Comparative Effects of Urea, Uramite, Biuret Soybean Protein, and Creatine on Digestion and Nitrogen Metabolism in Lambs

Abstract

Digestion and nitrogen metabolism trials were conducted to compare Uramite, a urea-formaldhyde condensation compound; crude biuret; biuret; purified soybean protein; and creatine with urea as sources of nitrogen for lambs. The various compounds studied were included alone or with urea in semi-purified, iso-caloric, and iso-nitrogenous rations to provide 67% of the ration nitrogen. Nitrogen from Uramite was used inefficiently. A significant decrease in the apparent digestibility of crude protein was obtained when it contributed 4, 8, 16, and 32% of the supplementary non-protein nitrogen. A highly significant decrease in crude fiber digestibility resulted with the 2 and 4% levels of Uramite, a significant decrease with the 8 and 16% levels but no decrease with the 32% level. Nitrogen utilization and nutrient digestion were not significantly changed when 50% of the supplemental nitrogen was supplied by crude biuret. Apparent digestibility of protein was significantly depressed when all supplemental nitrogen was supplied by crude biuret. When pure biuret supplied 100% of the supplemental nitrogen instead of urea, nutrient digestion and nitrogen utilization were significantly depressed. Nutrient digestibility was greater when purified soybean protein or a nitrogen equivalent mixture of urea and creatine replaced urea as the source of supplemental nitrogen. This improvement, however, was significant only in the case of organic matter and crude fiber digestibility. Nitrogen utilization was significantly improved by soybean protein and creatine. None of the materials at the levels studied elicited any signs of toxicity.