The efficiency of utilization of the energy of food by weaned pigs of the Large White breed was measured. Three diets based on maize (40–60%) had a metabolizable energy of 75·8±1·2% of the gross energy, and 78·2 ±3·4% of the metabolizable energy was present as net energy.
The maintenance requirement of metabolizable energy of pigs weighing 14·3 ± 2·1 kg was 143·6 kcal/kg°0·75/24 h (601 kJ/kg0·75/24 h).
The energy cost per g protein and fat synthesized by piglets was estimated to be 7·43 and 12·05 kcal (31·1 and 50·4 kJ) metabolizable energy, respectively.
Equations for calculation of metabolizable energy (Yl, kcal) and of the net energy (Y2, kcal), based on digested nutrients, were:
Y1 = 4·64×1 + 9·12×2 + 4·25×3'CV = ± 1·2%,
Y2 = 3·84×1 + 7·09×2 + 3·28×3'CV = ± 1·4%,
where X1 = g protein digested, X2 = g fat digested, X3= g carbohydrate digested (crude fibre × N-free extracts).