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dc.contributor.advisorWobeser, Gary A.en_US
dc.creatorSoos, Catherineen_US
dc.date.accessioned2004-11-30T16:14:15Zen_US
dc.date.accessioned2013-01-04T05:09:29Z
dc.date.available2004-12-01T08:00:00Zen_US
dc.date.available2013-01-04T05:09:29Z
dc.date.created2004-11en_US
dc.date.issued2004-11-18en_US
dc.date.submittedNovember 2004en_US
dc.identifier.urihttp://hdl.handle.net/10388/etd-11302004-161415en_US
dc.description.abstractThis study investigated factors associated with two mortality events: avian botulism in waterfowl and mortality associated with hatching asynchrony in prefledgling Franklin’s gulls (Larus pipixcan). The initial focus of my research was on the spatiotemporal relationship between mortality of Franklin’s gulls and the onset of botulism outbreaks in waterfowl, and the suitability of gull carcasses for proliferation and toxigenesis of Clostridium botulinum. From 1999 to 2001, dead hatch-year Franklin’s gulls were by far the most abundant carcasses, and the only source of toxin-laden maggots found on transects prior to the occurrence of avian botulism in waterfowl. Nest density was a significant predictor of hatch-year gull carcass density. High density of toxic material from gull carcasses prior to the onset of botulism in waterfowl coincided with high densities of susceptible birds; hence, mortality of Franklin’s gulls has the potential to be a major initiating factor for botulism outbreaks at Eyebrow Lake, Saskatchewan. The causes of gull mortality were conditions or diseases associated with starvation, stress, or immunosuppression, and most mortality occurred in third-hatched chicks. To separate effects of laying order from effects of hatching asynchrony on prefledgling survival, a cross-fostering experiment was conducted to create clutches containing asynchronously hatching eggs of the same laying order, and of similar egg mass, egg volume, and female quality. Hatching order, independent of laying order, significantly affected survival to fledging, whereas laying order had no observable effect, indicating that intraclutch variation in egg quality does not predetermine the fate of prefledglings, and may be less important than hatching asynchrony for survival of prefledgling Franklin’s gulls. Relationships among hatching asynchrony, laying order, mass, corticosterone, immune function, growth, and survival at two stages of development were complex. Hatching asynchrony significantly affected early and late prefledgling survival, and was directly or indirectly associated with mass, corticosterone level, and cell-mediated immune responses at early and later stages of development. Both hatching asynchrony and mass appeared to play key roles in mediating life history trade-offs among cell-mediated immune function, growth, and survival. In contrast to cell-mediated immune responses, primary humoral immune response was not directly affected by hatching order or mass, nor was it associated with survival to fledging. Rather, it was associated with laying order, neonatal testosterone, corticosterone at 2 weeks, growth of leg length, and clutch initiation date, illustrating the importance of examining more than one branch of the immune system in studies of life history trade-offs. This study is a step toward using a multipronged and multidisciplinary approach to demonstrate interactions and trade-offs among life history traits, the physiological mechanisms that produce these relationships, and how these relationships may change depending on stage of development.en_US
dc.language.isoen_USen_US
dc.subjecttestosteroneen_US
dc.subjectconditionen_US
dc.subjectegg qualityen_US
dc.subjectlaying orderen_US
dc.subjecthatching asynchronyen_US
dc.subjectlife history trade-offsen_US
dc.subjectstressen_US
dc.subjectimmune functionen_US
dc.subjectcorticosteroneen_US
dc.subjectLarus pipixcanen_US
dc.subjectcarcass densityen_US
dc.subjectavian botulismen_US
dc.subjectClostridium botulinum type Cen_US
dc.subjectwaterfowlen_US
dc.titleLinks between avian botulism outbreaks in waterfowl, hatching asynchrony, and life history trade-offs of prefledgling Franklin's gulls (larus pipixcan)en_US
thesis.degree.departmentVeterinary Pathologyen_US
thesis.degree.disciplineVeterinary Pathologyen_US
thesis.degree.grantorUniversity of Saskatchewanen_US
thesis.degree.levelDoctoralen_US
thesis.degree.nameDoctor of Philosophy (Ph.D.)en_US
dc.type.materialtexten_US
dc.type.genreThesisen_US
dc.contributor.committeeMemberSamuel, Michael D.en_US
dc.contributor.committeeMemberLeighton, Frederick A.en_US
dc.contributor.committeeMemberJackson, Marion L.en_US
dc.contributor.committeeMemberClark, Robert G.en_US
dc.contributor.committeeMemberBortolotti, Gary R.en_US
dc.contributor.committeeMemberBollinger, Trent K.en_US


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