Our objectives were to evaluate the benefits of yeast cell wall (YCW) supplementation on performance, carcass characteristics, and tenderness of steers finished with zilpaterol hydrochloride. A randomized complete block design was used. British × Continental steers (n = 72; initial BW = 305 ± 13 kg) were blocked by BW and allotted randomly to 24 pens (8 pens per treatment; 3 pens per block; 3 steers per pen). Treatments were (1) control (CON); (2) YCW containing 100,000 IU of vitamin D2 per gram (5.0 g per steer per d; Y-D); (3) YCW C (5.0 g per steer per d; Y-C). Steers were supplemented 55 d, and zilpaterol hydrochloride was fed on d 30 to 49. Carcass data and strip loins were obtained. Strips were cut into steaks and assigned to 1 of 4 aging periods (7, 14, 21, or 28 d). Tenderness was examined using Warner-Bratzler shear force. Carcass-adjusted ADG from d 21 to 55 was 0.29 kg greater for Y-D and 0.35 kg greater for Y-C, when compared with CON (P = 0.04 and 0.01, respectively). Additionally, YCW increased G:F from d 21 to 55 by 28.46% for Y-C over CON (P = 0.01). Treatment Y-C displayed Warner-Bratzler shear force values 0.30 kg higher than CON and 0.29 kg greater than Y-D (P < 0.01). Within 7 d of aging, Y-C steaks were 0.62 kg (P = 0.005) and 0.54 kg (P = 0.014) less tender than CON or Y-D, respectively. For 14 d of aging steaks, Y-C Warner-Bratzler shear force values were 0.58 kg greater than CON (P = 0.008). These data indicate YCW supplementation could improve performance of finishing steers, and vitamin D2 supplementation at the current dosage did not improve tenderness.
- Yeast cell wall
- Zilpaterol hydrochloride