Carbon dioxide production, energy expenditure and 14CO2 recovery in sows given a single meal of half of daily intake. After a 12 h food-deprivation, intravenous NaH14CO3 solutions were infused for 2 h prior to feeding and for 6 h after feeding. CO2 production and energy expenditure were calculated each minute and breath 14CO2 was collected in 30 min periods. Data are means of n = 5 sows at each time point. : Energy expenditure. : CO2 production. ●: 14CO2 recovery.