Repeatability and ranking of long-term enteric methane emissions measurement on dairy cows across diets and time using GreenFeed system in farm-conditions

•The high repeatability for CH4 emission is related to differences among individuals.•Differences in CH4 emission among diets were persistent over 6 months of lactation.•GreenFeed is reliable in differentiating CH4 emission in dairy herds across diets.•The ranking of individuals based on their CH4 emission is not persistent across time within a same diet.