Among the purine derivatives, excretions of xanthine plus hypoxanthine, and allantoin were similar (P>0.10) for all groups ( Table 7). However, uric acid excretion in the T3 group significantly increased compared with control and T2 group. Total PD excretion and absorption and purine derivative N index were similar for all the treatments. Microbial N supply tended to be greater for T3 than T2; however, this was similar for treatment groups with respect to control. Microbial N supply in terms of digestible OM intake or digestible OM fermented in the rumen did not differ among all the groups.