Analysis of newborn calf body measurements and relationship of calf shape to sire breeding values for birth weight and calving ease

Simple item page
dc.contributor.authorNugent, Russell Arthuren
dc.contributor.committeechairNotter, D.R.en
dc.contributor.committeememberBeal, W.E.en
dc.contributor.committeememberFrahm, R.R.en
dc.contributor.committeememberThatcher, Craig D.en
dc.contributor.committeememberVinson, William E.en
dc.contributor.departmentAnimal Science (Breeding and Genetics)en
dc.date.accessioned2014-03-14T21:16:52Zen
dc.date.adate2008-07-28en
dc.date.available2014-03-14T21:16:52Zen
dc.date.issued1990en
dc.date.rdate2008-07-28en
dc.date.sdate2008-07-28en
dc.description.abstractThese studies were conducted to define calf body shape, to test for relationships between calf shape and sire expected progeny differences for birth weight (BWTEPD) and first-calf calving ease (CEEPD) and to evaluate the efficacy of calf shape as a selection criterion for reduction of calving difficulty. Birth weight (BW), head circumference (HC), hip width (HW), shoulder width, body length (BL), cannon circumference (CC), cannon length (CL) and heart girth (HG) were measured at birth on 1,016 calves sired by Angus, Polled Hereford and Simmental bulls. In the Angus- and Polled Hereford-sired calves, sire effects were present for BW-adjusted residuals of CC. Additionally, HW, BL and HG residuals differed among half-sib groups for the Polled Hereford-sired calves. Thus, calf body measure differences independent of BW were in part attributable to sire. Multivariate factor analysis was used to identify underlying skeletal width and frame dimensions of calf shape in both breeds. After adjustment of body measures for differences in BW, a positive relationship of BWTEPD with HC and CC and a negative relationship between CEEPD and CC existed. Further adjustment for BWTEPD removed effects of CEEPD on CC. Thus, BWTEPD influenced calf shape independent of BW, but shape was not related to CEEPD independent of BWTEPD. Simmental bulls were divergently selected on CEEPD relative to BWTEPD so that body measures of calves from sires whose progeny tended to be born with more or with less dystocia than expected from BWTEPD could be obtained. Differences in CL and CC at constant BW were in part attributable to sire. Underlying shape factors were similar to those of the other breeds. Sire BWTEPD was positively related to CC and HC independent of BW. However, a relationship between body measures and CEEPD existed only at constant BW and BWTEPD. Calf shape independent of BW was also not different among calves born unassisted and assisted. Estimates of heritability, repeatability and birth to weaning relationships for each BW-residual body measure were generally not significant. Overall, sire BWTEPD was related to calf shape independent of BW. However, increases in skeletal dimensions were not related to either observed calving difficulty nor sire CEEPD independent of BW. Selection for reduced calving difficulty should not be based on calf body shape.en
dc.description.degreePh. D.en
dc.format.extentviii, 175 leavesen
dc.format.mediumBTDen
dc.format.mimetypeapplication/pdfen
dc.identifier.otheretd-07282008-135956en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-07282008-135956/en
dc.identifier.urihttp://hdl.handle.net/10919/38998en
dc.language.isoenen
dc.publisherVirginia Techen
dc.relation.haspartLD5655.V856_1990.N833.pdfen
dc.relation.isformatofOCLC# 21717364en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V856 1990.N833en
dc.subject.lcshBeef cattle -- Parturitionen
dc.subject.lcshBeef cattle -- Weighten
dc.titleAnalysis of newborn calf body measurements and relationship of calf shape to sire breeding values for birth weight and calving easeen
dc.typeDissertationen
dc.type.dcmitypeTexten
thesis.degree.disciplineAnimal Science (Breeding and Genetics)en
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

Files

Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
LD5655.V856_1990.N833.pdf
Size:
8.29 MB
Format:
Adobe Portable Document Format
Description:
Download

Collections

Doctoral Dissertations