2.1. Animals, housing and diets This experiment was approved by the Department of Animal Production at the State University of Maringá (CIOMS/OMS, 1985). Forty Purunã bulls (¼ Aberdeen Angus + ¼ Caracu + ¼ Charolais + ¼ Canchim) were used in a completely randomized design and allocated into individual pens (8 m2for each animal). After an 11-d diet adaptation period, the bulls were weighed and started the study with an average initial BW of 209 ± 33.3 kg and an average age of 8 ± 0.9 months. The bulls were assigned to diets containing glycerine at 0, 60, 120 or 178 g/kg DM; which replaced 0, 183; 385; and 613 g of corn per kg of diet, respectively. The experimental period in a feedlot system was 229 days