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dc.contributor.authorMcArt, Jessicaen_US
dc.identifier.otherbibid: 8267309
dc.description.abstractThe ability of dairy cattle to adapt to the natural change of energy balance in early lactation is an important aspect of the transition period, as the demands for milk production cannot be met by feed intake alone. Cattle unable to adequately transition from late gestation to early lactation are at a higher risk for subclinical ketosis (SCK), an excess of circulating ketone bodies without clinical signs of hyperketonemia. Cows with SCK are at an increased risk of postpartum diseases such as displaced abomasum and metritis, and SCK has been found to decrease milk yield in early lactation and may adversely affect reproduction. The objectives herein were to: 1) describe the epidemiology of SCK in cows diagnosed with SCK in early lactation; 2) determine important dry and parturient period risk factors of hyperketonemia development; 3) determine the effect of oral administration of propylene glycol in cows diagnosed with SCK on disease development, removal from the herd, reproduction, and milk production; and 4) estimate the cost per case of SCK and evaluate different on-farm testing and treatment strategies based on herd SCK incidence. Peak incidence and prevalence of SCK was found to occur at 5 days in milk (DIM) with a median time to resolution of 5 days. Cows developing SCK from 3 to 7 DIM were more likely to suffer from negative disease and production outcomes than cows that developed SCK from 8 to 16 DIM. Treatment of SCK positive cows with propylene glycol decreased disease incidence, improved reproduction, and enhanced milk production over non-treated control cows. Risk factors associated with development of hyperketonemia included advanced parity, high prepartum non-esterified fatty acid concentrations, and calving difficulty. The cost per case of SCK in the first 30 DIM was estimated at $67. Testing of fresh cows 2 days per week from 3 through 9 DIM and treatment of SCK positive cows with propylene glycol was found to be the most cost-effective treatment in herds with SCK incidences between 15 and 50%; above 50% blanket treatment of all fresh cows with propylene glycol was more economically beneficial.en_US
dc.subjectsubclinical ketosisen_US
dc.subjectpropylene glycolen_US
dc.subjectdairy cowen_US
dc.titleThe Epidemiology, Economics, And Treatment Of Subclinical Ketosis In Early Lactation Dairy Cattleen_US
dc.typedissertation or thesisen_US Medicine Universityen_US of Philosophy D., Veterinary Medicine
dc.contributor.chairNydam, Daryl Vanen_US
dc.contributor.committeeMemberOverton, Thomas Ren_US
dc.contributor.committeeMemberGuard III, Charles Len_US
dc.contributor.committeeMemberFlaminio, Maria Julia Bevilaqua Felippeen_US
dc.contributor.committeeMemberGrohn, Yrjo Tapioen_US

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