Quality and precision processing of barley grain affected intake and digestibility of dry matter in feedlot steers

Abstract

Yang, W. Z., Oba, M. and McAllister, T. A. 2013. Quality and precision processing of barley grain affected intake and digestibility of dry matter in feedlot steers. Can. J. Anim. Sci. 93: 251–260. A study was conducted to determine the impact of barley quality and precision processing to account for the impact of variable kernel uniformity on ruminal pH and fermentation, and digestibility in the digestive tract of steers. Eight ruminally cannulated steers were used in a replicated 4×4 Latin square experiment. The four diets consisted of light-weight barley (LB) precision-processed with roller setting based on kernel size; heavy-weight barley (HB) precision-processed; LB and HB grain mixed equal parts then processed at a single roller setting (CON); or LB and HB precision-processed and mixed equal parts (PP). The diets consisted of 10% barley silage and 90% concentrate [dry matter (DM) basis]. Dry matter intake by steers fed LB was greater (P=0.04) than by steers fed HB. Intakes of DM and other nutrients were greater (P=0.04) for steers fed PP than for steers fed CON. There were no differences (P>0.14) in ruminal pH and fermentation among treatments. Digestibility of DM in the total digestive tract tended (P=0.06) to be less with LB than with HB. Precision processing increased digestibility of crude proteion (P=0.04) and acid detergent fibre (P=0.06) resulting in a trend (P=0.10) towards increasing organic matter digestibility as compared with CON. The results suggest that screening of blended barley into more uniform fractions and precision processing of each fraction could increase intake of digestible nutrients for feedlot cattle.