Effects of Protein Supply from Soyhulls and Wheat Bran on Ruminal Metabolism, Nutrient Digestion and Ruminal and Omasal Concentrations of Soluble Non-Ammonia Nitrogen of Steers (Report‪)‬

INTRODUCTION Dietary protein available for absorption in the intestine is often supplemented to improve the performance of cattle. The common practice for increasing metabolizable protein supply is to feed protein supplements that are low in ruminal degradability (NRC, 2001). However, typical rumen-undegraded protein (RUP) supplements such as corn gluten meal (CGM) and palm meal are usually the most expensive ingredients in cattle diets. Brans have varying ruminal crude protein (CP) degradabilities despite lower CP levels compared to that of typical protein sources; rumen-degraded protein (RDP) contents of rice hull, soyhulls (SH) and wheat bran (WB) are estimated to be 52.3, 55.4 and 79.3%, respectively (NRC, 2001). We thought it might be interesting to find out if rice hull or SH having relatively low ruminal degradability could play a role of RUP in diets. If so, manipulation of ruminal protein release using brans could be beneficial due to their lower prices than conventional protein supplements. However, lack of data on metabolic or digestive responses to increasing dietary CP contents and RUP contents with brans makes it difficult to use them as protein sources.