The objective of the experiment was to evaluate the feedlot performance of 5/8 Nellore-3/8 Charolais steers slaughtered at 425, 467 and 510 kg. The steers presented at the beginning of the confinement average age of 660 days, live weight of 361 kg and body condition score of 2.9 points. The animals were fed with a 60:40 roughage:concentrate diet, containing 10.25% of crude protein (CP), 72.18% of total digestible nutrient (TDN) and 3.18 Mcal of digestible energy (DE)/ kg of DM. The time necessary for the animals reach the slaughter weight (P) was 30, 65 and 94 days, respectively. The daily average intake of DM, TDN, DE, CP, NDF and ADF expressed per animal, 100 kg of live weight and metabolic weight did not show a significant relationship with slaughter weight. Average daily weight gain (ADG) declined as the slaughter weight increased (ADG=4.939-0.007P), being the average values of 2.10, 1.68 and 1.56 kg, respectively, for the three slaughter weights. There was a significant relationship between slaughter weight and final body condition score (FBC=0.658+0.008P) and daily gain in BC (DGBC=-2.684+0.008P). The food conversion of the DM,TDN,DE and CP intake into weight gain, increased linearly as the slaughter weight increased (CDM=-5.644+0.025P; CTDN=-4.074+0.0187P; CDE=-17.925+0.079P; CCP=-0.578+0.003P), showing that the feed efficiency declined. However, the food conversion can be considered satisfactory, respectively, 4.75, 5.97 and 6.75 kg of DM consumed/kg of weight gain.
feed conversion; feed intake; slaughter weight; weight gain
