The prediction of body composition in bacon pigs from measurements of feed intake and live-weight gain

Abstract

SUMMARY Predictions of body composition have been made in 24 baconweight pigs of widely differing fatness, using feed intake and live-weight gain data. Measurements of feed intake and live weight were made every 7 days throughout the growing period from 25 to 90 kg. After each pig was killed at about 90 kg, one carcass side was physically dissected and the whole empty body was chemically analysed. Multiple regression equations were then computed with the dependent variables being the weights of the physically dissectible and the chemical components. The independent variables were initial live weight, energy intake above maintenance, and live-weight gain. The residual standard deviations of the regressions as a percentage of the mean weights of the dependent variables were for body lipid, 5·6%, fat-free mass, 3·3%, dissectible fat, 6·1 % and dissectible lean, 4·9 %. The predictions seem at least as good as can be achieved by more sophisticated techniques. Analysis of the data allowed the efficiency of utilization of energy for protein and lipid deposition to be calculated, and an estimate of the energy costs of maintenance to be made.