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dc.contributor.authorBergmann, José Aurélio Garciaen_US
dc.date.accessioned2014-03-14T21:14:06Z
dc.date.available2014-03-14T21:14:06Z
dc.date.issued1992-07-04en_US
dc.identifier.otheretd-06062008-170125en_US
dc.identifier.urihttp://hdl.handle.net/10919/38383
dc.description.abstractData from 946 Angus and 351 Simmental females were used to quantify relationships between calfhood and early-life traits of females with fertility in the fust two breeding seasons, and with calf production in the fITst, in three and in eleven years of life. These traits were used to develop pre· diction equations for fertility using logistic regression methodology. For productive performance, three methodologies were compared: least squares, ridge regression and principal components re· gression. For heifers of both breeds, fertility was associated with birth date, weaning weight ratio and weaning-yearling relative growth rate (RGR). The only calfhood trait that consistently affected fertility in the second breeding season was birth weight of the cow. Fertility of fITst parity Simmentals was also associated with birth-yearling RGR. First calving season traits explained a higher proportion of variation in second breeding season fertility than calfhood traits of the cow. Among these traits, calving date, calving ease score and sex of the calf were the most important. The combination of birth date and weaning-yearling RGR produced the best models to predict heifer fertility for both breeds. Fertility in the second breeding season was best predicted for Angus cows when calving date, calving ease score and sex of the calf were used as regressors. For Simmental cows, fertility in the second breeding season was best predicted from birth weight of the calf and calving ease score.en_US
dc.format.mediumBTDen_US
dc.publisherVirginia Techen_US
dc.relation.haspartLD5655.V856_1992.B423.pdfen_US
dc.subjectSimmental cattle.en_US
dc.subject.lccLD5655.V856 1992.B423en_US
dc.titleRelationships among heifer traits, early-life productive traits, and lifetime productivity within Angus and Simmental female cattleen_US
dc.typeDissertationen_US
dc.contributor.departmentAnimal Scienceen_US
dc.description.degreePh. D.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineAnimal Scienceen_US
dc.contributor.committeechairHohenboken, William D.en_US
dc.contributor.committeememberFrahm, Richard R.en_US
dc.contributor.committeememberPearson, Ronald E.en_US
dc.contributor.committeememberNotter, David R.en_US
dc.contributor.committeememberSiegel, Paul B.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-06062008-170125/en_US
dc.date.sdate2008-06-06en_US
dc.date.rdate2008-06-06
dc.date.adate2008-06-06en_US


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