Dietary energy levels for growing-finishing pigs fed ad libitum. 2. Carcass effects and economic model of the responses

The NRC (1988) recommendations on nutrient standards for growing-finishing pigs assume a corn-based feeding regime. However, the diets used in Western Canada are generally barley-based and consequently are usually lower in digestible energy (DE) and result in reduced growth rate and feed efficiency. Corn and wheat can be included in the diet to raise the DE level, but since this could affect the carcass quality of pigs fed ad libitum, the influence of DE level in relation to carcass quality was measured in two experiments. An economic assessment of the data was also conducted. A total of 432 pigs was used, over the 20-98 kg live weight range. The inclusion of wheat or corn to barley-based diets during the finisher period resulted in reduced carcass quality, and there was also some evidence that increased dietary energy during the grower stage had the same effect.