The study examined the behavioural and productivity effects of separating 24 Holstein dairy cows from their calves early (1 day old) or late (14 days old). The behaviour of the cow and calf was observed for an hour prior to separation and for the initial 24h after separation. The social behaviour (licking other calf, rubbing or butting its head the unfamiliar calf and wagging its tail) of the calves at 6 weeks of age was tested by introducing a early or late weaned calf to an unfamiliar calf. The cow and her calf were mostly inactive when they were observed prior to separation. After separation, both the cow and calf from the late separation group placed their heads outside the pens more often the cows and calves from the early separation group. Cows from the late separation group also called and moved around the pen more than cows separated from their calves early. In the two week period immediately following calving, the late separation cows yielded significantly less milk than the early separation cow. Part of the lower milk yield can be attributed to the milk consumption of the calf. The time of separation from the calf did not result in differences in milk yields from 15 to 150 days after calving. The rate of weight gain for calves separated from the cow at 14 days of age was three times the rate seen in calves separated at 1 day of age. At six weeks of age, the calves that were separated from the dam later, exhibited more social behaviours towards the unfamiliar calf than those separated early. The results show that the intensity of the response to separation by both the cow and calf increased with the amount of time they spent together after birth. However, the delay in separation allowed the calves to gain more weight and may have an impact on the social development of the calves.