The work was conducted to evaluate the effect of the supplementation with corn silage on the performance of finishing cull cows under oat (Avena strigosa) plus ryegrass (Lolium multiflorum) temporary grazing. The corn silage used was AG-5011 hybrid, containing 6.59% of crude protein. Thirty ¾ Charolais (C) ¼ Nellore (N) or ¾ N ¼ C culls cows with average of age of 5 years, were used, receiving or not a corn silage offer of 1.25% of live weight (dry matter) or an "ad libitum" offer. No interaction between genetic group and offered supplementation was observed. Animals that had received "ad libitum" corn silage presented greater absolute supplementation intake (4.57 against 4.34kg), disappearing this difference when the intake was expressed in percentage of the live weight (1.07 against .99%). The cows that received supplementation presented greater average daily weight gain (GMD) in comparison to those that did not (.879kg), independent of the offered level. Silage "ad libitum" offer did not provide greater GMD (1.175kg) in relation to those that received 1.25% of live weight (1.214kg). The higher silage intake provided greater final body condition (3.42 points), being the cows that received 1.25% of live weight (3.26 points) had no difference from those that received any supplementation (3.19 points). The ¾ C ¼ N cows presented greater absolute supplementation intake (3.05 versus 2.89kg), greater GMD (1.196 against .983kg/animal/day) and greater body condition at the end of the experiment (3.37 versus 3.21 points).
oat; ryegrass; Charolais; Nellore; roughage
