Effects of tempering and degree of processing of barley grain on the performance of bulls in the feedlot

A 2 × 3 factorially designed experiment with 216 bull calves (288 ± 43 kg) was conducted in which tempered and dry barley grains were lightly rolled (most of kernels cracked, few broken), medium rolled, or crushed (almost all kernels broken) and included in a feedlot diet containing 90% concentrate and 10% barley silage on a dry matter (DM) basis. In the tempering process 6% water was added to the control barley, which initially contained 13% moisture, and the damp grain was allowed to stand overnight at room temperature before rolling. Tempering had no influence on rate or efficiency of gain of the bulls during the 134-d trial or on carcass characteristics. Cattle fed slightly rolled, medium rolled, and crushed barley (kernel thicknesses of 2.70, 2.56 and 2.31 mm) gained 1.55, 1.57 and 1.61 kg d −1 , respectively, with no difference detected between treatments. Corresponding DM intakes were 8.04, 7.79 and 7.54 kg d −1 (P < 0.05). Dry matter intake to gain ratios were 5.20, 4.96 and 4.68 (P < 0.05). Carcasses of bulls fed crushed barley had more (P < 0.05) grade fat than bulls fed slightly rolled barley. It was concluded that there was no advantage in tempering barley which initially contained 13% moisture. Efficiency of gain was improved as the degree of processing of barley was increased.