Landbouwtijdschrift-revue de l agriculture vol:43 issue:6 pages:1007-1015
An experiment involving 265 Belgian Land-race x Pietrain pigs was conducted to study the effect of lowering the dietary crude protein content upon growth performance, efficiency of feed utilization, carcass characteristics and nitrogen excretion. The control group consisted of 140 animals (70 male castrates and 70 gilts) and received a diet with 18.6 % crude protein in the growing period (26-47 kg) and a diet with 16.5 % crude protein in the finishing period (47-100 kg). The second experimental group comprised 115 animals (57 male castrates and 58 gilts) and was offered a 12.9 % crude protein containing diet during the entire experimental period (26-100 kg). All diets were formulated to contain approximately 8.8 MJ net energy per kg and were fed ad libitum. Daily weight gain and feed conversion were not significantly affected by dietary treatment. The dietary regimen exerted small, but statistically significant effects upon dressing percentage, backfat thickness, carcass length and meat content, however without influencing the commercial value of the carcasses. The experimental group, which was fed the low protein diet, showed approximately 39 % less nitrogen excretion during the entire fattening period.