Norwegian Red dairy cows (n = 48) in early/mid lactation were divided in three groups and fed a ration consisting of grass silage and concentrate, where the concentrates were barley based but with different additional protein sources. These were: completely barley-based with no additional protein source (BAR), additional protein from soybean meal (SMB) or additional protein from yeast (Cyberlindnera jadinii) (YEA). The SBM and YEA concentrates had a higher protein content than the barley concentrate. Four batches of cheese were made from pooled milk from each of the three groups of dairy cows and individual milk samples were collected five times during the experiment and were analysed.