Enzymatic Complex In Diets Containing Monensin Or Essential Oils To Nellore Bulls In Feedlot System

The aim was to evaluate the effect of multi-enzymatic complex (MEC) addition on the performance of Nellore bulls fed diets containing Monensin or Essential Oils (EO). One thousand and twenty four bulls (IBW=410 +/- 31 kg) were distributed into 32 pens, and a randomized complete block design was adopted. The treatments were diets with: monensin (30 mg/kg DM); monensin + MEC (0.25 g/kg DM); EO (0.8 g/kg DM) and EO + MEC. Cattle fed monensin consumed less feed (adaptation and total period), had greater ADG during adaptation and same ADG during the total period and greater FE (adaptation and total period) than cattle fed EO. Cattle fed MEC presented greater final body weight (FBW) and ADG at the end of the adaptation period. No differences were observed for HCW and carcass dressing from different treatments at the end of the experiment (P>0.05). The animals fed MEC presented greater DMI (% BW) during the adaptation period, compared to those that did not receive it. MEC utilization improve weight gain during the feedlot adaptation period. Monensin improved FE during feedlot total period.