Energy Expenditure and Maintenance Requirements in Non-Pregnant First-Parity Sows

Five sows, non-pregnant after the first parity (body weight: 174 ± 11 kg), were used to determine energy expenditure (EE) measured as heat production (HP). Sows were fed first 1.0, then 2.0, times the recommended maintenance energy requirement (ME_m) for one week each. Sows received half their daily ration in 16 half-hourly meals, then the remaining half in a large meal followed by an overnight fast in respiration chambers. Sows fed 1.0 ME_m consumed 473 kJ ME/kg^0.75 (22.8 MJ/d) and lost weight (-198 g/d) because HP (24.0 MJ/d) was greater than intake. Sows fed 2.0 ME_m consumed 925 kJ ME/kg^0.75 (44.9 MJ/d) and gained 1292 g/d and HP was 32.3 MJ/d. The respiratory quotient (RQ) of sows fed 2.0 ME_m was greater than one, indicating body fat deposition. The HP when sows were eating repeated small meals (33.6 MJ/d) or a single large meal (29.8 MJ/d) was greater (p < 0.05) than the HP in the following 2 h (25.2 MJ/d). Based upon the recalculation of ME_m using the present data, 506 kJ ME/kg^0.75 is proposed as the ME_m for non-pregnant modern sows.