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Effects of endocrine modifiers on growth, carcass characteristics, and blood and tissue metabolites of finishing beef cattle

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dc.contributor.authorBryant, Anthony C., author
dc.contributor.authorEngle, Terry E., advisor
dc.date.accessioned2024-03-13T18:50:53Z
dc.date.available2024-03-13T18:50:53Z
dc.date.issued2008
dc.description.abstractThe effects of vitamin A and the interaction of steroids and beta-adrenergic agonists on growth and carcass performance, tissue metabolite profiles, and lipogenic enzyme activity were evaluated in beef cattle. In 1 experiment steers were fed 1 of 5 supplemental levels of vitamin A (0, 1,103, 2,205, 4,410, or 8,820 IU/kg DM). Final BW, G:F, ADG, HCW, LM area, marbling, and quality grade distribution did not differ among treatments. Except for d 56, no correlations between marbling score and tissue retinol concentrations or vitamin A intake were found. A negative correlation between liver retinol and α-tocopherol was observed, which may have potential health implications. Results suggest that vitamin A supplementation up to twice the NRC-suggested concentration has little effect on performance, marbling, or lipogenic enzyme activity in yearling steers and further suggest that 2,205 IU supplemental vitamin A/kg of DM is adequate for growing/finishing beef steers.
dc.description.abstractIn 2 separate experiments, factorial arrangements of implant and beta-adrenergic agonist dosages were evaluated for effects on performance, carcass traits, blood metabolites, and lipogenic enzyme activity. In Exp. 1, steers were assigned to ractopamine (RAC; 0, 100, or 200 mg·steer-1·d-1) and implant/reimplant (IMP; None/None, Revalor-S/None, or Revalor-IS/Revalor-S) regimens, whereas in Exp. 2, heifers were assigned to ractopamine (0 or 250 mg·heifer-1·d-1) and implant (none, Finaplix, or Revalor-200) treatments. No RAC x IMP interactions were noted for most carcass and performance traits. Cattle implanted or fed supplemental ractopamine had significantly greater final BW, HCW, ADG, and G:F than the respective controls. Despite no detectable difference in empty body fat (EBF), both marbling and quality grade were decreased significantly by IMP and numerically by RAC. Implanted cattle had decreased cortisol and increased GH, IGF-1, and NEFA. Although an IMP x RAC interaction was detected, BUN was decreased by IMP and RAC. No clear trends in lipogenesis were found. These data show that quality grade and marbling can differ significantly at equal EBF in finishing beef steers. Altogether, these data suggest that the modes of action of IMP and RAC are independent. Further research is needed to elucidate the exact mode of actions of these growth-enhancing products.
dc.format.mediumborn digital
dc.format.mediumdoctoral dissertations
dc.identifierETDF_Bryant_2008_3346439.pdf
dc.identifier.urihttps://hdl.handle.net/10217/237603
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado State University. Libraries
dc.relation.ispartof2000-2019
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.
dc.rights.licensePer the terms of a contractual agreement, all use of this item is limited to the non-commercial use of Colorado State University and its authorized users.
dc.subjectbeef cattle
dc.subjectblood
dc.subjectbody composition
dc.subjectcarcass characteristics
dc.subjectendocrine modifiers
dc.subjectfinishing cattle
dc.subjecttissue metabolites
dc.subjectphysiology
dc.subjectanimal sciences
dc.titleEffects of endocrine modifiers on growth, carcass characteristics, and blood and tissue metabolites of finishing beef cattle
dc.typeText
dcterms.rights.dplaThis Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
thesis.degree.disciplineAnimal Sciences
thesis.degree.grantorColorado State University
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy (Ph.D.)

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