Comparison of the β-agonists Actogain 45 and Optaflexx on finishing steer performance and carcass characteristics

A total of 2,576 steers allotted to 24 pens were used to evaluate 2 forms of ractopamine, Optaflexx (Elanco Animal Health, Greenfield, IN) or Actogain 45 (Zoetis, Florham Park, NJ) brands of ractopamine hydrochloride, on steer performance and carcass traits (12 pens; 1,288 steers per treatment). Both test articles were fed at a rate of 16.4 g/t (DM basis) to target a consumption of 210 mg per head for an average (range 28 to 31) of 30 d. Total gain, daily gain, and feed efficiency tended (P < 0.10) to favor Actogain 45 on a live basis. However, there were no significant differences (P ≥ 0.32) between treatments for carcass-adjusted total gain, daily gain, or feed efficiency. Furthermore, there were no differences for estimated total carcass gain or rate of carcass gain (P ≥ 0.34). Finally, there were no differences (P ≥ 0.29) in HCW or any carcass USDA YG or QG variables. There was no evidence of lameness or locomotion impairment in any steer during the course of this study or at time of slaughter. It was concluded there were no differences between Optaflexx and Actogain 45 on performance or carcass traits of steers when fed at a rate of 16.4 g/t (DM basis) for the final 30 d on feed.