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dc.contributor.authorCochran, R. C.
dc.contributor.authorAdams, D. C.
dc.contributor.authorGalyean, M. L.
dc.contributor.authorWallace, J. D.
dc.date.accessioned2020-09-24T03:37:51Z
dc.date.available2020-09-24T03:37:51Z
dc.date.issued1987-03-01
dc.identifier.citationCochran, R. C., Adams, D. C., Galyean, M. L., & Wallace, J. D. (1987). Examination of methods for estimating rate of passage in grazing steers. Journal of Range Management, 40(2), 105-108.
dc.identifier.issn0022-409X
dc.identifier.doi10.2307/3899197
dc.identifier.urihttp://hdl.handle.net/10150/645330
dc.description.abstractUnderstanding how rate of passage estimates are influenced by procedural variations may facilitate standardization of methodology and enhance comparisons among studies. Therefore, 12 ruminal-fistulated beef steers (mean wt. = 294 kg) were used in two 6-day grazing trials to evaluate influences of sampling site, intraruminal mixing, and mathematical model on particle passage rate estimates. Steers grazed a 13-ha pasture of immature crested wheatgrass. We estimated particle passage rate from the rumen by intraruminal administration of a pulse dose of Yb-labeled forage followed by serial collection of ruminal digesta or fecal samples. Treatments were (1) rectal sampling; (2) ruminal sampling-ruminal contents mixed before subsampling digesta; (3) ruminal sampling-ruminal contents not mixed before subsampling digesta. All steers were fitted with vibracorders to monitor grazing time before and during sampling periods. Fecal Yb curves were fitted with a one compartment, time-dependent (ICMPT-TD), a two-compartment, sequential time-dependent-time-independent (2CMPT-TD), and a two-compartment, time-independent (2CMPT-TI) model. All ruminal Yb curves were fitted with a single exponential decay model. Comparisons among models were limited to rate constants associated with the slower escape process. Intraruminal mixing did not alter (P>0.10) passage rates. The 2CMPT-TD model failed to fit some fecal profiles. Particle passage rates from the 2CMPT-TI model were greater (P<0.05) than those from the ICMPT-TD model. Similarity among passage rate constants derived from fecal Yb curves and those derived by semilogarithmic regression of ruminal Yb concentration on time depended on the model used to fit fecal Yb curves. Grazing time decreased (P<0.01) during intensive sampling periods. We conclude that for steers grazing immature grass pastures, intraruminal mixing before subsampling does not significantly alter rate of passage estimates; however, site of sampling and mathematical model may be important factors to consider in choosing appropriate methodology for estimating rate of passage.
dc.language.isoen
dc.publisherSociety for Range Management
dc.relation.urlhttps://rangelands.org/
dc.rightsCopyright © Society for Range Management.
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/
dc.subjectytterbium
dc.subjectmathematical models
dc.subjectAgropyron desertorum
dc.subjectestimation
dc.subjectsampling
dc.subjectdigestion
dc.subjectsteers
dc.subjectdigesta
dc.subjectkinetics
dc.subjecttransit time
dc.subjectgrazing
dc.titleExamination of Methods for Estimating Rate of Passage in Grazing Steers
dc.typetext
dc.typeArticle
dc.identifier.journalJournal of Range Management
dc.description.noteThis material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.
dc.description.collectioninformationThe Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information.
dc.eprint.versionFinal published version
dc.description.admin-noteMigrated from OJS platform August 2020
dc.source.volume40
dc.source.issue2
dc.source.beginpage105-108
refterms.dateFOA2020-09-24T03:37:51Z


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