The effect of cereal and protein source on the energy intake and nitrogen balance of fattening lambs given all-concentrate diets

Abstract

Energy intake and nitrogen balance studies have been conducted on 12 lambs fed ad libitum on four all-concentrate diets of equal crude-protein content in an experiment of latin square design. Each diet contained one cereal, either barley or oats and one protein supplement, either white-fish meal or soya bean meal.Protein supplements had no influence on energy intake, but intake was significantly higher when the lambs were given barley rather than oat diets.There were highly significant differences in the degree of utilization of digested nitrogen between diets containing fish meal and soya bean meal, and between diets containing barley and oats.The energy: nitrogen ratio of urine was inversely related to the proportion of urinary nitrogen present as urea and directly related to the degree of utilization of digested nitrogen.