Effect of housing and temperature on metabolic rate of pregnant sows

Abstract

Twelve pregnant sows, 35 to 52 days pregnant initially and 89 to 103 days pregnant at the end of the experiment, were used to study the effect of ambient temperature on metabolic rate. Six sows were group-housed in two groups of three sows per group in one calorimeter and six sows were tethered individually in another calorimeter. Temperatures were changed by 3°C every 3 days in a stepwise fashion from 20 to 8°C and from 8 to 20°C. Sows were given a constant amount of food, which gave 540 kJ metabolic energy per kg live weight^0·75per day and which covered estimated needs that were proportionately 0·20 above maintenance.Average daily live-weight gain was 531 g for the group-housed sows and 402 g for those housed individually. Heat loss increased below 14°C in group-housed and below 20°C in individually-housed sows. Extra daily thermoregulatory demand was 7·5 kJ/°C in group- and 13·7 kJ/°C in individually-housed sows.