The optimum ratios of protein, fat, and limiting amino acids for milk replacers fed to young dairy calves were described in the July 2009 issue of the Journal of Dairy Science. In milk replacer powders fed at 1.25 pounds per head daily (approximately 5 quarts of liquid replacer daily), body weight gain was maximized with powders containing 24 percent protein, 17 percent fat, 2.18 percent lysine, and 0.66 percent methionine. However, in milk replacer powders fed at 1.5 pounds per head daily (approximately 6 quarts of liquid replacer daily), body weight gain was maximized with 26 percent protein, 17 percent fat 2.32 percent lysine, and 0.72 percent methionine. It also was reported that lowering the protein of the powder fed at 1.5 pounds per calf daily, while maintaining similar concentrations of lysine, methionine and threonine, would not maintain body weight gain. This shows that other amino acids likely became limiting to growth when the protein is reduced. These data support findings published last year in the Journal of Dairy Science reporting that milk replacers supplemented with lysine and methionine supported approximately 15 percent more body weight gain than unsupplemented milk replacers. In that research calves fed 24 percent protein milk replacers supplemented with lysine and methionine gained as much body weight as calves fed 28 percent protein milk replacers. Two to 4 percentage units of milk protein in milk replacer powder greatly affect the cost of the powder. However, correctly supplementing a milk replacer with synthetic amino acids can either maintain or increase body weight gain by approximately 15 percent while lowering the cost per unit of body weight gain. This research was conducted at the Akey Nutrition and Research Center.
Click here to access the abstract from the Journal of Dairy Science.