This experiment was conducted to study the effects of supplementing the total mixed ration (TMR) containing oil palm frond (OPF) silage with different levels of enzyme on feed intake and growth performance of goat. Twenty four post-weaning Boer × Thai Native crossbred male goats with initial body weight (BW) of 11-18 kg, were arranged to receive four dietary treatments in a randomized complete block design. The diet used in the study contained 60% oil palm frond silage and 40% concentrate. The enzyme mixture produced by Aspergillus spp. BCC 274, containing approximately 1×10⁷, 9×10⁶, 2×10⁶, 1×10⁶ and 2×10⁶ unit/kg dry weight for xylanase, β-glucanase, cellulase, mannanase and amylase, respectively, was supplemented to the concentrate portion at 0, 2, 4 and 6 g/kgDM of the TMR. The results showed that the supplementation of enzyme to the TMR did not affect (P>0.05) dry matter intake (DMI). Goats receiving TMR supplemented with enzyme at 2 g/kgDM tended to have higher ADG and better feed per gain ratio as compared with other treatments. Coefficient of DM digestibility of TMR was not significantly affected by the enzyme supplementation. In addition, there were no significant differences (P>0.05) among treatments regarding, average NH ₃-N concentration, the amount of C₂, C₃ and C₄ in the rumen fluid and BUN concentration. However, overall mean of ruminal NH 3-N concentration was significantly lower in goat receiving TMR supplemented with enzyme at 2 g/kgDM than that of goat receiving TMR with no enzyme supplementation (P<0.05). Based on this experiment, the application of enzyme at 2 g/kgDM in TMR containing OPF silage could increase ruminal availability of slowly digestible carbohydrate and improve goat performance.