Concentrations of plasma Met (A), Lys (B), and His (C) concentrations after rumen-protected methionine (RPM) top-dressing for CON (●; n = 2 composite samples from 8 cows) or RPM (○ n = 3 composite samples from 12 cows). For Panel A, there was an effect of treatment (P < 0.001), time (P < 0.001), and an interaction of treatment x time (P = 0.002). For Panel B, effect of treatment (P = 0.99), time (P = 0.08) and the interaction of treatment x time (P = 0.71). For Panel C, effect of treatment (P = 0.85), time (P = 0.001) and the interaction of treatment x time (P = 0.03). An asterisk (*) indicates that mean values differ (P < 0.05) within a specific time. A tendency is indicated by a dagger (†) (0.05 < P ≤ 0.10).