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dc.contributor.advisorLamberson, William R.en_US
dc.contributor.authorMaricle, Elizabeth Annen_US
dc.date.issued2008eng
dc.date.submitted2008 Summeren
dc.descriptionThe entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.en_US
dc.descriptionTitle from title screen of research.pdf file (viewed on August 13, 2009)en_US
dc.descriptionIncludes bibliographical references.en_US
dc.descriptionThesis (M.S.) University of Missouri-Columbia 2008.en_US
dc.descriptionDissertations, Academic -- University of Missouri--Columbia -- Animal sciences.en_US
dc.description.abstractThe objective of this study was to evaluate GxE by comparing reaction norms among U.S. Angus bulls. Dependent variables were adjusted weights at birth, 205 d weaning, and 365 d yearling. Environments were defined as progeny groups based upon data record location. Data were included in the analysis if each sire had at least 100 progeny, at least 6 progeny per environment, and at least 5 environments represented, while each environment required at least 6 qualifying bulls. The average performance of progeny within each herd environment was defined as the environmental mean. Four statistical models were analyzed using herd environment (categorical (CM) and genotype by environment (GEM)) or environmental mean (continuous environment (CEM) and random regression (RRM)) for estimating breeding values and heritabilities. Fixed effects included year-season, contemporary group, and sex. The RRM produced reaction norms for each bull which were calculated by regressing progeny means within an environment on environment means (SAS PROC GLM and ASREML). Regression coefficients differed among bulls for all traits (P [less than] 0.0001). Heritability estimates with pedigree information ranged from 0.293 to 0.401 for birth weight; 0.141 to 0.289 for weaning weight; and 0.147 to 0.259 for yearling weight. The RRM had the best fit when evaluated using environmental mean. These results suggest that bulls differ in the consistency of their progeny's performance across environments. Estimates of genetic merit of regressions from reaction norms may be a useful selection tool for ranking bulls to be used across diverse environments.en_US
dc.identifier.merlin.b70627435en_US
dc.identifier.oclc430344855en_US
dc.identifier.otherMaricleE-072508-T11814en_US
dc.identifier.urihttp://hdl.handle.net/10355/5650
dc.publisherUniversity of Missouri--Columbiaen_US
dc.relation.ispartofcollection2008 Freely available theses (MU)
dc.relation.ispartofcommunityUniversity of Missouri-Columbia. Graduate School. Theses and Dissertations. Theses. 2008 Theses
dc.subject.lcshGenotype-environment interactionen_US
dc.subject.lcshAberdeen-Angus cattle -- Geneticsen_US
dc.subject.lcshAberdeen-Angus cattle -- Breedingen_US
dc.titleGenotype by environment interaction estimated by using reaction norms in cattleen_US
dc.typeThesisen_US
thesis.degree.disciplineAnimal sciences (MU)eng
thesis.degree.grantorUniversity of Missouri--Columbiaeng
thesis.degree.levelMastersen_US
thesis.degree.nameM.S.en_US


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