Effects of air temperature, air movement and artificial rain on the heat production of brushtail possums (Trichosurus vulpecula): an exploratory study

Authors: Morris RS, Van den Oord QGW, Holmes CW, Lugton IW, van Wijk EJA
Publication: New Zealand Veterinary Journal, Volume 43, Issue 7, pp 328-332, Dec 1995
Publisher: Taylor and Francis

Animal type: Possum, Wildlife
Subject Terms: Animal welfare, Environment, Husbandry/husbandry procedures, Physiology, Stress
Article class: Scientific Article

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Abstract: Two groups of six mature brushtail possums (Trichosurus vulpeculu) were housed in two respiration chambers, and their heat production, whole body conductance and lower critical temperatures were measured under a variety of simulated weather patterns. The possums were subjected to ambient temperatures of 30, 20 and 3 °C. At 20 and 3 °C, the animals were exposed to near still air and light winds (wind speed 0.8 and 6.7 km/h), both with, and without, simulated rain every 8 hours. The lower critical temperature in near still air lies between 7 and 10 °C. This temperature increases by about 2, 6 and 8 °C respectively for a wind velocity of 6.7 km/h, simulated rain and a combination of the two factors. Weather in New Zealand, especially in the cooler part of the year, will often produce conditions below the lower critical temperature of the thermoneutral zone of possums. This will necessitate significant increases in metabolic rate and hence food consumption or mobilisation of body fat reserves, which if not sustainable will result in the death of possums. Field studies have shown that this is often the case in the wild. It is proposed that this stress may be sufficient to decrease the resistance (especially cell-mediated immunity) of some possums and allow acceleration of the disease process in those infected with Mycobacterium bovis.

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