Effects of adding arginine and histidine to dairy calf milk replacers

Male Holstein calves, 2 to 3 d of age, were fed a 27% CP (whey based), 17% fat milk replacer (MR) at 0.66 kg of DM per calf daily to provide control or test treatments with either added l-Arg or l-His. Calves were also fed free choice corn, oat, and soybean meal-based starters and water. Each trial included an unsupplemented control and supplemented test MR. In trial 1, MR contained 0.28 and 0.44 Arg-to-Lys ratios. In trial 2, MR contained 0.27 and 1.0 Arg-to-Lys ratios. In trial 3, MR contained 0.2 and 0.42 His-to-Lys ratios. Measurements included ADG, feed efficiency, starter intake, hip width, and serum preweaning concentrations of albumin, alkaline phosphatase, amylase, creatinine, glucose, total protein, and urea N. Data from each trial were analyzed as repeated measures over time during preweaning (0 to 42 d in trials 1 and 2 and 0 to 28 d in trial 3), postweaning, and overall 56-d periods. Other than increases (P < 0.05) in test Arg and His intake, no measurements in any trial differed (P > 0.1). The lack of response to supplementing Arg and His to young dairy calves indicates that Arg and His in these whey protein-based MR were not limiting to normal growth and performance.