Behaviours related to milk intake in dairy calves

Dairy calves are usually raised by artificial milk feeding systems where their need to perform sucking is not fulfilled. This thesis investigated the effects of various milk feeding and weaning methods on the calves’ behaviour, intake and weight gain. In paper I calves were fed from an automatic milk feeder. It was found that gradual weaning over 14 days reduced the occurrence of cross-sucking immediately after weaning and it stimulated the calves to eat more concentrate during weaning compared to abrupt weaning. A high milk allowance (9.2 vs. 4.8 litres) reduced the number and duration of unrewarded visits and thus reduced individual calves’ occupancy of the feeder. In paper II calves were fed milk from teat-bars with either a common milk compartment for all teats or a separate milk compartments for every teat. The teat-bar design did not affect the variation in milk intake within the groups, but a teat-bar with separate compartments increased the teat switching while there was still milk left in one or more of the compartments. Gradual weaning over 10 days stimulated the calves to eat more concentrate during weaning as compared to weaning by diluting the milk. The occurrence of cross-sucking was low with this milk feeding system. In paper III calves were fed from automatic milk feeders and it was found that a large portion size (2.0 vs. 1.0 litres) increased the mean duration of rewarded visits. In combination with a slow flow (300 vs. 600 ml/min) it increased the number and daily duration of visits where the calves did not drink milk even though they could. The treatments did not influence the percentage of calves performing cross-sucking, but a large portion size or a slow milk flow reduced the percentage of calves performing cross-sucking 60 min or more after a visit. In paper IV calves were fed milk ad libitum from either one teat or five teats per group. Five teats per group increased the time manipulating the teats but lowered the time waiting for access to a teat, access to concentrate and the time eating concentrate. Five teats per group also increased the occurrence of cross-sucking directed towards the head of another calf. The conclusion of this thesis is that calves should be fed milk in large portions to provide an out-let for their sucking motivation and they should be weaned gradually over 10-14 days to stimulate the concentrate intake and reduce cross-sucking after weaning