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dc.contributor.authorRossini, Katherine Lynnen_US
dc.date.accessioned2011-08-06T16:02:34Z
dc.date.available2011-08-06T16:02:34Z
dc.date.issued2004-06-08en_US
dc.identifier.otheretd-07082004-152844en_US
dc.identifier.urihttp://hdl.handle.net/10919/10010
dc.description.abstractCalf health data and first lactation records for 2556 cows born in a commercial dairy herd between June 1998 and June 2001 were studied to determine the effects of calfhood disease on survival and performance. Operator-treated respiratory disease occurrences within the first year of life and digestive disease occurrences within the first 45 d of life were analyzed to determine their effects on calfhood morbidity, age at first calving, 305-d first lactation production, and mortality in first lactation. Of the 2556 records used, 2083 calves contracted respiratory or digestive disease at least once, 1254 calves had digestive disease only, 771 had respiratory disease only, and 191 calves had both diseases. Occurrence of calfhood digestive disease increased the chance of calfhood respiratory disease 2-fold. Age at first calving increased 0.53 mo with multiple occurrences of respiratory disease versus none. Calves born in the winter calved at 25.4 mo, whereas calves born in spring calved at 24.5 mo. Respiratory disease had the largest effect on calves born in the spring, resulting in 23.9 mo age at first calving for no occurrence and 25.4 mo for multiple occurrences. No significant effect of disease was detected for 305-d milk yield, fat yield, or SCC, but protein yield decreased by 0.05 kg/d with increased calf respiratory disease. Although calfhood disease had no influence on illness as a cow, disease-free calves had a 5% advantage in probability of remaining in the herd through 305-d, and an 8% advantage at 730-d compared with calves with 2 or more disease occurrences. In conclusion, calfhood occurrences of respiratory and digestive disease had a slight impact on age at first calving, depending on season of birth, and minimal impact on production performance through 305-d of first lactation. The occurrence of respiratory or digestive disease caused a decrease in survival rate from calving through 305-d in first lactation and 730 d after calving.en_US
dc.format.mediumETDen_US
dc.publisherVirginia Techen_US
dc.relation.haspartRossiniThesis.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectcalfhood diseaseen_US
dc.subjectage at first calvingen_US
dc.subjectmortalityen_US
dc.subjectmorbidityen_US
dc.titleEffects of Calfhood Respiratory and Digestive Disease on Calfhood Morbidity and First Lactation Production and Survival Ratesen_US
dc.typeThesisen_US
dc.contributor.departmentDairy Scienceen_US
dc.description.degreeMaster of Scienceen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelmastersen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineDairy Scienceen_US
dc.contributor.committeechairMcGilliard, Michael L.en_US
dc.contributor.committeememberSwecker, William S. Jr.en_US
dc.contributor.committeememberPearson, Ronald E.en_US
dc.contributor.committeememberJames, Robert E.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-07082004-152844en_US
dc.date.sdate2004-07-08en_US
dc.date.rdate2006-07-21
dc.date.adate2004-07-21en_US


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