The aim of the study was to evaluate the effect of replacing cereal grains and soyabean oilmeal with rapeseed cake or glycerine in the rations of high-yielding cows. The experiment was carried out on 56 Polish HF cows allotted to 4 groups of 14 animals according to body weight, milk yield, and parity. The cows were fed rations differing in protein and energy content from 6 weeks before calving to 12 weeks of lactation. The basal diet of all groups was composed of silages, meadow hay and concentrate feeds. In the experimental groups, the cereal grains and soyabean oilmeal fed to the control group (C) were replaced by rapeseed cake (30%; groups RC and RC_W6 ) or glycerine (5%, group G). For the entire experimental period, no statistical differences were found among the groups in the daily intake of dry matter and other nutrients, except PDIE. The control group cows produced about 1.2 kg/day less milk (P>0.05), but the contents of dry matter, fat, protein, lactose, and urea in milk were similar. The highest concentration of free fatty acids and β-hydroxybutyric acid were found in the milk of the control cows. Introducing 5% glycerol into the diet did not cause any significant changes in production parameters. The serum metabolite profile of cows fed the experimental diets suggests that these cows could have been at a lower risk of ketosis.