The relationship between the circadian cycle of blood plasma analytes with feed efficiency in beef heifers

dc.contributor.advisorMiller, Stephen
dc.contributor.authorGonano, Caroline of Animal and Poultry Scienceen_US of Guelphen_US of Scienceen_US and Poultry Scienceen_US
dc.description.abstractFactors underlying biological differences in feed efficiency were investigated in order to determine if these factors could be utilized as indirect measures of feed efficiency. Residual feed intake (RFI) was determined in 36 beef heifers. Hourly blood samples were taken over 24 hours at 367 ± 15 days, 542 ± 23 days, and 704 ± 25 days of age corresponding to open, early pregnancy, and late pregnancy, respectively. Then hematological measures of basic metabolic processes that contribute significantly to energy expenditures were determined including albumin, urea, creatine kinase, glutamate dehydrogenase, aspartate aminotransferase and carbon dioxide. Creatine kinase, aspartate aminotransferase and carbon dioxide showed relationships with RFI in open heifers, urea and creatine kinase in late gestation and carbon dioxide overall. These associations tend to be reflective of differences in liver function, tissue turnover and whole body metabolism that may act as effective indirect measures of RFI.en_US
dc.description.sponsorshipOntario Cattleman's Association
dc.description.sponsorshipFarm Innovation Program
dc.description.sponsorshipBeef Cattle Research Council
dc.description.sponsorshipOntario Ministry of Agriculture and Food
dc.description.sponsorshipGrowing Forward
dc.description.sponsorshipAgricultural Adaptation Council
dc.publisherUniversity of Guelphen_US
dc.rights.licenseAll items in the Atrium are protected by copyright with all rights reserved unless otherwise indicated.
dc.subjectBeef cattleen_US
dc.subjectbiological markersen_US
dc.subjectresidual feed intakeen_US
dc.subjectvisceral organsen_US
dc.titleThe relationship between the circadian cycle of blood plasma analytes with feed efficiency in beef heifersen_US


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