Prepn (not claimed) and use as poultry feed additive: E. S. Blake, R. J. Wineman, US 2745745 (1956 to Monsanto). HPLC determn in feeds: A. Baudichau et al., J. Sci. Food Agric. 38, 1 (1987). Use as a feed additive for livestock: A. Papas et al., J. Nutr. 104, 653 (1974); A. K. Clark, A. H. Rakes, J. Dairy Sci. 65, 1493 (1982); D. H. Reifsnyder et al., J. Nutr. 114, 1705 (1984). Efficacy of calcium salt vs free acid: K. P. Boebel, D. H. Baker, Poult. Sci. 61, 1167 (1982).