Methods of reducing milk replacer to prepare dairy calves for weaning when large amounts of milk replacer have been fed

Abrupt weaning of calves fed over 0.7 kg DM of milk or milk replacer (MR) has reduced ADG in calves by depressing starter intake in numerous trials and laboratories. We compared different gradual weaning programs in two 56-d trials. In trial 1, a 27% CP, 17% fat MR fed at 0.66 kg DM/d for 42 d (LO) was compared with the same MR fed at 0.88 kg/d for 21 d and reduced 0.66 kg/d for 21 d before weaning (HI) and a 22% CP, 27% fat MR fed at 0.79 kg/d for 21 d and changed to the 27% CP, 17% fat MR fed at 0.66 kg/d for 21 d before weaning (HIFAT). Calves fed HI had greater ADG and similar starter intake compared with calves fed LO, whereas calves fed HIFAT had lower starter intake and ADG compared with calves fed LO. In trial 2, a 27% CP, 17% fat MR was fed at 0.66 kg DM/d for 42 d (LO), fed at 0.96 kg/d for 21 d and reduced to 0.66 kg/d before weaning over 21 d (HI), and fed at 0.96 kg/d for 28 d and more gradually reduced compared with HI over 14 d before weaning (HIGRAD). Calves fed both HI and HIGRAD had greater ADG and similar starter intake to calves fed LO. Weaning calves over 14 to 21 d that had been fed MR at 0.88 kg DM or more did not result in reductions in ADG and starter intake.