Influence of weaning method on growth, intake, and selected blood metabolites in Jersey calves.

Forty-three Jersey calves were assigned randomly at birth to treatments that evaluated the method of weaning on growth, intake, and concentrations of blood metabolites that were indicative of ruminal development. The three experimental treatments were 1) milk replacer fed at 10% of BW until abrupt weaning at 35 d of age, 2) milk replacer fed at 10% of BW until 28 d and then at 5% of BW until weaning at 35 d of age, or 3) milk replacer fed at 10% of BW until intake of calf starter reached 454 g/d for 2 consecutive d, at which time calves were weaned. Commercial milk replacer was reconstituted to 12.5% DM and fed twice daily. Commercial calf starter was offered from 3 d of age. When milk replacer was fed at 5% of BW from 29 to 35 d, BW gain was reduced compared with that of calves on the other treatments; however, BW at 56 d was unaffected by treatment. Concentrations of NEFA and blood urea N were higher from 29 to 56 d than when calves were fed milk replacer at 5% of BW from 29 to 35 d. Blood BHBA increased as starter DMI increased and was unaffected by treatment. Intake of milk replacer and feed cost were greater for calves that were weaned when calf starter intake reached 454 g/d for 2 consecutive d. For calves that were weaned according to intake, mean age at weaning was 40 d.