Sensible heat loss from Muskoxen (Ovibos moschatus) feeding in winter: small calves are not at a thermal disadvantage compared with adult cows
Muskoxen (Ovibos moschatus) are large (>200 kg adult body mass) mammalian herbivores that overwinter in the polar regions. Calves are around one-third the body mass of mature females and may be expected to suffer greater thermal stresses in winter compared with adults because the ratio of surface...
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ftunivwollongong:oai:ro.uow.edu.au:scipapers-1868 2023-05-15T17:54:11+02:00 Sensible heat loss from Muskoxen (Ovibos moschatus) feeding in winter: small calves are not at a thermal disadvantage compared with adult cows Munn, Adam J Barboza, Perry S Dehn, Jon 2009-01-01T08:00:00Z application/pdf https://ro.uow.edu.au/scipapers/829 https://ro.uow.edu.au/cgi/viewcontent.cgi?article=1868&context=scipapers unknown Research Online https://ro.uow.edu.au/scipapers/829 https://ro.uow.edu.au/cgi/viewcontent.cgi?article=1868&context=scipapers Faculty of Science - Papers (Archive) Life Sciences Physical Sciences and Mathematics Social and Behavioral Sciences article 2009 ftunivwollongong 2020-02-25T11:00:11Z Muskoxen (Ovibos moschatus) are large (>200 kg adult body mass) mammalian herbivores that overwinter in the polar regions. Calves are around one-third the body mass of mature females and may be expected to suffer greater thermal stresses in winter compared with adults because the ratio of surface area to volume (SA : vol) is much greater for calves than for adults. We found that during feeding bouts, when animals are fully exposed to environmental conditions, calves did lose sensible (dry) heat more readily than adults (W m(-2)) in still air conditions. However, calves and cows lost less than 2%-6% of their estimated daily digestible energy intake as conductive, convective, and radiant heat losses accumulated during feeding bouts. More important, calves did not lose relatively more heat than larger adults in terms of sensible losses as part of their daily energy intake. Coat surface temperatures were only 2 degrees-5 degrees C above ambient even when air temperature fell to -40 degrees C. Body temperatures recorded deep within the ear canal near the tympanum fluctuated in both cows and calves. Muskoxen combine peripheral heterothermy and an exceptional winter coat to minimize sensible heat loss in winter. These mechanisms appear to have circumvented some of the thermal problems normally associated with a high SA : vol ratio in calves, which reflects the strong selection to conserve energy in winter. Article in Journal/Newspaper ovibos moschatus University of Wollongong, Australia: Research Online |
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Open Polar |
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University of Wollongong, Australia: Research Online |
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ftunivwollongong |
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topic |
Life Sciences Physical Sciences and Mathematics Social and Behavioral Sciences |
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Life Sciences Physical Sciences and Mathematics Social and Behavioral Sciences Munn, Adam J Barboza, Perry S Dehn, Jon Sensible heat loss from Muskoxen (Ovibos moschatus) feeding in winter: small calves are not at a thermal disadvantage compared with adult cows |
topic_facet |
Life Sciences Physical Sciences and Mathematics Social and Behavioral Sciences |
description |
Muskoxen (Ovibos moschatus) are large (>200 kg adult body mass) mammalian herbivores that overwinter in the polar regions. Calves are around one-third the body mass of mature females and may be expected to suffer greater thermal stresses in winter compared with adults because the ratio of surface area to volume (SA : vol) is much greater for calves than for adults. We found that during feeding bouts, when animals are fully exposed to environmental conditions, calves did lose sensible (dry) heat more readily than adults (W m(-2)) in still air conditions. However, calves and cows lost less than 2%-6% of their estimated daily digestible energy intake as conductive, convective, and radiant heat losses accumulated during feeding bouts. More important, calves did not lose relatively more heat than larger adults in terms of sensible losses as part of their daily energy intake. Coat surface temperatures were only 2 degrees-5 degrees C above ambient even when air temperature fell to -40 degrees C. Body temperatures recorded deep within the ear canal near the tympanum fluctuated in both cows and calves. Muskoxen combine peripheral heterothermy and an exceptional winter coat to minimize sensible heat loss in winter. These mechanisms appear to have circumvented some of the thermal problems normally associated with a high SA : vol ratio in calves, which reflects the strong selection to conserve energy in winter. |
format |
Article in Journal/Newspaper |
author |
Munn, Adam J Barboza, Perry S Dehn, Jon |
author_facet |
Munn, Adam J Barboza, Perry S Dehn, Jon |
author_sort |
Munn, Adam J |
title |
Sensible heat loss from Muskoxen (Ovibos moschatus) feeding in winter: small calves are not at a thermal disadvantage compared with adult cows |
title_short |
Sensible heat loss from Muskoxen (Ovibos moschatus) feeding in winter: small calves are not at a thermal disadvantage compared with adult cows |
title_full |
Sensible heat loss from Muskoxen (Ovibos moschatus) feeding in winter: small calves are not at a thermal disadvantage compared with adult cows |
title_fullStr |
Sensible heat loss from Muskoxen (Ovibos moschatus) feeding in winter: small calves are not at a thermal disadvantage compared with adult cows |
title_full_unstemmed |
Sensible heat loss from Muskoxen (Ovibos moschatus) feeding in winter: small calves are not at a thermal disadvantage compared with adult cows |
title_sort |
sensible heat loss from muskoxen (ovibos moschatus) feeding in winter: small calves are not at a thermal disadvantage compared with adult cows |
publisher |
Research Online |
publishDate |
2009 |
url |
https://ro.uow.edu.au/scipapers/829 https://ro.uow.edu.au/cgi/viewcontent.cgi?article=1868&context=scipapers |
genre |
ovibos moschatus |
genre_facet |
ovibos moschatus |
op_source |
Faculty of Science - Papers (Archive) |
op_relation |
https://ro.uow.edu.au/scipapers/829 https://ro.uow.edu.au/cgi/viewcontent.cgi?article=1868&context=scipapers |
_version_ |
1766161914133479424 |