GROWTH AND DIGESTIBILITY STUDIES WITH GROWING–FINISHING PIGS RECEIVING WHOLE BARLEY OR GROUND BARLEY BY VARIOUS FEEDING METHODS

Abstract

Two growth trials and one digestibility trial with growing–finishing pigs are reported. In each growth trial, three groups of six barrows and three groups of six gilts were placed on each of the four dietary treatments of barley plus 15% soybean meal from approx. 23 kg body weight to approx. 84 kg body weight. The four treatments consisted of providing barley whole or ground, with the concentrates either mixed with the barley or supplied 6 h after the meal of barley. The feed allowance was slightly greater in the second trial than in the first. In the digestibility trial there were two sources of barley, each presented in three forms: whole, rehydrated acid-preserved whole, and ground, all mixed with the concentrates. Each diet was supplied at a restricted level or ad libitum to barrows at 28.9 kg and 57.0 kg mean body weight. In neither growth trial was there a significant effect of method of providing the ground barley on performance. With whole barley, feed efficiency was significantly inferior to that obtained with ground barley, being 20–37% lower when whole grain and concentrates were mixed, but only 5–16% lower when the whole grain and concentrates were provided separately. The digestibility trial indicated no differences between the two forms of whole grain, but a superior utilization of the ground grain. Dry matter digestibility of both forms of whole grain was significantly greater in the younger pigs than in the older pigs, increasing from 63.0 to 71.1% for the whole grain, and from 62.3 to 73.2% for the rehydrated acid-preserved whole grain. Dry matter digestibility of ground grain averaged 77.6% and was not affected by age of pig, but was significantly reduced by ad libitum feeding.