Growth performance, carcass characteristics, and fatty acid composition of Angus- and Wagyu-sired finishing cattle fed for a similar days on feed or body weight endpoint.

This study evaluated the feedlot performance, carcass characteristics, and fatty acid (FA) composition of Wagyu-sired and Angus-sired cattle at a similar days on feed (D) or body weight (B) endpoint. Wagyu-sired steers and heifers (WA) from two different sires, selected for either growth (G) or marbling (M), were compared with Angus-sired steers (AN, n = 13) in two independent incomplete-block design experiments at a similar days on feed (DOF; WA-GD, n = 9; WA-MD, n = 12) in experiment 1 or similar final body weight (BW; WA-GB, n = 9; WA-MB, n = 13) in experiment 2. Cattle were offered a corn silage-based growing diet for 119 d before being transitioned over 3 wk to a finishing diet. Data were analyzed as a randomized incomplete block design. In experiment 1, AN and WA-GD cattle had a greater (P < 0.01) off-test BW and average daily gain (ADGP < 0.04) than WA-MD cattle and AN had a greater dry matter intake (DMI; P < 0.02) than WA-GD and WA-MD cattle. The AN and WA-GD cattle had a greater carcass weight (P < 0.02) than WA-MD cattle. Percent kidney, pelvic, and heart fat (KPH) was greatest (P < 0.01) for WA-MD cattle, followed by WA-GD cattle, and lastly AN cattle. Total lipid (P < 0.03) and polyunsaturated FA (PUFA; P < 0.01) percentage were greater for WA-MD-cattle than AN and WA-GD cattle, as they tended (P = 0.11) to have the greatest 12th rib marbling score. In experiment 2, AN-cattle needed fewer (P < 0.01) DOF and had a greater (P ≤ 0.02) ADG, DMI, and gain:feed than WA-GB- and WA-MB-cattle. The WA-MB-cattle had a greater (P < 0.01) 12th and 6th rib marbling score, USDA quality grade, and 6th rib backfat thickness than AN-cattle. Compared with AN cattle, WA-GB cattle had a greater (P ≤ 0.01) percent KPH and lesser (P ≤ 0.03) rib thickness. The WA-MB-cattle had a greater (P ≤ 0.01) concentration of total lipid and PUFA than AN- and WA-GB-cattle, and lesser saturated FA (SFA; P < 0.01) concentration than AN-cattle in the longissimus muscle (LM). The 6th rib location of the LM had a greater (P ≤ 0.01) percentage of total lipid and SFA, but less (P < 0.03) MUFA compared with the 12th rib location. In conclusion, Wagyu-sired cattle selected for marbling potential had a lesser ADG, DMI, more marbling, more PUFA, and less SFA in the LM than Angus-sired cattle regardless of slaughter endpoint. Wagyu-sired cattle selected for growth potential had a similar ADG and carcass characteristics compared with Angus-sired cattle when fed for a similar number of days on feed.