Results and discussions
The energy balance including the results of the metabolism trial in Thai native beef cattle are shown in Table 1. The GE, DE and ME intake and heat production on the basis of metabolic body size was higher in T3 (P0.05) among the treatments. The results indicated that heat production increased as ME intake increased. Especially, animals fed T3 was higher efficiency of feed utilization than T1 and T2, because compensatory growth was the ability of animals to exhibit after feed restriction (Hornick et al., 1998) A significant linear relationship between metabolizable energy intake (MEI) and energy retention (ER) were obtained; ER = (0.6379(SE = 16.46) x MEI) - 345.30(SE = 0.03), (R2 = 0.955; P