PSVI-30 Feedlot performance and carcass characteristics of beef steers under intensive management with or without an added nutritional packet

Abstract

Abstract The effects of a nutritional packet on performance and carcass characteristics of feedlot beef steers were evaluated. Thirty Angus-crossbred steers (BW = 542 ± 8.4 kg) were used in a randomized complete block design and allocated into pens with SmartFeed (C-Lock; 15 steers/treatment). Steers were consuming a steam-flaked corn-based finishing-diet, ad libitum, for the last 65-d on feed prior to slaughter, in which treatments were: 1) control and 2) a nutritional-packet [0.29% DM basis; live yeast (Saccharomyces cerevisiae; 8.7 Log CFU/g); Vitamin C (5.4 g/kg); Vitamin B1 (13.33 g/kg); NaCl (80 g/kg); KCl (80 g/kg)]. Individual BW was recorded every 14 d and carcass quality data was collected at slaughter. Steer was considered the experimental unit. The MIXED procedure of SAS was used with the fixed effect of treatment and the random effect of block. Total DMI was unaffected (P = 0.610) by treatment from d 0–65; however, control steers had greater (P = 0.030) DMI from d 54–65. The G:F was unaffected (P = 0.830) by treatment from d 0–35; however, it was greater (P ≤ 0.001) for steers fed the nutritional packet from d 0–50, and 0–65. Treatment did not affect (P = 0.920) ADG from d 0–35, however it increased (P ≤ 0.001) ADG from d 0–50 and tended (P = 0.060) to increase ADG from d 0–65. Carcass adjusted final BW tended (P = 0.060) to increase by 28% for treated cattle, whereas the Longissimus dorsi area tended to decrease (P = 0.090). No differences (P = 0.240) were observed for fat thickness, while yield-grade (P = 0.03) increased for treated cattle. The nutritional packet appears to improve performance in the final days of feeding steers under intensive management, and energy partitioning may be altered to fat deposition.