Urea and Biuret for Lambs

C ORN silage is a major source of roughage for ruminants in the cornbelt, because it is one of the most productive crops of total digestible nutrients and animal gains per acre. However, to make up a complete growingfinishing ration with corn silage it is necessary to supplement it with sources of energy, nitrogen and minerals. The addition of urea to corn, sorghum or grass at ensiling has given variable results (Cullison, 1944; Woodward and Shepherd, 1944; Wise et al., 1944; Davis, 1944; Archibald, 1946; K/osterman et al. 1961). Considerable research has been directed toward the study of biuret as a nonprotein nitrogen (NPN) source for ruminants (Repp et al., 1955; Ewan et al., 1958; Hatfield et al., 1959; Campbell et al., 1963; Karr et al., 1964; Johnson and McCIure, I964), but data have not been reported concerning its value as a preservative or a nitrogen source in corn silage. The present series of experiments was conducted to: (1) nutritionally evaluate complete ensiled diets, (2) compare urea and biuret as NPN sources in a complete ensiled diet, (3) determine the fate of urea and of biuret during the ensiling and fermentation process, (4) determine the effect of adding various concentrate mixtures on organic acid production during fermentation, and (5) study the effect of diethylstilbestrol implants (DES) on utilization of nitrogen.