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dc.contributor.authorRobbins, Kathryn Bach
dc.description181 pages
dc.description.abstractDairy cows transitioning from late gestation to early lactation visit a state of energy deficit due to increased energy demands of lactation coupled with decreases in dry matter intake. Inability to navigate this period effectively leads to excessive energy deficit (EED) and sets cows up for a lactation marked with reduced health, production, reproductive efficiency and lifespan within the herd. With effective monitoring of EED and other early lactation disease, we can identify animals at risk, those requiring treatment, as well as areas of management needing reevaluation. The objectives herein were to: 1) assess the diagnostic performance of newly developed handheld meters for use in on-farm EED diagnosis; 2) establish the association of early lactation Fourier transform mid-infrared (FTIR) predicted milk and blood constituents with the risk of adverse events and early-lactation milk yield; 3) determine the relationship of EED diagnosis using blood and FTIR predicted blood and milk analytes with somatic cell score and clinical mastitis diagnosis; 4) examine the stability of serum and plasma total calcium following storage at -80°C or after delayed separation from whole blood stored at 4°C; and 5) evaluate quarter and composite milk sampling for detection of subclinical intramammary infections. Both the Nova Vet and TaiDoc blood β-hydroxybutyrate (BHB) meters are acceptable for use in on-farm EED monitoring. Additionally, FTIR predicted milk BHB, predicted blood non-esterified fatty acids (FA), and de novo FA relative percentages are promising indicators of adverse events in early lactation, though their relationship with milk production warrants further exploration. Elevation of blood BHB and FTIR predicted milk BHB and predicted blood non-esterified FA suggest cows undergoing EED have lower somatic cell scores, however the association with clinical mastitis remains unclear. For measuring total calcium, whole blood samples may be stored for 14 days at 4°C in no additive or lithium heparin vacutainer tubes, and serum or plasma may be stored at −80°C for 12 months, all with no effect. And for monitoring subclinical mastitis, due to continued improvement upon mastitis control and reduction in major mastitis pathogens, blanket cut-points may no longer provide the diagnostic usefulness they once did.
dc.subjectDairy cattle
dc.titleMonitoring subclinical metabolic disease in transition dairy cattle
dc.typedissertation or thesis
dc.description.embargo2022-01-17 Science of Philosophy D., Animal Science
dc.contributor.chairMcArt, Jessica Anne Allerton
dc.contributor.committeeMemberNydam, Daryl Van
dc.contributor.committeeMemberBarbano, David Mark
dc.contributor.committeeMemberFelippe, Julia

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