Effect of Humic/Fulvic Acid in Beef Cattle Finishing Diets on Animal Performance, Ruminal Ammonia and Serum Urea Nitrogen Concentration

Abstract McMurphy, C.P., Duff, G.C., Harris, M.A., Sanders, S.R., Chirase, N.K., Bailey, C.R. and Ibrahim, R.M. 2009. Effect of humic/fulvic acid in beef cattle finishing diets on animal performance, ruminal ammonia and serum urea nitrogen concentration. J. Appl. Anim. Res., 35: 97–100. This study was designed to investigate the effects of a humate supplement on rumen ammonia N (RAN), serum urea N (SUN) and live performance in beef cattle finishing diets. Twenty-four English cross steers (BW 432±5 kg) were stratified by weight, randomly assigned to individual pens and fed one of the four diets, containing 0 (control), 0.5, 1.0 or 1.5% humic/fulvic acid, for 56 d. Control diets contained 33.3 mg/kg monensin. Steers were weighed at d 0, 28 and 56. Blood (jugular veni-puncture) samples and rumen (esophageal tube) samples were taken prior to feeding on d 0 and there after prior to and 4 h post feeding on d 28 and 56. Rumen fluid pH was determined immediately, acidified with HCl and stored (-20C) for subsequen...