the number of dairy cows is dramatically increasing in Northeast Thailand in the last decade. However, the milk yield is still low (average 9.4 kg per day, Udchachon et al., 1996). although there are complex reasons for the low milk yield, one of the main reasons would be a problem of feed. the situation is worsened in the dry season, as the production system highly relies on rice straw as roughage. although urea treatment of rice straw has been promoted for dairy farmers, the adoption of by farmers is still very low (Udchachon et al., 1996).