Table 3.

Effects of trace mineral injection and vitamin E supplementation on carcass characteristics of feedlot heifers¹

Item	Treatment2					P-value
	Cont + Sal	Cont + MM	Vit E + Sal	Vit E + MM	SEM	Diet	Injection	Diet × Injection
Ending live wt, kg	538	543	536	544	10	0.98	0.51	0.91
HCW, kg	340	340	338	341	6	0.99	0.83	0.79
Carcass yield %	63.2	62.5	63.0	62.7	0.4	0.95	0.19	0.65
REA, cm2	82.8	84.0	82.0	84.6	2.1	0.97	0.35	0.72
12th-rib fat, cm	1.2	1.3	1.3	1.3	0.1	0.65	0.96	0.49
KPH, %	2.2	2.1	2.2	2.3	0.1	0.09	0.31	0.81
Calculated yield grade	3.1	3.1	3.2	3.0	0.1	0.85	0.56	0.62
Marbling score3	480	500	565	550	35	0.08	0.89	0.54
Extractible lipid, %	7.1	7.7	8.5	8.7	0.8	0.18	0.58	0.75

¹Trace mineral injection included 15 mg/mL of Cu, 10 mg/mL of Mn, 5 mg/mL of Se, and 60 mg/mL of Zn.

²Heifers were supplemented with no additional vitamin E in the diet (Cont) or 1,000 IU of vitamin E·heifer⁻¹·d⁻¹ (Vit E) for 89 d prior to slaughter. Heifers received saline (Sal) or trace mineral injection (TM) at a dosage of 1 mL/68 kg BW at day 1 of the 89-d feeding period.

³Marbling scores: 400 = Small⁰⁰ (low choice) and 500 = Modest⁰⁰ (average choice).