Table 4 Mean total VFAs and propionate concentrations in the rumen were significantly different by increased with receiving YMFCC(T2)than T1 (117.6 and 102.4mM) However,it was found that total VFA concentration in all diets ranged from 70-130 mM, the range suggested by France and Siddons (1993) Especially,the acetate to propionate ratio was decreased by receiving YMFCC (T2) than T1 (2.7 and 4.1) but the supplementation of YMFCC (T2) increased the daily output of propionate without decreasing the production of acetate (23.9 and 17.8 mol/100 mol) and it was in agreement with the results reported by Callaway and Martin (1996>and Khampa et al (2006)