Feeding on concentrates in the milking parlour was analysed in order to establish if too short time for the consumption of concentrate caused increased heart rate (HR), one of the stress indicators. 27 highly productive dairy cows were given from 1 to 5 kg of concentrate in the milking parlour. The average quantity of consumed concentrate at a single milking amounted to 2.14 kg, and the average speed of consumption was 249.7 g min-1. Average HR was 82,38 min-1. At the evening milking cows had higher HR (83.4 min-1), compared to the morning one (81.2 min-1). In the second month after calving HR of cows was higher (85.10 min-1) compared to the first (81.04 min-1) and the third month (80.79 min-1) after calving. It has been established that the increase of HR did not occur up to the 3 kg of consumed concentrate per milking. However, higher quantity of consumed concentrate (over 3 kg) resulted in increased HR. If the cows received larger quantities of concentrate, HR increased towards the end of milking process. It can be concluded that large quantities of concentrate, which could not be eaten in a short period of available time at milking, caused stress in highly productive dairy cows.