Amino acid nutrition of the young calf. Estimation of methionine and lysine requirements.

A semipurified diet containing 14 crystalline amino acids as the sole source of nitrogen was used qualitatively and quantitatively to determine dietary needs of the young calf for lysine and methionine. Body weight gain, nitrogen balance, and concentrations of free amino acids in plasma were the criteria to assess the response of young calves to the experimental diets containing graded amounts of lysine and methionine. By these methods the methionine requirement as D-L methionine in the absence of cystine ranged from .17 to .23 g/day/kg body weight (.65 g/kg weight.75).