Body composition, metabolic rate and utilization of milk nutrients in suckling piglets.

The oxygen (O2) consumption, carbon dioxide (CO2) production, heat production (HP) and milk nutrient intake of 22 litters of suckling piglets were recorded every 4 days from the day after birth to weaning at 22 days of age. At weaning, 147 representative piglets of these litters were slaughtered to measure their chemical composition and to calculate the energy and nutrient balance of individual piglets and litters between birth and weaning. O2 consumption, CO2 production and HP were constant over the suckling period when expressed per kg of body weight0.68 (BW0.68); O2 consumption and HP averaged 34.4 liters and 168 kcal per kg of BW0.68 and per day, respectively. The respiratory quotient (RQ) (CO2/O2) was 0.84. Average daily gain between birth and weaning (ADG) ranged from 35 to 285 g (mean: 186 g). Dry matter, fat and energy contents of piglets at weaning were positively correlated with ADG while protein and ash contents were negatively correlated with ADG. The daily amounts of protein, fat, ash and energy deposited were linearly related to ADG, so that the chemical composition of additional gain was constant: 410, 141, 197 and 28 mg/g and 2,960 cal/g for dry matter, protein, fat, ash and energy, respectively. The deposition of 1 g of protein or fat was associated with 5.20 or 1.17 g of weight gain, respectively. Finally, 55% of the energy and 85% of the nitrogen supplied by milk were retained in piglet weight gain.