Blood parameters and performance in steers feedlot subject to different ionophores sources

Abstract

The present study was conducted to evaluate blood glucose and urea concentrations and estimate performance of 36 castrated Nelore steers, in feedlot during 100 days of experiment. Treatments utilized were: 1) control (no ionophore), 2) 44mg of lasalocid/kg of concentrate in dry matter and 3) 44mg of monensin/kg of concentrate in dry matter. As forage, it was used Coast-Cross (Cynodon dactylon) hay, in 30% of total ration. After 35 days of experiment, the dry matter intake decreased in monensin group, with –6,5% and –5,9%, for control and lasalocid groups. There were no effects of monensin and lasalocid supplementation in blood glucose and urea concentrations, no effects in daily gain, feed efficiency, carcass dressing percentage, rib eye area and subcutaneous fat thickness through the experiment. The concentration of 44mg/kg of ionophores in termination steers rations did not change the energy and protein metabolism and improved the weight gain as well carcass characteristics in Nelore steers in feedlot.