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dc.contributor.authorChrisp, J. S.
dc.date.accessioned2010-06-21T02:05:37Z
dc.date.available2010-06-21T02:05:37Z
dc.date.issued1986
dc.identifier.urihttps://hdl.handle.net/10182/2094
dc.description.abstractThe kinetics of calcium metabolism in forage fed sheep has been investigated using ⁴⁵Calcium and compartmental analysis, using the SAAM program. Two physiological states, lactation and growth, were studied. During early lactation, calcium metabolism was determined in animals consuming fresh ryegrass-white clover (DMD: 70.6% and Ca: 5.48 mg/g DM) and greenfeed oats (DMD: 68.9% and Ca: 3.79 mg/g DM). The importance of protein status for calcium metabolism in those ewes consuming ryegrass-white clover swards was investigated by protein supplementation. In a further experiment net faecal endogenous loss of calcium was estimated in growing sheep consuming fresh or conserved forages, both contrasting in digestibility (DMD: 72.7 v 57.1%, respectively) and calcium content (Ca: 12.1 v 6.41 mg/g DM, respectively). Trial one, undertaken during the first nine weeks of lactation, protein supplementation (100 g/d/head of protected casein per os.) increased milk production by up to 24%, gastrointestinal calcium absorption (mean ± s.e.m. 51.8 ± 15.3 v 75.4 ± 4.4 mg/d/kg LW for control and protein groups, respectively) and skeletal calcium accretion (41.7 ± 3.8 v 48.6 ± 5.3 mg/d/kg LW). Skeletal resorption was decreased (66.9 ± 14.4 v 59.9 ± 8.6 mg/d/kg LW) and the overall calcium balance increased (-25.2 ± 17.2 v -11.5 ± 4.2 mg/d/kg LW). In trial two, unprotected casein was infused (100 g/d/head abomasally) and milk production was balanced between control and supplemented groups offered ryegrass-white clover herbage (DMD: 78.1% and Ca: 6.47 mg/g DM). Protein supplementation significantly improved nitrogen balance in both trials and changed calcium parameters, similar in both, although not significantly. Possible reasons for this are discussed. Calcium availability from oats was lower than that from ryegrass-white clover (17 v 19%, respectively); this was unexpected because of the lower calcium content of the oats. All availability values obtained were much lower than current ARC's. Net faecal endogenous loss varied with dry matter intake (19.6 to 53.6 mg/d/kg LW) in wethers. When data from all three trials were combined, the best predictor of endogenous loss was faecal calcium output. Factors affecting this loss are discussed.en
dc.language.isoenen
dc.publisherLincoln College, University of Canterburyen
dc.rights.urihttps://researcharchive.lincoln.ac.nz/page/rights
dc.subjectcalciumen
dc.subjectcompartmental analysisen
dc.subjectendogenous lossen
dc.subjectforageen
dc.subjectgrowthen
dc.subjectherbagesen
dc.subjectkineticsen
dc.subjectlactationen
dc.subjectprotein supplementationen
dc.subjectsheepen
dc.titleKinetic aspects of calcium metabolism in forage fed sheepen
dc.typeThesisen
thesis.degree.grantorUniversity of Canterburyen
thesis.degree.levelDoctoralen
thesis.degree.nameDoctor of Philosophyen
lu.thesis.supervisorSykes, A. R.
lu.contributor.unitDepartment of Agricultural Sciencesen
dc.rights.accessRightsDigital thesis can be viewed by current staff and students of Lincoln University only. Print copy available for reading in Lincoln University Library. May be available through inter-library loan.en
dc.subject.anzsrc070204 Animal Nutritionen
dc.subject.anzsrc070202 Animal Growth and Developmenten


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