Potential of milk fatty acid composition to predict diet composition and authenticate feeding systems and altitude origin of European bulk milk

Abstract The aims of this work were to elucidate the potential of using milk fatty acid (FA) concentration to predict cow diet composition and altitude of bulk milk collected in 10 different European countries and to authenticate cow-feeding systems and altitude of the production area using a data set of 1,248 bulk cow milk samples and associated farm records. The predictions based on FA for cow diet composition were excellent for the proportions of fresh herbage [coefficient of determination (R 2 )=0.81], good for hay, total herbage-derived forages, and total preserved forages (R 2 >0.73), intermediate for corn silage and grass silage (R 2 >0.62), and poor for concentrates (R 2 93% of samples correctly classified), but the presence of mixed diets reduced the discrimination. Altitude prediction reliability was intermediate (R 2