Abstract The effects of a nutritional packet fed to beef steers during the final 64 d of the feedlot finishing phase on growth performance and carcass characteristics were evaluated. Crossbred-Angus steers (n = 120; initial BW = 544 ± 52 kg) were assigned to 30 pens (4 steers/pen; 15 pens/treatment) in a randomized complete block design where pen represented the experimental unit. A steam-flaked corn-based finishing diet was fed ad libitum, and treatments were applied as follows: 1) control and 2) 30 g/steer-daily (DM-basis) of the nutritional packet (containing live yeast [8.7 Log CFU of Saccharomyces cerevisiae], vitamin C [5.4 g/kg of Ascorbic acid], vitamin B1 [13.33 g/kg of Thiamine hydrochloride], sodium chloride [80 g/kg] and potassium chloride [80 g/kg]). The nutritional packet used ground corn as a carrier and was included at 1 % of diet DM. Orts were quantified daily (if any) and subtracted from the total dietary DM offered to calculate DM intake. Unshrunk BW were collected on d 0, 21, 42 and 64 before daily feeding at 0630 h. Data were analyzed using the GLIMMIX procedure of SAS. Average daily gain (P = 0.89), dry matter intake (P = 0.57) and, gain:feed (P = 0.66) were not affected by the inclusion of the nutritional packet. The 12th rib fat deposition was increased (P ≤ 0.02) for cattle fed the nutritional packet compared with control (15.70 vs. 13.36 mm, respectively). Consequently, calculated yield grade was also increased (P ≤ 0.03) for cattle consuming the nutritional packet (3.32 vs. 3.02). An improved carcass fat-deposition without any deleterious effects on growth performance potentially warrant less days on feed when cattle receive such nutritional packet.