A study of weaning weights in Hereford cattle in the state of Rio Grande do Sul, Brazil

dc.contributor.author Fries, Luiz
dc.contributor.department Animal Science
dc.date 2018-08-15T19:35:01.000
dc.date.accessioned 2020-07-02T06:05:09Z
dc.date.available 2020-07-02T06:05:09Z
dc.date.copyright Sun Jan 01 00:00:00 UTC 1984
dc.date.issued 1984
dc.description.abstract <p>To allow for the identification of genetic differences in preweaning growth among Hereford calves participating in a record of performance program, in the state of Rio Grande do Sul, Brazil, a model should contain, at least, the following environmental explanatory variables: contemporary group classes, age of dam spline-regressors nested in sex of calf, nursing status at last mating season of the dam classes, date of birth of calf spline-regressors nested in calving seasons, and linear and quadratic age of calf regressors;Generalized least squares estimates of the above environmental effects and of sire effects nested in sets were obtained. Restricted maximum likelihood estimates of error and sire variances indicate that selection for weaning weight would respond to selection. To obtain these estimates a combination of the Common Intercept Approach and of Givens rotations was used to perform the iterations and to obtain the converged values in a fast and efficient manner. Robust estimation techniques are discussed and preliminary results show that such techniques could aid in animal selections;Operational methods to optimally solve animal breeding problems characterized by the sequential accumulation of batches of field data are investigated or discussed.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/rtd/8163/
dc.identifier.articleid 9162
dc.identifier.contextkey 6330755
dc.identifier.doi https://doi.org/10.31274/rtd-180813-6829
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath rtd/8163
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/81121
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/rtd/8163/r_8505817.pdf|||Sat Jan 15 02:07:19 UTC 2022
dc.subject.disciplines Agriculture
dc.subject.disciplines Animal Sciences
dc.subject.disciplines Genetics
dc.subject.keywords Animal science
dc.subject.keywords Animal breeding
dc.title A study of weaning weights in Hereford cattle in the state of Rio Grande do Sul, Brazil
dc.type article
dc.type.genre dissertation
dspace.entity.type Publication
relation.isOrgUnitOfPublication 85ecce08-311a-441b-9c4d-ee2a3569506f
thesis.degree.level dissertation
thesis.degree.name Doctor of Philosophy
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