We aimed to evaluate the effect of exogenous amylase and essential oils (EO) fed to cross-breed dairy cows. Thirty-nine lactating Holstein × Gyr cows (75 ± 34 DIM, 502 ± 57 BW) were distributed into 3 treatments and evaluated for 49 d. Treatments were: monensin (15.8 mg/kg of DM); monensin + amylase (15.8 mg/kg of DM monensin and 658 mg/kg of DM Ronozyme RumiStar, DSM Nutritional Products Brazil SA) and EO + amylase (52.7 mg/kg of DM CRINA Ruminants and 658 mg/kg of DM Ronozyme RumiStar; DSM Nutritional Products Brazil SA). Diet composition was 467 g/kg DM of concentrate, 480 g/kg DM maize silage and 53 g/kg DM Tifton hay. Chemical diet composition was: 192 g/kg CP, 300 g/kg NDF, and 249 g/kg starch. Four open-circuit respirometry chambers were used for the energy evaluation, CH₄ production (g day⁻¹), yield (g kg DM⁻¹, NDFI⁻¹ and NDFD⁻¹) and intensity (g kg ECM⁻¹). Blood sampling was performed 4 h after morning feeding. The experimental design was completely randomized. Treatment effects were tested using ANOVA (SAS), and means were compared by LSM at P < 0.05. Energy partitioning, energy efficiency, and the CH₄ total production (g/d) were similar for all treatments. The CH₄ yield per unit of neutral detergent fiber intake increased (7.1%) with the amylase addition into a diet with monensin, and reduced (14.5%) when monensin was replaced by EO (65.1, 70.1 and 59.9 g/kg NDFI for treatments monensin, monensin+amylase, EO+amylase, respectively; P = 0.017). The CH₄ yield in grams per unit of neutral detergent fiber digestible was increased for the treatment monensin+amylase in comparison to monensin and EO+ monensin treatments (132, 113 and 114 g/kg NDFD, respectively; P = 0.028). The replacement of monensin by EO reduced the nonesterified fatty acids blood concentration (NEFA, 0.40 vs 0.55 mmol/L) and did not change the values of glucose, urea, triglycerides and d-3-hydroxybutyrate. The EO as alternative to monensin for lactating dairy cows did not affect CH₄ production or intensity, had no effect on energy efficiency use and decreased NEFA concentrations.