Influence of ambient temperature and feed intake level on growth performance of growingfinishing pigs

An experiment using 360 growing-finishing pigs was conducted to determine the effect of ambient temperature (24 vs 17 °C) and the level of feeding on the pig growth performance. Pigs were fed ad libitum or restricted to 90 or 80 per cent of ad libitum intake. Thus, 6 treatments were compared (2 temperatures x 3 levels of feeding).In ad libitum feeding, average daily gain (ADG) was globally 8 % higher (P < 0.001) at 17 than at 24 °C; feed intake was also increased by the lower temperature (+180 g /d, P < 0.001). However, feed conversion ratio (FCR) and the percentage of muscle in the carcass were similar at both temperatures.At both temperatures, ADG increased linearly (P < 0.001) with the increase in feed intake. At both 24 and 17 °C, one gram of extra feed intake was associated with a 0.50 g increase in ADG. At similar feed intakes, ADG was 40 g lower (P < 0.001) at 17 than at 24 °C, this can be overcome by supplying extra feed (80 g/d). FCR increased by 0.016 unit/°C (P < 0.01) between 24 and 17 °C.At both temperatures, the percentage of muscle in the carcass increased (P < 0.001) with a decrease in feeding level.Moreover, at similar feed intakes, it was higher (P < 0.05) at 17 than at 24 °C.