Rates of heat and water loss in female mink (Mustela vison) measured by direct calorimetry.

The energy expenditure (EE) of adult female mink was studied by continuous 24-hr measurement of rates of total heat loss (THL) in a controlled environment using a 24 m3 calorimeter allowing separate on-line determination of sensitive (SHL) and evaporative (EHL) heat loss within the range of 20-200 W (72-720 kJ/hr). In four adult female mink (scanblack colour mutant), studied in transparent cages and given free access to feline food pellets and water, the mean 24-hr energy expenditure (= THL) under controlled experimental conditions was 8.9 W/kg (range: 5.5-13.1 W/kg) at 18 degrees C and 5.8 W/kg (range: 4.3-9.5 W/kg) at 24 degrees C. The results are in agreement with the data reported in the literature on the metabolic rate of adult farm-raised mink, calculated from rates of oxygen uptake under controlled experimental conditions, and with the energy requirement for maintenance, 586 kJ/kg/day (6.8 W/kg) recommended by the NRC. Under the experimental conditions of the present study the mean rate of total evaporative water loss (TEWL) amounted to 3.7 g/kg/hr at 18 degrees C and 5.5 g/kg/hr at 24 degrees C. The contributions of SHL and EHL to 24-hr THL in female mink were inversely related and markedly dependent on chamber temperature. When corrected for evaporated urinary and faecal water, SHL and EHL amounted to 76 and 24% of THL at 18 degrees C, but at 24 degrees C the corresponding values were 41 and 59%.(ABSTRACT TRUNCATED AT 250 WORDS)