in Table 3. Mean ruminal pH of treatments ranged from 5.87 to 5.98, but was not significantly different among treatments. Ruminal fluid concentration of NH3-N was not affected by EO supplementation. The mean concentration of total VFA in experimental treatments ranged from 109 to 112 mM and was similar in all dietary treatments. Conversely, proportions of acetate, propionate and butyrate were influenced by treatments. Supplementation of THY and CIN decreased (p