First results of a screening method for GHG emission measurements in European dairy cattle barns

The effects of cattle farming systems and individual management practices on GHG emissions have been studied by applying a screening method on eight European countries totalizing 60 dairy farms and four seasonal measurements. This method is based on indoor and outdoor CO2, CH4, and N2O concentration measurements and on a questionnaire developed to estimate the carbon mass balance at the building scale. The results of the questionnaire were also used to characterize the farm diversity. This international survey conducted with the same measurement method helped identifying the main factors influencing GHG emissions as well as the existing low-emitting systems: the calculated emissions based on concentration measurements showed that CH4 emissions from manure could double those from the enteric fermentation of the animals highlighting the importance of manure management as a GHG mitigation approach; the detection level of the N2O emissions was below 1 g N-N2O/animal/day; in some farms, the emission results showed very few seasonal variations over the year while, for other ones, seasonal variations were well observed; the results showed well detectable GHG emission reductions related to changes in farm practices.