In Holland a study of Wageningen University & Research shows that the composition of the ration of dairy cows has influence on the emission of methane. The study shows that farms that feed more grass silage and less maize have a higher methane emission. Pasturing instead of feeding grass silage, in particular in spring had a positive influence on the limiting of the emission of methane. During practical research methane emission during full pasturing was 280 gram per cow per day; with summer feeding (grass in barn) 380 gram per cow per day and with keeping them inside and feeding grass silage 440 gram per cow per day.