Performance and carcass traits of early-weaned steers receiving either a pasture growing period or a finishing diet at weaning

A 2-yr study was conducted to evaluate 1) steers fed ad libitum high concen trate after weaning (CONC), or 2) steers grown on pasture for 82 d, followe d by high-concentrate finishing (PAST), on the performance and carcass trai ts of 74 early-weaned (117 d of age) steers. Potential breed differences we re evaluated using crossbred steers of three types: 1) 3/4 Angus x 1/4 Simm ental (BRI), 2) 3/4 Simmental x 1/4 Angus (CON), and 3) 1/2 Wagyu x 1/4 Ang us x 1/4 Simmental (WAG). Steers were randomly assigned within breed to the two treatments. There was no interactions (P > .10), so the data were pool ed over years. The CONC steers had an ADG that was .17 kg/d higher(P = .000 1), intake 1.09 kg/d lower (P = .0001), and gain:feed ratio .013 unit bette r (.190 vs .177, P = .008) than PAST steers overall. Growing treatment did not affect total concentrate consumed (P = .97). The BRI steers required 31 d less than did CON steers (P = .008), and 23 d less than WAG steers (P = .05) when fed to a constant fat end point (1.1 cm). The BRI steers exhibite d an ADG .16 kg/d higher (P = .0003), tended (P = .07) to have an ADG intak e .49 kg/d higher, and exhibited gain:feed .01 unit better (.189 vs 180) th an WAG steers. When compared with CON steers, BRI steers consumed 310 kg le ss total concentrate(P = .0003). No differences(P > .38) were observed betw een growing treatments for carcass characteristics or sensory attributes ex cept that CONC steers tended (P = .11) to improve percentage of steers grad ing Average Choice or higher by 47% over PAST steers. The WAG steers had 76 -unit higher marbling score (1,000 = Small(00), 1,100 = Modest(00)) (P = .0 06) than BRI steers, resulting in 19% more (P = .09) steers grading greater than or equal to Choice and 82% more (P = .03) grading greater than or equ al to Average Choice. Liver (P = .15) and rumen (P = .01) weights as a perc entage of hot carcass weight were reduced for CONC steers. The CONC steers had higher gain, lower intake, better efficiency, reduced liver and rumen w eights, and consumed the same amount of total concentrate when compared wit h PAST steers. The BRI steers had less finishing days and lower daily intak e compared with CON steers. The WAG steers had more days finishing, lower g ain, lower intake, more undesirable efficiencies, consumed the same amount of total concentrate, and improved quality grades compared with BRI steers.