The effects of feeding method, milk allowance and social factors on milk feeding behaviour and cross-sucking in group housed dairy calves

Cross-sucking is non-nutritive sucking of another calf's body. This detrimental behaviour is seen in artificially reared calves, but never in calves reared by the dam. The behaviour stems from a redirection of the natural sucking behaviour. Studies of calves fed milk in buckets have shown that cross-sucking may be reduced if teat buckets are used instead of open buckets. Prolonging the milk meal by reducing the milk flow rate and leaving the teat buckets available after the meal ensure the largest reduction of cross-sucking. These results are predominantly based on investigations with calves housed individually, in pairs or in groups of three. Prolonging the milk meal by reducing the milk flow rate in calves fed by computer-controlled milk feeders also reduced the occurrence of cross-sucking. Under commercial conditions there are often 20-40 calves per feeding station and much aggression around and displacement from the feeding station is seen. Furthermore, there is much cross-sucking around the feeding station. A gate may be fitted to the feeding station that protects the calf from displacement and prevents cross-sucking on the calf in the station. It is noted that both reduced milk flow rate and gating the feeding station may reduce the capacity of the feeder. Under standard conditions the calves pay several unrewarded visits to the computer-controlled milk feeder and restricted milk feeding has been found to increase the number of unrewarded visits. Cross-sucking may also be motivated by hunger and the influence of milk allowance, as well as distribution of milk meals, on use of the feeder and cross-sucking should be investigated. Furthermore, future research should focus on what an appropriate number of calves per feeding station is for computer-controlled milk feeders to function optimally and to ensure minimal problems due to aggression and cross-sucking. (C) 2002 Elsevier Science B.V. All rights reserved.