Implications of the ability of Enterococcus spp. to survive the ensiling process and bovine gastrointestinal tract on the risk of bovine mastitis

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dc.contributor.authorMasiello, Stephanie Noelleen
dc.contributor.committeechairPetersson-Wolfe, Christina S.en
dc.contributor.committeememberElvinger, Francois C.en
dc.contributor.committeememberSumner, Susan S.en
dc.contributor.committeememberAkers, Robert Michaelen
dc.contributor.committeememberMullarky, Isis K.en
dc.contributor.departmentDairy Scienceen
dc.date.accessioned2014-03-14T20:32:21Zen
dc.date.adate2010-03-11en
dc.date.available2014-03-14T20:32:21Zen
dc.date.issued2010-01-25en
dc.date.rdate2010-03-11en
dc.date.sdate2010-03-03en
dc.description.abstractThree studies were conducted to assess if the ability of Enterococcus spp. surviving the ensiling process and bovine gastrointestinal tract could impact risk of bovine mastitis. The first study determined ability of enterococci to survive 3 wk ensiling. Grass and corn crops were divided into 3 treatments: 2 commercial silage inoculants, 1 negative control. After wk 1, 2, and 3 of ensiling, dry matter and bacterial enumeration were performed. Addition of silage inoculant led to greater levels of enterococci in grass silage compared with negative control levels, but showed less difference in inoculated corn silage. The second study quantified enterococci shedding rates in lactating dairy cows. Using a 4 x 4 Latin Square design, lactating, ruminally fistulated Holsteins were inoculated with enterococcal isolates from silage inoculants, ensiled forages, or clinical mastitis cases. Over the 4-period study, each period consisted of rumen and fecal sampling (2 wk) followed by a wash period (10 d). There were no significant differences in rumen or fecal enterococci levels between the 4 treatments. Both rumen and fecal enterococci levels showed significant differences between baseline and treatment periods (period 3, 4). The third study analyzed similarity in enterococcal isolates of silage and bovine origin using pulsed-field gel electrophoresis patterns from SmaI restrictions. Dendogram analysis showed none of the isolates met or were greater than a 75% genetic similarity and produced a genetically diverse population. Results suggest Enterococcus spp. from silage inoculants are not likely to contribute to an increased risk of enterococcal bovine mastitis.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-03032010-104810en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-03032010-104810/en
dc.identifier.urihttp://hdl.handle.net/10919/31403en
dc.publisherVirginia Techen
dc.relation.haspartMasiello_SN_T_2010.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectbovine mastitisen
dc.subjectsheddingen
dc.subjectsilage inoculanten
dc.subjectEnterococcus spp.en
dc.titleImplications of the ability of Enterococcus spp. to survive the ensiling process and bovine gastrointestinal tract on the risk of bovine mastitisen
dc.typeThesisen
thesis.degree.disciplineDairy Scienceen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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