Pre- and post-weaning performance and health of calves fed 24% crude protein and 20% fat milk replacer at different feeding rates

Abstract Text: In our previous work, calves fed greater amounts of milk replacer (MR) and CP demonstrated improved growth.  The current study was to evaluate the pre- (d 1 to 42) and post- (d 43 to 56) weaning performance and health of calves fed a 24% CP and 20% fat MR at different feeding rates (FR).  One-hundred four (1-5 d of old) individually fed Holstein heifer calves (40 ± 0.69 kg) were randomly assigned to 1 of 4 treatments in a randomized complete block design. The same all milk MR was fed at 14.7% solids with treatments being 1) Control (MR57): MR fed at 0.284 kg in water twice daily for 35 d; 2) MR71: MR fed at 0.34 kg twice daily from d 1 to 7 and at 0.34 kg twice daily from d 8 to 35; 3) MR85: MR fed at 0.34 kg twice daily from  d 1 to 7 and at 0.43 kg twice daily from d 8 to 35: and 4) MR99: MR fed at 0.34 kg twice daily from d 1 to 7 and at 0.497 kg twice daily from d 8 to 35.  All treatments were fed once daily MR from d 36 to weaning at d 42 with water and an 18% CP texturized calf starter (CS) offered free choice. Pre-weaning and overall ADG (0.78, 0.82, 0.83 and 0.85 kg/d for MR57, MR71, MR85, and MR99, respectively) were higher (P < 0.05) for MR99 calves vs. MR57 calves with other calves being intermediate.  Overall d 1 to 56 CS intakes were higher for MR57 calves vs. other calf groups. There were no differences (P > 0.05) in total DMI. Pre-weaning gain/feed was lowest (P< 0.05) for MR57 calves.  Gain/feed d 1 to 56 (0.49, 0.52, 0.52 and 0.54 kg/kg DM) was higher for MR99 vs. MR57 calves with other calves being intermediate. This study demonstrated that feeding higher FR of a 24:20 MR resulted in higher ADG’s and feed conversions (gain/feed).

Keywords: milk replacers, feeding rate, calf performance