The effectiveness of ammonia and sulfur dioxide as preservatives for high-moisture barley grain and their influence on digestibility, rate and efficiency of gain, and the selenium and thiamin status of feedlot steers were examined. Duplicate 18-t plastic-bag bins were prepared with the following type and amount (wt/wt, dry matter (DM) basis) of preservative applied to low (23%) or high (32%) moisture barley: (1) high-moisture barley, no preservative (control); (2) high-moisture barley, 1.1% ammonia (1.1%-NH3); (3) high-moisture barley, 2.3% ammonia (2.3%-NH3); (4) low-moisture barley, 1.3% sulfur dioxide (1.3%-LMSO2); and (5) high-moisture barley, 1.7% sulfur dioxide (1.7%-SO2). Heating occurred in the control barley. Mold and yeast populations were substantially reduced in barley treated with ammonia which appeared well preserved. Considerable deterioration occurred in the core of one 1.3%-LMSO2 bin. Crude protein digestibility was lower (P < 0.001) for an all-concentrate diet containing 1.1%-NH3 barley fed whole (66.8%) than for three other diets containing rolled barley (mean 81.1%), although apparent digestibilities of other feed components were similar (P > 0.05). When the preserved grains were each fed to a group of 12 steers (363 kg initial weight) along with 1.0 kg hay daily, gains were 1.46, 1.72, 1.67, 1.33 and 1.31 kg d−1 (P < 0.05) for steers fed control, 1.1%-NH3, 2.3%-NH3, 1.3%-LMSO2, or 1.7%-SO2-treated barley, respectively. Corresponding kilograms of DM required per kilogram of grain were 6.11, 5.41, 5.53, 6.76, and 6.72 (P < 0.05). Serum selenium concentrations and thiamin status were similar (P > 0.05) for steers in all treatments at the end of the test. Key words: High-moisture barley, steers, preservatives, ammonia, sulfur dioxide
