Effect of Varying Roughage to Concentrate Ratios on the Utilization by Lambs of Rations Differing in Physical Form

A series of growth and digestibility studies were conducted with lambs to determine the effect of pelleting rations differing in level of roughage. Feeding a high roughage ration (about 60%) in the ground and mixed form did not increase performance as compared to conventional ration composed of shelled corn and alfalfa hay. However, the pelleting of this ration increased feed consumption, increased gains and decreased feed required per unit gain. Feeding a low roughage ration (about 40% roughage) either in the ground-mixed or pelleted form increased gains to similar degree. However, the lambs fed the low roughage pelleted ration were more efficient. Based on digestible calories the lambs fed the low roughage pelleted ration were more efficient in converting energy into gain as compared to the lambs fed the high roughage pelleted ration. Pelleting either the high roughage or low roughage ration did not effect organic matter or protein digestibility as compared to the ground mixed ration. Cellulose digestibility was decreased for both rations. Nitrogen retention was higher for the lambs fed the pelleted rations than for the lambs fed the ground-mixed rations.