Although many calorimeter studies have examined CH4 emissions from confined cows offered conserved forage-based diets, fewer studies have examined emissions from grazing dairy cows. Methane emissions from grazing cattle are normally measured using the SF6 technique, with a recent study by Muñoz et al. (2012) demonstrating that the technique can provide estimates of CH4 emissions that are comparable with direct measurements undertaken within respiration calorimeters