Seasonal energy expenditures and thermoregulatory responses of moose

• Published in: Canadian Journal of Zoology
• Main Authors: Renecker, Lyle A., Hudson, Robert J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1986
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Alces alces
• Online Access: http://dx.doi.org/10.1139/z86-052; http://www.nrcresearchpress.com/doi/pdf/10.1139/z86-052

Metabolic rates and thermoregulatory responses were studied in adult moose (Alces alces) exposed to various ambient temperatures during winter and summer. Resting energy expenditures followed a marked annual cycle with a maximum (940 kJ kg body weight −0.75 d −1 ) during spring – early summer and minimum (430 kJ kg body weight −0.75 d −1 ) during winter. The heat increment of feeding associated with a pelleted ration was 6–9 kJ kg body weight −0.75 h −1 . The energy cost of standing was 4.2 kJ kg body weight −0.75 h −1 , an increment of 25% over the lying posture. Although piloerection was observed between −25 and −30 °C, metabolic rates did not increase. In contrast to their cold tolerance, moose were easily heat stressed. During winter, moose increased respiration rates when ambient temperatures rose above −5 °C. Resistance to heat load was greater for standing moose during summer; respiration rate increased above 14 °C and open-mouthed panting began at 20 °C. Energy expenditure and heart rate followed a similar rise with increasing ambient temperature.