Digestible energy content of cereals and wheat by-products for growing pigs

ABSTRACT 1. The digestible energy content of eight samples of barley, sorghum, wheat, weather-damaged wheat and wheat by-products produced from different regions of eastern Australia was determined using growing pigs. The relationships between physical and chemical composition and digestible energy content of the meals were studied. 2. The mean and range in digestible energy (MJ/kg, air-dry basis) were, respectively: barleys 12·7 (12·4 to 13·0), sorghums 14·4 (14·1 to 14·9), wheats 14·4 (14·0 to 15·0), weather-damaged wheats 14·1 (12·9 to 14·9) and wheat by-products 12·4 (10·9 to 14·1). 3. All possible regressions of digestible energy content against density, gross energy and proximate analyses of the meals were screened to select useful relationships. These screens indicated that, with the exception of wheat by-products, the majority of variation in digestible energy was due to gross energy and fibre. For wheat by-products, a combination of density and fibre accounted for most of the variation. 4. Prediction equations had the most application to weather-damaged wheats, wheat by-products and a combination of all samples. 5. There was no indication that neutral-detegent fibre was superior to crude fibre as a predictor of digestible energy in cereals for pigs.