ABSTRACT The objective was to evaluate the effects of corn silage supplemented with 1-propanol or inoculated with L. buchneri on the ruminal fermentation profile, digestibility, and production traits of lactating Holstein cows. Whole-corn plants were harvested at 350 g/kg dry matter (DM) and packed in nine bag silos (13 t/silo). At ensiling, two treatments were applied: control (no additive; six silos) and L. buchneri inoculation with 1 × 105 cfu/g (three silos). Feeding started after 247 days of storage; one L. buchneri and two control silos were opened in each experimental period. Twenty-one multiparous Holstein cows (~33 kg/day of milk) were allocated to seven balanced 3 × 3 Latin squares with 21-day periods (14 days of adaptation). The experimental diets contained (DM basis): 80 g/kg cottonseed, 95 g/kg citrus pulp, 180 g/kg soybean meal, 90 g/kg corn grain (ground), 25 g/kg minerals and vitamins premix, and 530 g/kg of corn silage. Source of corn silage was the only difference between experimental treatments: control, L. buchneri, or control silage supplemented with 1-propanol (10 g/kg of diet DM). The 1-propanol was dissolved in water (1:1) and sprinkled onto the ration during mixing, immediately before each feeding. Dry matter intake, nutrient digestibility, milk yield, and composition were not affected by treatments. Cows fed 1-propanol had greater concentrations of 1-propanol in the rumen fluid, higher concentration of glucose, and lower concentration of non-esterified fatty acids in blood plasma. Corn silage inoculated with L. buchneri at 1 × 105 cfu/g does not affect silage fermentation, ruminal fermentation profile, or milk production. Supplementation of 1-propanol at 10 g/kg affects the ruminal fermentation profile without affecting feed intake and milk production of mid-lactating dairy cows.