Nutrition - 1991 Kegley, E. B., Harvey, R. W., & Spears, J. W. (1991). Effects of lysocellin and calcium level on mineral metabolism, performance and ruminal and plasma characteristics of beef steers. Journal of Animal Science, 69(2), 782. Chen, H., & Schwartz, S. J. (1991). Fractionation of butter oil with supercritical carbon dioxide. Journal of Dairy Science, 74, 130.