Duration of weaning, starter intake, and weight gain of dairy calves fed large amounts of milk.

When calves are weaned abruptly off large amounts of milk, weight gain is reduced as a result of low intake of starter. We compared gradual and abrupt weaning of 40 calves allowed to drink up to 12kg of milk/d by automated feeders, housed in groups of 4, and weaned at 41 d abruptly or over 3 gradual weaning periods (4, 10, or 22 d), with one calf within each group randomly allocated to each treatment, balancing for sex and birth weight. During the milk-feeding period, the calves weaned over 22 d drank the least milk and ate the most starter, but these calves had the lowest total digestible energy intake and weight gains. The abruptly weaned calves had the highest digestible energy intakes and weight gains during the period before weaning. During the 9 d following weaning, the calves weaned over 22 and 10 d ate more starter and had better weight gains than abruptly weaned calves and those weaned over 4 d. Abruptly weaned calves lost weight during this period. In summary, gradual weaning improved starter intake, but because of reduced milk availability, this resulted in reduced total digestible energy intake before weaning. Weaning over 10 d resulted in the best overall weight gains over the study.