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Two experiments were conducted to observe the effects of direct fed microbials on metabolic characteristics in sheep and milking performance in dairy cows. A metabolic trial with four ruminally cannulated sheep (60±6kg) was conducted in a 4×4 Latin square design to investigate the supplementation effects of Saccharomyces cerevisiae, Clostridium butyricum or mixed microbes of S. cerevisiae and C. butyricum on ruminal fermentation characteristics and whole tract digestibility. Sheep were fed 1.25 kg of total mixed ration (TMR, DM basis) supplemented with S. cerevisiae (2.5g/day), C. butyricum (1.0g/day) or its mixture (S. cerevisiae 1.25 g/day + C. butyricum 1 g/day), twice daily in an equal volume. But control sheep were fed only TMR. A feeding trial with 28 lactating Holstein cattle was also conducted for 12 weeks to investigate the effects of the same microbial supplements as for the metabolic trial on milking performance. The cows were fed the TMR (control), and fed S. cerevisiae (50 g/day), C. butyricum (15 g/day) or its mixture (S. cerevisiae 25 g/day + C. butyricum 7.5 g/day) with upper layer dressing method.Total VFA concentration and the digestibility of whole digestive tract in the sheep increased by supplementation of S. cerevisiae, C. butyricum or their combined microbials compare to control group. The proportion of propionic acid at 1 h (P<0.039) and 3 h (P<0.022) decreased by supplementation of S. cerevisiae while tended to increase acetic acid proportion at the same times.Daily dry matter intake (DMI) was not influenced by the microbial treatments, but milk yield (P<0.031) and feed efficiency (milk yield/DMI, P<0.043) were higher for the cow received C. butyricum than those for other treatments. The milk fat content was higher (P<0.085) when cows fed S. cerevisiae (4.11%) than that fed the control (4.08%), the diets with C. butyricum (3.85%) and the microbial mixture.Based on the results obtained from the current experiments, supplementation of C. butyricum or mixture with S. cerevisiae might be increased milk fat content and milk productivity of lactating daily cows.