Nutritional and endocrine aspects of the lactation cycle of Holstein and Jersey cows: nutrient balances, response to supplemental dietary fat, rib composition and rib histology

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dc.contributor.authorBallantine, Holly Tayloren
dc.contributor.committeechairHerbein, Joseph H. Jr.en
dc.contributor.committeememberAkers, Robert Michaelen
dc.contributor.committeememberDenbow, D. Michaelen
dc.contributor.committeememberMcGilliard, Michaelen
dc.contributor.committeememberPolan, Carl E.en
dc.contributor.committeememberSteeves, Harrison R. IIIen
dc.contributor.departmentAnimal Scienceen
dc.date.accessioned2015-07-28T19:21:16Zen
dc.date.available2015-07-28T19:21:16Zen
dc.date.issued1989en
dc.description.abstractEight mature Holstein and Jersey cows beginning their third or later lactation were used throughout this study to evaluate various aspects of the lactation cycle. The lactation (control) diet consisted of 28.8% corn silage, 22.4% alfalfa haylage, and 48.8% concentrate dry matter. Breeds responded differently to the stress of calving. Jerseys had higher plasma somatotropin on day after calving, but Holsteins had higher glucose on day of and day after calving. Plasma parathyroid hormone did not differ between breeds, but Jerseys had higher 1,25-dihydroxyvitamin D₃ than Holsteins on both days after calving. Plasma total calcium and ionized calcium concentrations were lower for Jerseys on both days. Holsteins and Jerseys had similar concentrations of hormones and calcium at 4 and 8 wk. Ionized calcium as a percent of total calcium was elevated at calving, as compared to other times in the lactation cycle, in both breeds. From 9 to 21 wk, 4 of 8 Holsteins and 4 of 8 Jerseys were fed a diet supplemented with tallow. Holsteins fed tallow had lower somatotropin than Holsteins fed control diet at 14 and 18 wk. Plasma glucose, parathyroid hormone, and 1,25-dihydroxyvitamin D₃ were similar between tallow- and control-fed cows in both breeds. Plasma total calcium and ionized calcium were higher at 20 wk for Holsteins and Jerseys fed tallow. Dry matter intake was not influenced by diet in either breed. However, Holsteins, but not Jerseys, fed tallow produced more milk and higher body weights than Holsteins fed the control diet. Balance trials results indicated dietary tallow addition increased energy intake, energy digestibility, and metabolizable energy, but it decreased partial efficiency of metabolizable energy utilization for lactation. Although digestibility of calcium and magnesium was unchanged, tallow-fed cows were in greater positive calcium and magnesium balance than control-fed cows. Stage of lactation had little effect on specific gravity, shear stress, percent mineral, and histological measurements of biopsied rib samples. However, Jersey rib had higher specific gravity than Holstein rib. All cows had similar bone histological features throughout lactation.en
dc.description.degreePh. D.en
dc.format.extentxiv, 197 leavesen
dc.format.mimetypeapplication/pdfen
dc.identifier.urihttp://hdl.handle.net/10919/54765en
dc.language.isoen_USen
dc.publisherVirginia Polytechnic Institute and State Universityen
dc.relation.isformatofOCLC# 21268851en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V856 1989.B344en
dc.subject.lcshHolstein-Friesian cattleen
dc.subject.lcshJersey cattleen
dc.subject.lcshDairy cattleen
dc.titleNutritional and endocrine aspects of the lactation cycle of Holstein and Jersey cows: nutrient balances, response to supplemental dietary fat, rib composition and rib histologyen
dc.typeDissertationen
dc.type.dcmitypeTexten
thesis.degree.disciplineAnimal Scienceen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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