Effects of Feeding Calves Different Rates and Protein Concentrations of Twenty Percent Fat Milk Replacers on Growth During the Neonatal Period

Three trials were designed to examine how the feeding rate of a 20% fat milk replacer (MR) affected calf performance. Holstein bull calves (40 to 41 kg average initial BW; < 7 d) were randomly assigned to MR treatments and fed fixed amounts of MR with free-choice starter for 42 d. Calves were weaned at 42 d and fed starter only from d 43 to d 49. A 20% CP, 20% fat MR fed at 0.45 kg daily served as the control treatment in each trial. Feeding a 28% CP, 20% fat MR stepped-up to 1.13 (Trial 1) or 1.36 (Trial 2) kg daily resulted in similar BW gains, increased fecal scores, increased medical treatments (52 to 72%), and reduced starter intake (48%) by 49 d compared to the control. Feeding a 28% CP, 20% fat MR at 0.68 kg daily (Trial 3) increased BW gains (55%) and tended to increase fecal scores and medical treatments (27%), but tended to decrease starter intake (11%) vs. the control by 49 d of age. Feeding a 20% CP, 20% fat MR at 0.68 kg daily (Trial 3) did not increase daily gains, but tended to decrease starter intake (14%) vs. the control by 49 d of age. Increasing the CP level above 20% (to 28% in this case) was needed to promote BW gains when the MR feeding level was increased to 0.68 kg.