Supplementation of feed block containing different levels of U-cas inclusion influenced on the intake of rice straw, total feed and energy in Thai native beef cattle. Feed block intake was similar among cattle in the present study and was at 0.3 kg/d and this indicated that U-cas can replace urea in feed block for Thai native beef cattle without adverse intake. The feed block intakes in the present investigation were similar to Foiklang et al. (2011) who reported that the range of feed block intake of swamp buffalo were from 0.27 to 0.31 kg/d.