Protein and energy value of cereal grains in ruminants as a result of ruminal degradation of crude protein and starch

For the quantitative description of the protein and energy value of cereal grains in ruminants, extent and kinetics of ruminal degradation of crude protein (XP) and starch are essential characteristics. Several studies have shown that ruminal degradation of XP and starch differ between grain varieties. So far there are no experimental studies available to assess this variation in more detail, or even to predict them with appropriate methods. Using the in sacco method, the kinetic of degradation of dry matter (DM), XP and starch is determined under standardized conditions. Thereby firstly a comprehensive data base is created on the ruminal degradation of DM, XP and starch from maize, wheat, barley, rye and triticale. These analyses are complemented with studies on gas formation and its kinetics using the Hohenheim Gas Test for the determination of the digestibility and content of metabolizable energy. With this method also the contents of utilizable crude protein (nXP) are estimated by means of the ammonia release. Finally, in vitro specific NIRS calibrations for the key figures of XP and starch degradation as well as for gas formation and nXP shall be developed for grain sample screening.