Predicting enteric methane emission of grass silage for dairy cows: Regression analysis in search of a predictive relationship between feed characteristics of grass silage and enteric methane emission (g per kg dry matter)

Empirical models to predict enteric methane emissions from dairy cows, based on the chemical feed characteristics of grass herbage and silage, have been constructed from a dataset containing information from 2012 to 2022. For grass herbage, no qualitatively sound model could be built with the current data. For grass silage, two new linear models have been developed that predict CH4 emissions as a function of the levels of crude fat, digestibility coefficient of organic matter, acetic acid, and crude fibre ór ADF. Both models provide a good prediction of the CH4 emission factor but are highly empirical, lacking physiological underpinning, and support for the models presented here needs to be increased via validation against independent data.