Development of a modified accelerated milk replacer feeding program through 8 weeks of age
Our previous studies have demonstrated that a modified accelerated milk replacer (MR) having a 24:20 crude protein (CP):fat concentration fed at higher feeding rates (FR) resulted in improved growth performance and gain/feed, but not linearly. The current study was to evaluate pre- (d 1-42) and post-weaning (d 43to 56) calf performance when modified accelerated MR was fed at higher FR compared to a MR having similar or higher CP and lower fat concentrations. One-hundred thirty (1 to 6 d old) fed Holstein heifer calves (40.1±0.76 kg) were blocked by birth date and randomly assigned to 1 of 5 treatments. Treatments of MR fed at 14.7% solids were: 1) Control (C): all milk 24:20 MR fed at 0.26 kg at 2x/d from d 1 to 35; 2) C+: C MR fed at 0.32 kg 2x/d from d 1 to 35; 3) LF: CP and low fat (24:16) MR fed at 0.32 kg 2x/d from d 1 to 35; 4) LF+: LF MR fed at 0.32 kg 2x/d from d 1 to 7 and at 0.39 kg from d 8 to 35; and 5) HP+: High CP:LF MR (26:16) fed at the rates of LF+. All MR were fed 1x/d from d 36 to weaning at d 42 with water and 18% CP texturized calf starter (CS) offered free choice from d 1 through 56. Calves fed C+ had greater (P < 0.05) ADG (0.71, 0.75, 0.70, 0.72, and 0.72 kg/d for C, C+, LF, LF+, and HP+, respectively) from d 1 to 56 compared to calves fed LF, with other treatments being intermediate. Calves fed C+, LF, and HP+ were similar, but taller at the hips (P<0.05) than calves fed C and LF+ (98.1, 99.6, 99.8, 98.5, and 99.8 cm). However, calves fed C+ had greater hip widths on d 56 (22.3, 22.6, 21.7, 21.8, and 22.3 cm) and on d 84 (26.2, 26.5, 26.0, 26.2, 26.4 cm) than calves fed LF with other treatments similar. This study demonstrates that feeding a modified accelerated MR (24:20) at a moderate FR improves ADG and frame measurements compared to calves fed MR having similar or different CP and fat concentrations. The development of a modified accelerated feeding program optimized the protein energy ratio for the potential of producing a dairy heifer with a frame that is taller and wider without having a weaning slump.
Keywords: Milk Replacer, protein Concentration, fat concentration.