The Dutch ministry of Agriculture, Nature and Food Quality has set strict reduction targets to reduce methane (CH4) and ammonia emissions simultaneously. This one-year report is part of a multiannual research to discover the mechanisms with which the fresh grass quality influences the enteric CH4 emission. This knowledge contributes to finding ways for simultaneous reduction. Results of a one-year grazing experiment show that the CH4 emission based on fresh grass is possibly overestimated. Results of multiple years with different weather circumstances and additional insights in rumen degradation characteristics are needed to further substantiate.