In practice, selection is likely to be a mixture of the second and third methods.
Heritability, the fraction of the total variation in a trait that is due to additive genetic differences, is a key parameter in making decisions in selection. Most traits are strongly to moderately influenced by environmental or managemental differences. Therefore, managing animals to equalize environmental influences on them, or statistically adjusting for environmental differences among animals, is necessary to accurately choose those with the best inheritance for various traits.
The improvement achieved by selection is directly related to the accuracy with which the breeding values of the subjects can be recognized. Accuracy, in turn, depends upon the heritabilities of the traits and upon whether they can be measured directly upon the subjects for selection (mass selection), upon their parents (pedigree selection), upon their brothers and sisters (family selection), or upon their progeny (progeny testing). For traits of medium heritability, the following sources of information are about equally accurate for predicting breeding values of subjects: (1) one record measured on the subject; (2) one record on each ancestor for three previous generations; (3) one record each on five brothers or sisters where there is no environmental correlation between family members; and (4) one record each on five progeny having no environmental correlations, each from a different mate.
Propagation of improved animal stocks is achieved primarily with purebred strains descended from imported or locally developed groups or breeds of animals which have been selected and interbred for a long enough period to be reasonably uniform for certain trademark characteristics, such as coat color. Because the number of breeding animals is finite and because breeders tend to prefer certain bloodlines and sires, some inbreeding occurs within the pure breeds, but this has not limited productivity in most of these breeds. Crossbreeding makes use of the genetic phenomenon of heterosis. Heterosis is improved performance of crossbred progeny, exceeding that of the average performance of their parents. Most commercial pigs, sheep, and beef cattle are produced by crossbreeding. See also Genetics.
Advances in a variety of technologies have application for improvement of domestic animals, including quantitative genetics, reproductive physiology, and molecular genetics. Quantitative geneticists use statistical and genetic information to improve domestic animals. Typically a statistical procedure is used to rank animals based on their estimated breeding values for traits of economic importance. The statistical procedures used allow ranking animals across herds or flocks, provided the animals in different herds or flocks have relatives in common. The primary contribution of reproductive physiology to genetic improvement is to reduce the generation interval. If genetic improvement is increasing at the same rate per generation, more generations can be produced for a fixed time, and thus more gain per unit of time. The most important development was artificial insemination, which allows extensive use of superior males. Another development was embryo transplantation, which allows more extensive use of females. Cloning is a relatively new technique, by which whole and healthy animals have been produced that have the same DNA as the animal from which the cells were taken.
Due to advances in molecular genetics, knowledge is increasing regarding the location of genes on chromosomes and the distance between the genes. In domestic animals, polymorphisms (changes in the order of the four bases) that are discovered in the DNA may be associated with economic traits. When the polymorphisms are associated with or code for economic traits, they are called quantitative trait loci (QTL). When a few or several quantitative trait loci are known that control a portion of the variability in a trait, increasing the frequencies of favorable alleles can enhance the accuracy of selection and augment production. Another use of molecular genetics is to detect the genes that code for genetically predetermined diseases. An example is the bovine leukocyte deficiency gene, which does not allow white blood cells to migrate out of the blood supply into the tissues to fight infection. The calves perish at a young age. Screening all sires that enter artificial breeding organizations and not using sires that transmit the defect has effectively controlled this condition.
noun
For more information on breeding, visit Britannica.com.
Inbreeding produces families or lines with increasing degrees of genetic uniformity, or homozygosity, in successive generations. In highly homozygous families, dominant genes are uniformly transmitted and expressed; recessive genes are also more likely to be expressed, and to produce undesirable traits, including loss of general vigor and fertility. In some plants, such as wheat, that are naturally self-fertilizing and homozygous, deleterious traits are readily eliminated by natural selection; there is no loss of vigor.
In naturally cross-pollinated or open-pollinated plants, and in animals, loss of vigor in inbred lines can be restored by outbreeding to unrelated or distantly related lines; a first-generation hybrid is more vigorous than either of its purebred parents. Animal breeders exploit the phenomenon of hybrid vigor, or heterosis, in producing crossbred cattle, sheep, swine, and other domestic animals. Much of the corn (Zea mays) grown in the United States and other agriculturally developed countries is the hybrid of two different inbred lines, or the double-cross hybrid of four inbred lines.
Selective breeding developed with the domestication of useful species during the Neolithic period: the oldest known remains of cultivated crops and domestic animals show signs of purposeful improvement. For centuries, selective breeding proceeded empirically. Beginning in the 18th cent. various breed associations formed to register purebred herds and flocks and keep track of pedigrees. Plant breeders collected seeds and documented their genealogies. The basic principles of heredity, originally published by the Austrian biologist Gregor Mendel (see Mendel, Gregor Johann) in 1866, were rediscovered in 1900.
With subsequent discoveries in genetics, and progress in artificial insemination and other breeding techniques, plant and animal breeding have become increasingly scientific. More recent advances in biotechnology and genetic engineering allow breeders to transfer specific genes and gene complexes among plants and animals, bypassing the limitations of conventional sexual reproduction. Knowledge of genomes and the techniques of genetics also enhance conventional breeding: In marker-assisted breeding, genetic markers are used to identify the desired characteristics in a plant while it is a seedling, reducing the time needed to select individuals with those traits.
1. pedigree.
2. the physical act of mating.
3. capable of being used for reproduction.
4. controlled propagation of animals or plants.
Breeding generally refers to the act of biological reproduction or but may also refer to:
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
Dansk (Danish)
n. - formering, avl
idioms:
Nederlands (Dutch)
teelt, fokkerij, manieren
Français (French)
n. - procréation, reproduction, élevage, bonnes manières
idioms:
Deutsch (German)
n. - Anbau, Zucht, Manieren
idioms:
Ελληνική (Greek)
n. - πολλαπλασιασμός, αναπαραγωγή, ανατροφή, τρόποι, καταγωγή
idioms:
Italiano (Italian)
coltura, allevamento, educazione
idioms:
Português (Portuguese)
n. - procriação (f)
idioms:
Русский (Russian)
разведение, воспитание
idioms:
Español (Spanish)
n. - cría, cultivo, modales, educación
idioms:
Svenska (Swedish)
n. - alstring, uppfödande, avel, fortplantning
中文(简体) (Chinese (Simplified))
生育, 生殖, 饲养, 繁殖, 培植
idioms:
中文(繁體) (Chinese (Traditional))
n. - 生育, 生殖, 飼養, 繁殖, 培植
idioms:
日本語 (Japanese)
n. - 繁殖, 飼育, 家系, 保育, しつけ, 教養
idioms:
العربيه (Arabic)
(الاسم) تربيه ( الخيل), تهذيب, حسن السلوك
עברית (Hebrew)
n. - גידול, נימוס, חינוך
If you are unable to view some languages clearly, click here.
To select your translation preferences click here.
| Argyranthemum Frutescens Breeding |
Join the WikiAnswers Q&A community. Post a question or answer questions about "breeding" at WikiAnswers.
Copyrights:
![]() | Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2007. Published by Houghton Mifflin Company. All rights reserved. Read more | |
![]() | Sci-Tech Encyclopedia. McGraw-Hill Encyclopedia of Science and Technology. Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved. Read more | |
![]() | Thesaurus. Roget's II: The New Thesaurus, Third Edition by the Editors of the American Heritage® Dictionary Copyright © 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved. Read more | |
![]() | Antonyms. © 1999-2008 by Answers Corporation. All rights reserved. Read more | |
![]() | Britannica Concise Encyclopedia. Britannica Concise Encyclopedia. © 2006 Encyclopædia Britannica, Inc. All rights reserved. Read more | |
![]() | Columbia Encyclopedia. The Columbia Electronic Encyclopedia, Sixth Edition Copyright © 2003, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/ Read more | |
![]() | Veterinary Dictionary. Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved. Read more | |
![]() | Wikipedia. This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Breeding". Read more | |
![]() | Translations. Copyright © 2007, WizCom Technologies Ltd. All rights reserved. Read more |
Mentioned In: