Heat production (HP) in the fed state
was measured and feces and urine were collected in the
balance trial. The total HP increased (P < 0.01) with
increasing feeding levels. Fasting HP increased (P <
0.01) as previous feeding level increased and was less
(P = 0.012) in finishing pigs than growing pigs if calculated
per kilogram BW0.6 per day. When using an exponential
regression analysis, ME requirements for maintenance
were estimated at 973 and 921 kJ/kg BW0.6·d–1
and NE requirements for maintenance were estimated
at 758 and 732 kJ/kg BW0.6·d–1 for growing and finishing
pigs, respectively. The efficiencies of using ME for
growth and for maintenance were estimated at 66 and
78.7% for growing and finishing pigs, respectively. It is
concluded that exponential regression between HP and a
wide range of ME intake may be used as a new method
to determine the NE requirement for maintenance.