The partial replacement of soybean meal by amino acids in pig rations based on wheat and sorghum

Abstract

In five experiments involving 104 pigs, rations consisting of grain and 15 per cent soyhean meal as the major components were compared with rations of grain plus 7.5 per cent soybean meal in combination with lysine and methionine. In three of the experiments, comparisons were also made between wheat and sorghum as basal grains. The results showed a response in growth rate and feed efficiency to the addition of 0.24 per cent L-lysine HCl.2H2O either with or without 0.20 per cent DL-methionine to rations of grain plus 7.5 per cent soybean meal. From weaning to 45 kg body weight the growth rates of pigs fed these amino acidsupplemented rations were consistently less than those obtained with pigs fed the grain plus 15 per cent soybean meal rations, although not always significantly so. From 45 kg to the final slaughter weight of approximately 90 kg, only in one experiment were the results obtained with the rations containing 7.5 per cent soybean meal plus amino acids significantly less than those obtained with the 15 per cent soybean meal rations. Where comparisons were made between wheat and sorghum, the wheat-based rations consistently produced better growth rates and feed efficiencies, and in one experiment better carcase measurements.