Direct observations were performed to determine the calves’ behaviour on day 1, 2 and 3 of week 0. The animals were observed for a total duration of 5 h per day consisting of hourly observation periods (08:00–09:00 h, 10:00–11:00 h, 12:00–13:00 h, 14:00–15:00 h and 16:00–17:00 h). The instantaneous scan sampling technique with 5 min intervals was used to count the total number of vocalisations of each group. Two consecutive 5 min periods were summarized and the number of vocalisations per calf in a 10 min period was calculated.