Weaning distress in dairy calves: Acute behavioural responses by limit-fed calves

Weaning typically involves both dietary and social changes as the transition from milk to solid feed is normally accompanied by reduced contact with the dam. Dairy calves provide a model to study the effect of weaning from milk independent of separation, as calves are typically separated from the cow and then fed milk artificially for several weeks before weaning. Calves likely vary in their reliance on milk, as some animals will be better established than others on solid feed before weaning. The aim of this study was to describe the immediate behavioural responses of dairy calves (n = 30) to weaning from milk, and to compare acute responses when calves varied in consumption of solid food before weaning. To encourage the intake of solid feed some calves were fed milk diluted with water while other calves were fed non-diluted milk. Calves on diluted milk ate twice as much solid feed (calf starter) before weaning, approximately 2 kg/ day. However, this treatment did not increase starter intake after weaning and did not affect the immediate behavioural response to weaning, suggesting that the acute weaning response is due to factors other than the lack of milk. To explore these other factors calves were weaned by either complete cessation of the milk-feeding routine ('abrupt weaning'), or with continued access to the milk-feeding system but with warm water instead of milk. Calves weaned abruptly showed a stronger immediate behavioural response to weaning than did those calves provided with continued access to the milk-feeding system. The abruptly weaned calves vocalized at more than 3 times the rate, averaging more than 120 calls during the 20 min after feeding. These calves were also more active than calves with continued access to the feeding apparatus, as shown by a higher rate of movements in the pen and more time with the head outside of the pen. The reduced acute response to weaning by calves with continued access to the milk feeding system may be due to the behaviours that this system facilitates (e.g. sucking on the milk bucket), to the ingestion of the warm water, or to other rewarding attributes of the feeding system. (c) 2007 Elsevier B.V. All rights reserved.