Effect of Consistency of Nutrient Intake from Milk and Milk Replacer on Dairy Calf Performance

The effect of variable nutrient concentration in the liquid diet and variable intake of nutrients on ADG and feed efficiency of neonatal dairy calves was evaluated. Three treatments were fed in trial 1 that all provided 0.418kg DM/d. Treatment A was a 21% CP, 21% fat milk replacer (MR) powder. Treatment B was half DM supplied by the MR from treatment A and half DM from whole, saleable milk. Treatment C was all raw milk. In trial 2, two MR were fed at either a variable daily rate (0.525 to 0.788kg DM/d) or a fixed daily rate (0.653kg DM/d) to provide an average of 0.653kg DM/d in 4 treatments. The MR were either 27% CP and 31% fat (to simulate Holstein milk) or 27% CP and 17% fat. In trial 1, preweaning ADG, starter intake, feed efficiency, hip change, and BCS change were greater for calves fed treatment A vs. B and C. In trial 2, preweaning ADG and feed efficiency were less for calves fed the 31 vs. 17% fat MR. Calves fed the fixed rate of MR had greater ADG, starter intake, and efficiency than calves fed the variable rate of MR. Calves fed a consistent diet had greater ADG, starter intake, and feed efficiency than calves fed an inconsistent liquid (milk or MR) diet. Milk had more variation and greater concentrations of nutrients and bacteria than MR. A MR offers better potential to provide a consistent diet than milk.