Calves with free milk intake from birth on develop much better than calves on a restricted milk diet. Weaning calves off large amounts of milk is a challenge because delayed forestomach development following ad libitum milk feeding means that weaning too quickly can lead to drops in body weight and metabolic disorders. A total of 80 calves were studied across 4 experimental groups: (1) Weaning within 3 or (2) within 6 weeks; (3) Weaning according to concentrate intake, and (4) weaning according to average daily gain. Calves weaned within 3 weeks had higher free fatty acid and urea concentrations in blood plasma during weaning, suggesting the mobilization of body reserves in these calves.