Energy expenditure and water turnover in hunting dogs in winter conditions.

Hunting with dogs in winter conditions is practised in the Nordic countries. The present study aimed at determining daily energy expenditure (DEE) and body water turnover (BWT) by the doubly labelled water technique in eight hunting dogs (body-weight (BW) range 14-27 kg) working 3 h/d for 3 d (-6 °C) on ground covered with 20-40 cm of loose snow, to provide information on energy and water requirements. The mean distance run during the hunting period was recorded by the global positioning system and averaged 19.4 km/d. DEE increased with increasing BW (P < 0.001) and varied between 7.20 and 16.6 MJ/d (mean 11.0 MJ/d) corresponding to 950-1350 kJ/kg BW(0.75) per d (mean 1170 kJ/kg BW(0.75) per d). The larger dogs tended to run longer than the smaller dogs and therefore spent more energy per kg BW(0.75) but not significantly (P>0.05). DEE values determined were close to the values measured for hunting dogs running for 3 h/d in hot climates, suggesting that climate within the range of the two studies has little impact on energy expenditure per h running activity. Compared with the work of sled dogs per km travelled running on a track, the work performed by the hunting dogs was suggested to be higher when running in a loose snow layer. However, DEE was much lower because sled dogs ran for a longer distance each day. Mean BWT was 217 ml/kg BW(0.75) or 19 ml/kJ metabolisable energy.