Abstract
The aim of the study was to compare the effect of feeding a hybrid rye grain in rations for dairy cows during the first 100 days of lactation on body condition, milk yield and milk composition. Feeding cows with concentrates containing in its composition 25% or 40% of the ground hybrid rye did not decrease the intake of concentrate or PMR rations as compared to the control group. The introduction of 25% or 40% of the rye hybrid variety Visello to the concentrates did not reduce the milk yield of the cows during the first 100 days of lactation. No significant differences in the chemical composition of the milk were observed. The cows fed rye maintained their weight and body condition during the first 100 days of lactation at the same level. The addition of hybrid rye grains in the amount of 25% to concentrate had no significant effect on the fatty acid profile of the milk whereas 40% of rye improved fatty acids composition by decreasing C18:0 and increasing C18:1 n-9 in the milk.