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dc.contributor.authorMcCollum, F. T.
dc.contributor.authorGalyean, M. L.
dc.contributor.authorKrysl, L. J.
dc.contributor.authorWallace, J. D.
dc.date.accessioned2020-09-24T03:54:02Z
dc.date.available2020-09-24T03:54:02Z
dc.date.issued1985-11-01
dc.identifier.citationMcCollum, F. T., Galyean, M. L., Krysl, L. J., & Wallace, J. D. (1985). Cattle grazing blue grama rangeland. I. Seasonal diets and rumen fermentation. Journal of Range Management, 38(6), 539-543.
dc.identifier.issn0022-409X
dc.identifier.doi10.2307/3899748
dc.identifier.urihttp://hdl.handle.net/10150/645444
dc.description.abstractFour field trials were conducted from early August to late October, 1982, on blue grama (Bouteloua gracilis) rangeland in south-central New Mexico to examine relationships among grazing season, diet botanical and chemical composition, and rumen fermentation in beef steers (Bos taurus). Diets contained an average of 83% grasses and 17% forbs from early August through late September and 77% forbs in late October. Cell wall content of the diet decreased from the early growing season (74.9%) through the onset of dormancy (64.9%) while acid detergent fiber and lignin increased (41.9 to 52.9% and 5.2 to 12.7%, respectively) and crude protein content declined from 18.4 to 11.7%. Soluble and insoluble nitrogen (N) fractions of the diet reflected crude protein; from 13 to 36% of N was in unavailable forms. The extent of in vitro organic matter digestion declined from the early growing season (66.5%) through onset of dormancy (47.9%). Ruminal ammonia concentrations declined as season progressed: 6.0 mg/100ml was the lowest concentration observed. Declining diet quality was accompanied by an upward shift in digesta pH and altered proportions of volatile fatty acids (VFA) in rumen contents. Total VFA concentration was highest in late August (106.3 mmoles/liter). Ruminal measures generally reflected changes in dietary protein and digestibility but concentrations could also reflect changes in digesta flow rates. Finally, data suggest that crude protein may not be a good measure of protein supply to livestock grazing on ranges with diverse forage types.
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.subjectBouteloua gracilis
dc.subjectdiets
dc.subjectrumen fermentation
dc.subjectseasonal variation
dc.subjectrangelands
dc.subjectgrazing
dc.subjectNew Mexico
dc.subjectbeef cattle
dc.subjectforage
dc.titleCattle Grazing Blue Grama Rangeland. I. Seasonal Diets and Rumen Fermentation
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.volume38
dc.source.issue6
dc.source.beginpage539-543
refterms.dateFOA2020-09-24T03:54:02Z


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