Production performance and safety of meat from beef cattle finished in feedlots using salinomycin in the diet

This study assessed production performance, carcass characteristics, serum parameters, residue depletion of meat, and economic performance during the finishing period of steers in feedlots using salinomycin in their diet. A total of 32 steers were finished in a feedlot on a diet comprising corn silage and concentrate (50: 50), with or without added salinomycin (120 mg per animal day(-1)). Study design was completely randomized, with eight repetitions. Results indicated that the use of salinomycin increased both weight gain (1.582 vs. 1.304 kg) and feed conversion (6.16 vs. 7.25 kg kg(-1)). No significant alterations were observed in feed intake (9.52 vs. 9.25 kg animal day(-1)), serum parameters, or apparent diet digestibility. The withdrawal period of 16 h prior to slaughter promoted a lower salinomycin concentration (0.25 mu g kg(-1)) in organs and edible tissues, which is below the levels allowed by legislation. Animals finished with salinomycin also exhibited greater warm carcass weight (287.76 vs. 275.81 kg) and better economic performance (profit margin increments of R$ 84.20 per animal). Salinomycin use in feedlot-finished steers promoted both production and economic performance improvements without added implications to either animal or consumer health since there were no significant residues found in any edible tissues.