The study aimed to assess the effect of fermented total mixed ration (FTMR) on the in vitro nutrient digestibility and ruminal fermentation patterns. The experiment was arranged in a completely randomized design with 3 treatments corresponding to three FTMR formulas: FTMR1, FTMR2, and FTMR3. It was found that the digestibility of dry matter, organic matter, and neutral detergent fiber showed no significant differences (P>0.05) among the treatments at 24, 48, and 72h post-incubation. However, the digestibility of crude protein showed significance (P0.05). Regarding individual VFA proportions, no changes were seen in acetic, butyric, and propionic from 0 to 3 hours of incubation, but variations appeared at 24h. In summary, varying FTMR formulas did not affect nutrient digestibility and ruminal fermentation patterns.