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dc.contributor.advisorLamberson, William R.eng
dc.contributor.authorMaricle, Elizabeth Anneng
dc.date.issued2008eng
dc.date.submitted2008 Summereng
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.eng
dc.descriptionTitle from title screen of research.pdf file (viewed on August 13, 2009)eng
dc.descriptionIncludes bibliographical references.eng
dc.descriptionThesis (M.S.) University of Missouri-Columbia 2008.eng
dc.descriptionDissertations, Academic -- University of Missouri--Columbia -- Animal sciences.eng
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.eng
dc.identifier.merlin.b70627435eng
dc.identifier.oclc430344855eng
dc.identifier.otherMaricleE-072508-T11814eng
dc.identifier.urihttp://hdl.handle.net/10355/5650eng
dc.languageEnglisheng
dc.publisherUniversity of Missouri--Columbiaeng
dc.relation.ispartofcollectionUniversity of Missouri--Columbia. Graduate School. Theses and Dissertationseng
dc.subject.lcshGenotype-environment interactioneng
dc.subject.lcshAberdeen-Angus cattle -- Geneticseng
dc.subject.lcshAberdeen-Angus cattle -- Breedingeng
dc.titleGenotype by environment interaction estimated by using reaction norms in cattleeng
dc.typeThesiseng
thesis.degree.disciplineAnimal sciences (MU)eng
thesis.degree.grantorUniversity of Missouri--Columbiaeng
thesis.degree.levelMasterseng
thesis.degree.nameM.S.eng


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