EFFECTS OF BARLEY VOLUME-WEIGHT AND PROCESSING METHOD ON FEEDLOT PERFORMANCE OF FINISHING STEERS

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Abstract
Barley of three different volume-weights (VW) (light, 47.8; medium, 55.6; heavy, 66.6 kg hL−1) was subjected to two processing treatments (DR, dry rolled; SF, steam flaked) and fed to 192 yearling steers (avg. body weight 332 kg) at a level of 85% of the dietary dry matter (DM) in combination with barley silage (10.75% of DM) and mineral-vitamin premix (4.25% of DM) during the finishing period. No significant two- and three-way interactions were observed for any of the traits studied. Average daily gain (ADG) of cattle fed SF and DR diets was similar (P > 0.05) except during the first 27 d of the trial in which the SF steers gained 9.4% faster (P < 0.05) than the DR steers. Dry matter intake (DMI) of steers fed SF barley tended to be higher (P < 0.10) in period one and in period three than for those fed DR barley but was similar for both processing groups in periods two and four and overall. Dry matter consumed per unit of liveweight gain (DM/G) was similar for the two processing treatments during all periods and overall although it tended (P < 0.10) to be lower for the DR steers during period two. Volume-weight had no effect (P > 0.05) on ADG or DMI. Overall, DM/G decreased (P < 0.01) an average 1.2% for each unit (kg hL−1 increase in VW from 47.8 to 55.6 kg hL−1. DM/G was similar for cattle fed medium and heavy barley. Large steers (avg. bodyweight 350 kg) gained 17.5% faster (P < 0.01), consumed 12% more (P < 0.01) dry matter and required 4.9% less (P < 0.01) DM per unit of gain than small steers (avg. bodyweight 314 kg). Steam flaking of the barley produced carcasses with 0.14 cm more (P < 0.05) grade fat and resulted in 31% fewer (P < 0.05) liver condemnations due to abscesses than dry rolling but did not influence the other carcass quality perameters. Medium VW barley resulted in lower (P < 0.05) grade fat than either light or heavy barley, which produced similar grade fat measurements. Large steers, marketed at an average liveweight that was 14.5 kg heavier (P < 0.01) than the small steers, had lower (P < 0.05) marbling scores than the small steers. Key words: Barley, volume-weight, steers, processing, dry rolling, steam flaking