**9. Conclusion**

Increase of biofuel ethanol production has resulted in an increase of the production of wheat-based distiller grain, and thus increases in the use of distiller grains in the diets of livestock animals. The chemical composition of wheat distiller grain can vary considerably from plant to plant or between batches within plant depending on the type of wheat fermented and technology of fermentation used in ethanol plants. Direct nutrient analysis of each lot of wheat distiller grain is recommended if such information is not provided to ensure accurate ration formulation for precisely feeding ruminant animals. Wheat distiller grain contains higher protein, fibre, fat and minerals but very lower starch than the original grain. Protein quality in wheat distiller grain is high with moderate rumen degradability, and its fibre is highly digestible in the rumen. Therefore, wheat distiller grain can be used as good protein and energy source in ruminant diets. Wheat distiller grain is commonly fed in beef and dairy cattle feeding as either a protein or energy source or both. It is recommended that wheat distiller grain not be included in dairy rations at levels above 20%, whereas they can be fed to 40% of the diet of growing and finishing cattle. Wheat distiller grain can also be used as fibre source to partly replace roughage in cattle diets, whereas its effectiveness of stimulating chewing activity and maintaining rumen pH status is limited. Thus, feeding wheat distiller grain in place of roughage may increase the risk of rumen acidosis especially if it is used to replace all of the forage in beef cattle diets. With the mandatory inclusion of renewable fuels in gasoline, distiller grain is certain to continue to be an important feed source for ruminants. Development of rapid analysis procedures such as near-infrared spectroscopy may allow this ingredient to be formulated into diets with greater accuracy. The wheat distiller grain is high in nitrogen and phosphorus, and high inclusion in cattle diets, especially when it is used as energy source in cattle diets may exceed the protein requirement, thus increase the manure nitrogen excretion, a factor that needs to be considered for manure management.
