The study objective was to determine if feeding a rumen degradable AA can increase milk production comparable to growth hormone (GH). Eight multiparous late-lactating (255 ± 26.4 d in milk) Holstein dairy cows were blocked by milk yield (34.1 ± 8.25 kg/d) and randomly assigned to 1 of 4 treatments in a replicated 4 × 4 Latin square design having 21 d periods with 7 d for dietary adaptation and 14 d for data collection. Treatments were control (C), Posilac (rBST), and valine fed at 40 (V40) and 80 g/d (V80). Cows were fed a total mixed ration (TMR) with a distillers grains carrier at 113.4 g/d containing none or added AA. Rumen and blood samples were collected during wk 2 and 3 for volatile fatty acids and endocrine assays. Dry matter intake was similar (P > 0.10) (21.3, 22.0, 22.8, and 21.5 kg/d for C, rBST, V40, and V80, respectively) for cows receiving all treatments, but milk yield (22.0, 26.1, 25.2, and 24.9 kg/d), FCM (22.1, 25.4, 24.4, and 24.3 kg/d), and ECM (22.7, 26.1, 25.1, and 24.9 kg/d) were significantly (P < 0.05) increased for cows receiving rBST, V40, and V80 compared with C cows. Milk yield improvements were similar (P > 0.10) between rBST, V40, and V80. Milk fat percentages (3.51, 3.36, 3.32, and 3.38%) were highest (P < 0.05) for cows receiving C compared with cows receiving V40, while cows receiving other treatments were intermediate and similar (P > 0.10). Milk protein percentages (3.20, 3.12, 3.15, and 3.13%) were greatest (P < 0.05) for cows receiving C compared with cows receiving rBST. Ruminal isobutyric acid (1.01, 1.05, 1.28, and 1.49 molar %) concentrations were increased (P < 0.05) for cows receiving V40 and V80 compared with cows receiving C and rBST treatments. Plasma IGF-1 concentrations (60.4, 106.1, 65.9, and 58.3 ng/mL) were greater (P < 0.05) for cows receiving rBST compared to cows receiving other treatments. Plasma GH concentrations (1.78, 1.99, 1.55, and 1.45 ng/mL) were greater (P < 0.05) for cows receiving rBST compared with V40 and V80 cows, while C cows were intermediate and similar (P > 0.10). This study suggests that feeding a rumen degradable AA can increase milk yield comparable to rBST.