Heritability estimates for calving date in Simmental cattle

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dc.contributor.authorMeacham, Nancy S.en
dc.contributor.committeechairNotter, David R.en
dc.contributor.committeememberPearson, Ronald E.en
dc.contributor.committeememberMarlowe, Thomas J.en
dc.contributor.committeememberBeal, Wilfred E.en
dc.contributor.committeememberGerken, Hubert J. Jr.en
dc.contributor.departmentAnimal Scienceen
dc.date.accessioned2014-03-14T21:49:54Zen
dc.date.adate2012-11-17en
dc.date.available2014-03-14T21:49:54Zen
dc.date.issued1987-05-15en
dc.date.rdate2012-11-17en
dc.date.sdate2012-11-17en
dc.description.abstractVariation among sires in daughters' reproductive performance was analyzed using data on 4,360 cows from nine herds obtained from the American Simmental Association. Cows were required to have at least 50% Simmental breeding, to have calved first at 2 yr of age and to have been born and subsequently calved in the same herd and season. Traits analyzed included first and second calving dates, first calving interval and the percentage of cows that returned to calve in the same season as 3-yr-olds. Data were adjusted for effects of percentage Simmental and first-calf calving ease score. At second calving, purebred Simmentals calved 1.7 ± 1.2 d later than 75% Simmental cattle and 5.1 ± 1.4 d later than 50% Simmental cattle. When compared to cows that calved without assistance at first calving, cows experiencing easy pulls were 1.7 ± 1.4% less likely to calve as 3-yr-olds and had 4.9 ± 1.0 d longer calving intervals. Cows with hard pulls were 9.0 ± 2.1% less likely to return and had 6.5 ± 1.6 d longer calving intervals. Cows requiring Cesarean section were 23.1± 2.5% less likely to return and had 19.6 ± 2.4 d longer calving intervals. Heritability estimates were .17 ± .04 for first calving date, .07 ± .06 for second calving date, .04:105 for calving interval and .11 ± .04 for percent return. Calving interval does not appear to be a useful selection criterion to improve reproduction. Phenotypic and genetic correlations of first calving date with calving interval were -.58 and -.83 ± .37, respectively. The genetic correlation between first and second calving dates was .66 ± .41. Given current data recording procedures, calving date appears to be the most useful potential selection criterion to improve reproductive fitness.en
dc.description.degreeMaster of Scienceen
dc.format.extentiv, 38 leavesen
dc.format.mediumBTDen
dc.format.mimetypeapplication/pdfen
dc.identifier.otheretd-11172012-040109en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-11172012-040109/en
dc.identifier.urihttp://hdl.handle.net/10919/45782en
dc.publisherVirginia Techen
dc.relation.haspartLD5655.V855_1987.M428.pdfen
dc.relation.isformatofOCLC# 16781872en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V855 1987.M428en
dc.subject.lcshBeef cattle -- Breedingen
dc.subject.lcshCattle -- Parturitionen
dc.subject.lcshDairy cattle -- Breedingen
dc.subject.lcshSimmental cattleen
dc.titleHeritability estimates for calving date in Simmental cattleen
dc.typeThesisen
dc.type.dcmitypeTexten
thesis.degree.disciplineAnimal Scienceen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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