Summarized cereal grain characteristics affecting digestive behavior and nutrient utilization on a quantitative basis: Comparison among oat, hull barley, and hulless barley grain

This article aims to review and summarize recently obtained information on cereal grains (oat and barley) for livestock regarding grain characteristics affecting digestive behavior and nutrient utilization. The analyses included the determination and evaluation of the physiochemical and nutrient profiles, total digestible nutrients and energy values, protein and carbohydrate subfractions, rumen degradation kinetics, intestinal digestion of nutrients, feed milk value, degraded protein balance, and truly absorbable nutrient supply using the protein evaluation DVE/OEB model to achieve target values for potential high net absorbable protein in the small intestine while holding any N loss in the rumen to a low level. Future research directions and implications are also provided. The information in this article gives better insight into summarized nutrient characteristics of cereal grains, the large difference between oat and barley grain, hulless and hulled barley, and provides information about nutrition evaluation systems that more accurately account for digestive processes in ruminants on a quantitative basis. Future studies are needed to reveal the intrinsic structure features of cereal grains at a molecular level and determine how technological processing induces the change in molecular structure in relation to nutrient metabolism, biofunction, utilization, and availability in livestock.