EFFICIENCY OF CONVERSION OF PROTEIN, ENERGY AND CARBON IN PIGS RESTRICTED LATE IN THE FATTENING PERIOD

Abstract

Three treatments, HB — a high level of a basal ration, LB — a low level of the basal ration, and HP — a low level of a high-protein ration, were tested in each of two experiments with pigs at 65 kilograms liveweight. Carbon-nitrogen balance methods were used to compare the treatments in the first experiment with 6 pigs while weight gain and carcass analysis were used with 24 pigs in the second experiment.In Experiment 1, the LB group, which was restricted to approximately 1600 grams of feed per day, retained the same percentage of ingested protein but deposited a lower percentage of the digestible calories as fat. The HP group grew at the same rate as the LB group and retained more total nitrogen but this represented a lower percentage of the ingested nitrogen. There was little difference in fat storage of the HP and the LB groups. Carcass measurements and analysis of carcasses in Experiment 2 confirmed the findings in Experiment 1. The HP group required an average of 73 days to reach 87 kilograms in body weight, compared to 66 days for the LB group and 27 days for the HB group. Restricted feeding of the basal ration increased the protein in the carcasses by 7.0 per cent and decreased the fat by 3.9 per cent. A restricted intake of the high protein ration resulted in a further 3.1 per cent increase in carcass protein and a 1.8 per cent decrease in fat.