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dc.contributor.authorWichtel, Jeffrey Jay
dc.date.accessioned2011-12-16T02:40:45Z
dc.date.available2011-12-16T02:40:45Z
dc.date.issued1995
dc.identifier.urihttp://hdl.handle.net/10179/2958
dc.description.abstractSelenium (Se) deficiency has been recognised for over 30 years as a factor which limits production in grazing livestock. Diseases associated with selenium deficiency in New Zealand include nutritional myodegeneration (white muscle disease) of lambs,calves and goats, infertility of ewes and ill-thrift of sheep and cattle. Although white muscle disease is the most recognisable manifestation of deficiency, sub-clinical deficiencies are more common. Such deficiencies result in decreased growth rate, milk production and lambing percentage (Grace, 1994). The wide distribution of soils that are deficient in selenium (Watkinson, 1983) means that Se deficiency and its amelioration has considerable economic importance to New Zealand. Also of importance is lost revenue due to inappropriate supplementation leading to unnecessary expense and, on occasion, losses due to toxicity. There is a need to avoid excessive treatment to minimise the risk of selenium concentrations in ruminant liver and kidney tissue exceeding the acceptable concentration for human consumption. The development of reference ranges for the prevention of ill-thrift and myodegeneration in young stock has been the primary aim of selenium research in New Zealand to date. This has left many other aspects of selenium and its role in grazing ruminants to be elucidated. For example, there are few data on which to base reference ranges for adult dairy cattle. This lack of information was an important impetus for the studies presented in this thesis.en_US
dc.language.isoenen_US
dc.publisherMassey Universityen_US
dc.rightsThe Authoren_US
dc.subjectSelenium in animal nutritionen_US
dc.subjectDeficiency diseases in domestic animalsen_US
dc.subjectRuminantsen_US
dc.subjectFeeding and feedsen_US
dc.subjectPhysiological effectsen_US
dc.titleThe role of selenium in grazing ruminants : a thesis presented in partial fulfilment of the requirement for the degree of Doctor of Philosophy at Massey Universityen_US
dc.typeThesisen_US
thesis.degree.disciplineVeterinary Clinical Science
thesis.degree.grantorMassey University
thesis.degree.levelDoctoral
thesis.degree.levelDoctoralen
thesis.degree.nameDoctor of Philosophy (Ph.D.)


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