{"id":{"repo_id":"mo-state","oai_identifier":"oai:bearworks.missouristate.edu:theses-1200"},"canonical_url":"https://search.dev.ndltd.org/etd/mo-state/oai:bearworks.missouristate.edu:theses-1200","repository":{"repo_id":"mo-state","name":"Missouri State University","base_url":"https://bearworks.missouristate.edu/do/oai/"},"display":{"title":"The Ontogeny of Thermoregulatory Abilities in Neonatal Cotton Rats and Montane Voles","abstract":"Physiological maturity play a vital role in determining thermoregulatory ability in newborn (neonatal) eutherians. Oxygen consumption (stp mlO₂/h*g⁰·⁶⁷) was measured in open chambers at temperatures 20, 25, 30 and 35°C for cotton rat (Sigmodon hispidus) neonates and at temperatures 25, 30 and 35°C for montane vole (Microtus montanus) neonates to determine the response to cold, and to estimate the thermal neutral zone (TNZ) of each species. TNZ for cotton rats was 33-35°C and for montane voles around 30°C. Since norepinephrine (NE) stimulated BAT metabolism, the effect of NE was measured at thermoneutrality in 2, 4, 6-8 and 12 day old cotton rat neonates, and in 4, 8, 12 and 16 day old montane vole neonates. Two day old cotton rats, and 4 and 8 day old montane voles were unable to raise their metabolism at the lowest temperature. At all ages, NE elevated metabolic rate above control and saline-injected values for both species (repeated measured two-way ANOVA: P<0.001). The response to NE increased with age for both cotton rats and montane voles (repeated measures two-way ANOVA: P<0.001). The number of NE treatments that an animal received did not effect its NE-induced metabolism at day 12 for cotton rats (repeated measures two-way ANOVA: p=0.860), but number of treatments did effect NE-induced metabolism for 16 day old montane voles (repeated measures two-way ANOVA: P<0.001). First NE treatment was lower than third NE treatment (Tukey's test: P<0.022). Adjusted time for peak response to NE treatment showed strong positive correlation with NE-induced metabolic rate. Cotton rats, a precocial species were compared to montane voles, an altricial species. The data show that M. montanus have a slower thermogenic development than S. hispidus.","abstract_html":"Physiological maturity play a vital role in determining thermoregulatory ability in newborn (neonatal) eutherians. Oxygen consumption (stp mlO₂/h*g⁰·⁶⁷) was measured in open chambers at temperatures 20, 25, 30 and 35°C for cotton rat (Sigmodon hispidus) neonates and at temperatures 25, 30 and 35°C for montane vole (Microtus montanus) neonates to determine the response to cold, and to estimate the thermal neutral zone (TNZ) of each species. TNZ for cotton rats was 33-35°C and for montane voles around 30°C. Since norepinephrine (NE) stimulated BAT metabolism, the effect of NE was measured at thermoneutrality in 2, 4, 6-8 and 12 day old cotton rat neonates, and in 4, 8, 12 and 16 day old montane vole neonates. Two day old cotton rats, and 4 and 8 day old montane voles were unable to raise their metabolism at the lowest temperature. At all ages, NE elevated metabolic rate above control and saline-injected values for both species (repeated measured two-way ANOVA: P&lt;0.001). The response to NE increased with age for both cotton rats and montane voles (repeated measures two-way ANOVA: P&lt;0.001). The number of NE treatments that an animal received did not effect its NE-induced metabolism at day 12 for cotton rats (repeated measures two-way ANOVA: p=0.860), but number of treatments did effect NE-induced metabolism for 16 day old montane voles (repeated measures two-way ANOVA: P&lt;0.001). First NE treatment was lower than third NE treatment (Tukey&#x27;s test: P&lt;0.022). Adjusted time for peak response to NE treatment showed strong positive correlation with NE-induced metabolic rate. Cotton rats, a precocial species were compared to montane voles, an altricial species. The data show that M. montanus have a slower thermogenic development than S. hispidus.","abstract_has_math":false,"creators":["Hew, Ginny Y."],"institution":null,"degree_name":"Master of Science in Biology","degree_level":"Masters","degree_discipline":"Biology","degree_department":null,"school":null,"contributors":["Thomas Tomasi"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1997,"date_issued":"1997-07-01T07:00:00Z","date_published":"1997-07-01T07:00:00Z","updated_at":"2026-07-24T03:15:17Z","subjects":["Biology"],"languages":[],"rights":["© Ginny Y Hew"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://bearworks.missouristate.edu/theses/199","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Thomas Tomasi"]},{"key":"dc:creator","label":"Author","values":["Hew, Ginny Y."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"thesis:degree_discipline","label":"Discipline","values":["Biology"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science in Biology"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Biology"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["© Ginny Y Hew"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://bearworks.missouristate.edu/theses/199"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Physiological maturity play a vital role in determining thermoregulatory ability in newborn (neonatal) eutherians. Oxygen consumption (stp mlO₂/h*g⁰·⁶⁷) was measured in open chambers at temperatures 20, 25, 30 and 35°C for cotton rat (Sigmodon hispidus) neonates and at temperatures 25, 30 and 35°C for montane vole (Microtus montanus) neonates to determine the response to cold, and to estimate the thermal neutral zone (TNZ) of each species. TNZ for cotton rats was 33-35°C and for montane voles around 30°C. Since norepinephrine (NE) stimulated BAT metabolism, the effect of NE was measured at thermoneutrality in 2, 4, 6-8 and 12 day old cotton rat neonates, and in 4, 8, 12 and 16 day old montane vole neonates. Two day old cotton rats, and 4 and 8 day old montane voles were unable to raise their metabolism at the lowest temperature. At all ages, NE elevated metabolic rate above control and saline-injected values for both species (repeated measured two-way ANOVA: P<0.001). The response to NE increased with age for both cotton rats and montane voles (repeated measures two-way ANOVA: P<0.001). The number of NE treatments that an animal received did not effect its NE-induced metabolism at day 12 for cotton rats (repeated measures two-way ANOVA: p=0.860), but number of treatments did effect NE-induced metabolism for 16 day old montane voles (repeated measures two-way ANOVA: P<0.001). First NE treatment was lower than third NE treatment (Tukey's test: P<0.022). Adjusted time for peak response to NE treatment showed strong positive correlation with NE-induced metabolic rate. Cotton rats, a precocial species were compared to montane voles, an altricial species. The data show that M. montanus have a slower thermogenic development than S. hispidus."]},{"key":"dc:title","label":"Title","values":["The Ontogeny of Thermoregulatory Abilities in Neonatal Cotton Rats and Montane Voles"]}]}],"canonical_facts":{"dc:contributor":["Thomas Tomasi"],"dc:creator":["Hew, Ginny Y."],"dc:description.abstract":["Physiological maturity play a vital role in determining thermoregulatory ability in newborn (neonatal) eutherians. Oxygen consumption (stp mlO₂/h*g⁰·⁶⁷) was measured in open chambers at temperatures 20, 25, 30 and 35°C for cotton rat (Sigmodon hispidus) neonates and at temperatures 25, 30 and 35°C for montane vole (Microtus montanus) neonates to determine the response to cold, and to estimate the thermal neutral zone (TNZ) of each species. TNZ for cotton rats was 33-35°C and for montane voles around 30°C. Since norepinephrine (NE) stimulated BAT metabolism, the effect of NE was measured at thermoneutrality in 2, 4, 6-8 and 12 day old cotton rat neonates, and in 4, 8, 12 and 16 day old montane vole neonates. Two day old cotton rats, and 4 and 8 day old montane voles were unable to raise their metabolism at the lowest temperature. At all ages, NE elevated metabolic rate above control and saline-injected values for both species (repeated measured two-way ANOVA: P<0.001). The response to NE increased with age for both cotton rats and montane voles (repeated measures two-way ANOVA: P<0.001). The number of NE treatments that an animal received did not effect its NE-induced metabolism at day 12 for cotton rats (repeated measures two-way ANOVA: p=0.860), but number of treatments did effect NE-induced metabolism for 16 day old montane voles (repeated measures two-way ANOVA: P<0.001). First NE treatment was lower than third NE treatment (Tukey's test: P<0.022). Adjusted time for peak response to NE treatment showed strong positive correlation with NE-induced metabolic rate. Cotton rats, a precocial species were compared to montane voles, an altricial species. The data show that M. montanus have a slower thermogenic development than S. hispidus."],"dc:identifier":["https://bearworks.missouristate.edu/theses/199"],"dc:rights":["© Ginny Y Hew"],"dc:subject":["Biology"],"dc:title":["The Ontogeny of Thermoregulatory Abilities in Neonatal Cotton Rats and Montane Voles"],"thesis:degree_discipline":["Biology"],"thesis:degree_level":["Masters"],"thesis:degree_name":["Master of Science in Biology"]},"updated_at":"2026-07-24T03:15:17Z"}