The pattern of ruminal fermentation and overall means are presented in Table 2. Ruminal
temperature and pH were similar among treatments and the values were quite stable at 39.1-39.4°C and
pH 6.2-6.4, which was within the range (pH 6.0-7.0) considered for optimal microbial digestion of fibre
and protein [7]. Ruminal NH3-N, BUN and MUN ranged from 13.7-19.0, 11.3-15.7 and 13.5- 15.9
mg/dL respectively. Ruminal NH3-N and BUN concentrations were lower in CH and YEFECAP than in
SBM and LL. It was reported that ruminal NH3-N concentration increased linearly with increasing
supplemental RDP levels [6]. Therefore, a possible explanation for this could be that SBM and LL
contain a high level of RDP, which leads to a high ruminal NH3-N. Using the in sacco method, Promkot
and Wanapat [5] found that effective degradability of CP in SBM and LL was higher than that found in
CH. Wanapat [8] also reported that cattle fed on CH (250 g CP/kg) had lowered rumen NH3-N and
BUN concentration, which demonstrated the effect of condensed tannins in CH on the formation of
tannin-protein complexes which in turn could enhance the cattle’s rumen by-pass protein.