Most roughage used for wintering beef cattle in eastern Oregon and in much of the west is a low quality native meadow hay. Generally, this hay is low yielding and is harvested near maturity to obtain maximum yield. While low in crude protein–7 to 9%–it has a gross energy content approximating that of better quality roughages. Hay harvested past maturity often has a crude-protein content as low as 4 or 5%. Cellulose digestibility is high–60 to 70%–but protein digestibility is low–45 to 50% (Wallace and Raleigh, 1960; Wallace et al., 1961a, b). Considerable research shows that increasing protein content of a low protein diet will increase feed intake and gains (Bush et al.,1955; Ross et al., 1954; Woods et al., 1956). Urea as a protein extender for ruminant feeding has been studied extensively and the literature reviewed by Belasco (1954, 1955) and Anderson et al. (1959). The purpose of the work reported in this paper was to determine: (1) the level of protein supplementation to a meadow hay ration that would give optimum performance, and (2) to what degree urea could be used to replace the protein supplement.

1963 Raleigh Effect of urea at different nitrogen levels on digestibility and on