1. duPont, E.I., de Nemours and Co., “Urea and Ruminant Nutrition,” Wilmington, Delaware, 1958.
2. Reid, J.T., J. Dairy Sci. 36:955 (1953).
3. Loosli, J.K., in “Plant Protein Foodstuffs,” Edited by A.M. Altschul, Academic Press, New York, 1958.
4. Chalupa, W., J. Anim. Sci. 27:207 (1968).
5. Bell, M.C., W.D. Gallup and C.K. Whitehair, Ibid. 12:787 (1953).