For example, it is well known that increasing the concentrate proportion of the diet (especially increasing starch concentration) generally decreases CH4 emissions. Using a modeling approach, Benchaar et al. (2001) showed that CH4 yield was reduced when beet pulp (fibrous concentrate) was replaced by barley (starchy concentrate), although a recent study (Hassanat et al., 2013) suggests that a critical dietary concentration of starch is required to alter ruminal methanogenesis. Usually, corn meal is used in dairy cow rations as the starchy ingredient; however, high usage of corn meal is not desirable for 2 primary reasons: a higher risk of rumen acidosis and the economic cost.