Energy values in pig nutrition:II. The prediction of energy values from dietary chemical analysis

Abstract

SUMMARYEighteen individual feedstuffs and 19 mixed diets were used in a study attempted to relate determined energy values to various chemically determined measures. For cereals the level of fibre could be used to predict digestible and metabolizable energy (DE and ME). In the case of DE the relationships with crude fibre and modified acid detergent fibre (MADF) based on 14 feeds were:DE (kcal/kg D.M.) = 4179–86 MADF (%):r=–0·96; P < 0·01,DE (kcal/kg D.M.) = 4228–140 x crude fibre (%):r=–0·97;P< 0·01.For all feeds the following equations gave the best prediction of energy values from dietary analysis (on the basis of correlation coefficients and residual standard deviations):DE (kcal/kg D.M.) = 109·9 x crude protein (%) + 149·3 x acid ether extract (%) + 90·1 x nitrogen-free extract (%)–5030: R = 0·95; P < 0.01.ME (kcal/kg D.M.) = 99·5 x crude protein (%) + 144·7 x acid ether extract (%) + 87·8 x nitrogen-free extract (%)–4795: R = 0·94; P < 0·01.Digestible nutrients were closely related to DE and ME, e.g.DE (kcal/kg D.M.) = 52·9 x digestible crude protein (%) + 108·3 x digestible ether extract (%) + 39·4 x digestible crude fibre (%) + 39·9 x digestible nitrogen-free extract (%) + 183·7: R = 0·99; P < 0·01.