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Lactation initiation involves coordinated changes in several tissues, including muscle protein mobilization to meet the cow's amino acid requirements. The present study was conducted to investigate the effect of the protected amino acids lysine and methionine in pre- and post-partum diets on protein performance and dynamics in the post-partum period. Twenty-one Holstein cows (7 replicates per treatment) were randomly assigned to three diets from 28 days before calving to 28 days after calving. The experimental treatments were: control diet, amino acid diet; Balanced for the amino acids methionine and lysine protected at the level of the latest recommendations and high protein diet balanced for the above methionine and lysine using soybean meal, canola meal and corn gluten meal. Consistent with the results, dry matter consumption, body weight and thickness of muscle and fat tissue were higher in the amino acid and high protein treatments compared to the control group (P<0.05). The muscle tissue breakdown index, 3-methylhistidine of milk, was higher in the control treatment compared to amino acid and proprotein treatment (P<0.01), but 3-methylhistidine was lower in aminoacid treatment cows compared to proprotein treatment (P<0.01). In general, it seems that the addition of limiting amino acids lysine and methionine to the diet of cows during the transition period not only leads to the improvement of feed consumption and production performance, but also is effective in preventing the excessive breakdown of protein and fat tissue during the postpartum period. [ABSTRACT FROM AUTHOR]