[-] Show simple item record

dc.contributor.advisorKeisler, Duane H.eng
dc.contributor.authorMcNamara, Deniseeng
dc.date.issued2007eng
dc.date.submitted2007 Falleng
dc.descriptionThe entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.eng
dc.descriptionTitle from title screen of research.pdf file (viewed on March 7, 2008)eng
dc.descriptionThesis (Ph. D.) University of Missouri-Columbia 2007.eng
dc.description.abstract[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Serum concentrations of insulin, insulin-like growth factor I (IGF-I) and leptin were investigated relative to their association to beef carcass quality and yield grades at harvest. We observed that in a high quality, homogeneous population of beef steers, serum leptin levels correlated with USDA yield grades 1, 2, 3, and 4, but not 4 vs. 5. Serum leptin levels also discriminated (i.e. differed significantly) between the carcass quality grades of Select, Premium Choice, and Prime, while serum IGF-I levels discriminated the carcass quality grade of Prime from lower quality grades. We also determined that previously observed differences in average leptin levels, differing up to 2-fold, in previous studies were unlikely due to sample management differences such as blood collection type (serum versus plasma) or interval from blood sample collection to sample centrifugation (0, 24, or 48 hrs). We also found that Naturally managed cattle (i.e. raised without use of implants or antibiotics) had higher serum leptin levels than Traditionally managed cattle. Gender of cattle had a potent effect on serum levels of leptin and IGF-1, thus intriguing and warranting further study. Transport durations between 400 to 1100 km did not affect serum leptin or IGF-I levels in relation to quality and yield grades. A longer post slaughter chill time improved correlations between serum IGF-I levels and carcass characteristics. We also observed that in traditionally weaned cattle, leptin in blood collected 28 d prior to harvest and insulin levels in blood collected at the time of weaning were correlated with final carcass quality. Finally, we found that implanting cattle may prohibit significant correlations between serum hormone levels and carcass characteristics.eng
dc.description.bibrefIncludes bibliographical referenceseng
dc.identifier.merlinb62603383eng
dc.identifier.oclc213079090eng
dc.identifier.urihttps://doi.org/10.32469/10355/5954eng
dc.identifier.urihttps://hdl.handle.net/10355/5954
dc.languageEnglisheng
dc.publisherUniversity of Missouri--Columbiaeng
dc.relation.ispartofcommunityUniversity of Missouri--Columbia. Graduate School. Theses and Dissertationseng
dc.rightsAccess is limited to the campus of the University of Missouri--Columbia.eng
dc.subject.lcshBeef cattle -- Carcasses -- Gradingeng
dc.subject.lcshBeef -- Qualityeng
dc.subject.lcshBeef -- Yieldseng
dc.titleEndocrine associations with beef carcass quality and yieldeng
dc.typeThesiseng
thesis.degree.disciplineAnimal sciences (MU)eng
thesis.degree.grantorUniversity of Missouri--Columbiaeng
thesis.degree.levelDoctoraleng
thesis.degree.namePh. D.eng


Files in this item

[PDF]
[PDF]
[PDF]

This item appears in the following Collection(s)

[-] Show simple item record