The effects of various herb supplementation in the concentrate diet on rumen fermentation and blood metabolites are presented in Table 2. The results showed that ruminal pHs were not affected by herb supplement and were at pH = 6.5 to 6.9. However, there was a tendency to increase ruminal pH as animals were supplemented with herds (p = 0.06), especially in herb combination treatment (LPG). On the other hand, ruminal NH3-N and BUN concentration were significantly decreased by herb supplements (p0.05) in total VFA and C4 concentration when animals were supplemented with and without herbs. In contrast, while C2 concentration was significantly decreased by herb supplementation (p = 0.02), C3 concentration was slightly increased (p = 0.04). As a consequence, the C2:C3 ratio was decreased in herb supplementation. In addition, based on the calculation, methane production (CH4) was lower in herb supplemented treatments as compared to control (p = 0.04) and tended to show the lowest value in the herb combination group (LPG = 27.9 ml/100 ml) (p = 0.05).