The DM content of all supplements was similar (885-895 g/kg fresh weight), and the N contents of RTPP, LLRT, CLRT and MLRT supplemental diets were quite similar (19.9-21.4 g/kg DM).
As shown in Table 2, the apparent whole tract digestibility of DM and OM was higher (p<0.05) in cattle consuming the CLRT supplement (0.55, 0.58) than in those supplemented with RTPP (0.52, 0.54), LLRT (0.52, 0.55) and MLRT (0.51, 0.54).
As shown in Table 3, N intake was similar in cattle fed LLRT, CLRT and MLRT supplements (1.238, 1.253 and 1.249 g N/kg [BW.sup.0.75]/d, respectively), but was lower in animals fed the RTPP supplement(1.184 g N/kg [BW.sup.0.75]/d).
Urinary allantoin excretion of cattle supplemented with LLRT (0.654 mmol/kg [BW.sup.0.75]/d) and CLRT (0.593 mmol/kg [BW.sup.0.75]/d) was not different (see Table 4).
There were also no differences in plasma [beta]-HBA and insulin concentrations in cattle fed LLRT, CLRT and MLRT supplemental diets.
NDF digestibility was also lower in cattle supplemented with LLRT than in animals fed CLRT and MLRT supplements, though the quantity of N intake in the rumen was not different.
Similarly, NDF digestibility was observed in animals fed with CLRT and MLRT supplements, but the intake of condensed tannins in animals fed CLRT and LLRT was not different.
N balance was greater in cattle fed LLRT, CLRT and MLRT supplemental diets than those fed RTPP.