Changes in suckling behaviour of dairy calves nursed by their dam during the first month post partum

We observed housed dairy calves nursed by their dam to examine the development of sucking, teat change, butting, manipulating and other behaviours during the first four weeks post partum. The study herd was kept in a deep litter system with access to an out-door area. The nursing cows were milked two to three times daily and calves could suckle them at will. Twelve cow–calf pairs were followed to obtain video recordings of two nursings per pair at 7, 14 and 28 days post partum. Videos were analysed for the duration and frequency of all observable behaviours within a nursing.The nursings lasted on average 7.2 min ranging from 2.8 to 16.3 min. Sucking made up 66% of the total nursing time and occurred throughout the nursing. Total sucking and butting were higher at the beginning of the nursing and decreased towards the end. Older calves had longer nursing durations (p < 0.01), spent more time sucking (p < 0.05) and less time pausing (close p < 0.05). Older calves performed less butting (p < 0.01) and tended to release the teat more often (p < 0.1). In 86.6% of the nursings calves only sucked on one or two teats. The percentage of the nursing time spent sucking on a preferred teat tended to be lower in older calves (p < 0.1). The sucking rate averaged 2.1 mouth movements per second, and each calf had its own steady rate. No cross-sucking events were observed between calves. The behaviour of the calves suggests that the cows’ milk production was higher than the calves’ needs.