A combination of chromium propionate and yeast supplement (CrY; TruMax, Varied Industries Corp., Mason City, IA) was added to diets of crossbred steers (n = 504; 402 ± 5.8 kg initial BW) to evaluate the effect on feedlot performance and carcass quality. Steers were selected on the basis of initial plasma glucose concentrations ≤6.0 mM, stratified by initial BW, blocked into heavy (H; 420 kg BW) and light (L; 384 kg BW) groups, and assigned to treatments of 0 (CON) or 3.3 g/d CrY (provided 0.5 mg Cr/kg diet DM) with 6 pens/diet within each block. Body weights were measured at 21-d intervals. Finished cattle were weighed and transported to a commercial abattoir where severity of liver abscesses and HCW were collected at harvest, and yield and quality grades, LM area, and 12th rib subcutaneous fat thickness were determined after 36 h of refrigeration. There were no CrY × time × weight block interactions for ADG, DMI, and G:F (P = 0.36; P = 0.49; P = 0.41, respectively), and no CrY × block interactions for ADG and DMI (P = 0.06; P = 0.75, respectively), but a CrY × block interaction (P = 0.03) was observed for G:F; CON-L had poorer efficiency compared with other groups. Yield grade and marbling score tended to be less (P > 0.07) for CrY compared with CON, but other carcass measurements were unaffected by treatment (P > 0.30). Chromium propionate in combination with yeast may improve feed efficiency of lighter cattle, but other effects were minimal. Table 1. Feedlot performance and carcass traits of steers

Item	CON-L	CrY-L	CON-H	CrY-L	SEM
DMI, kg/d	12.57	12.29	13.00	12.83	0.17
ADG, kg/d	1.70	1.76	1.88	1.84	0.03
G:F1,3	0.1349	0.1430	0.1445	0.1434	0.0023
HCW, kg	398	400	408	407	3.65
LM area, cm2	88.13	90.06	93.10	92.97	0.96
12th rib fat, cm	1.30	1.22	1.27	1.24	0.43
Yield grade2,3	2.79	2.53	2.66	2.66	0.07
Marbling score3,4	459	453	430	414	6.54

¹CrY × weight block interaction (P = 0.03). ²CrY × weight block interaction (P = 0.08). ³Effect of CrY (P ≤ 0.08). ⁴Marbling score determined by camera imaging; Small = 400 to 499.