Table 2.

Day 56 BW and days 0 to 56 ADG of nonimplanted or implanted beef steers fed varying concentrations* of supplemental trace minerals

Performance	No IMP			IMP†			SEM‡	P value
	CON, n = 12	REC, n = 11	IND, n = 12	CON, n = 12	REC, n = 12	IND, n = 12		GS	TM	GS × TM
BW, kg
Day 56	473z	468z	478z	494y	513x	509x	5.48	<0.01	0.17	0.10
ADG, kg/d
Days 0–56	1.50c	1.45c	1.61c	1.88b	2.18a	2.18a	0.070	<0.01	0.01	0.05

^a,b,cWithin rows, means without a common superscript differ (P ≤ 0.05).

^x,y,zWithin rows, means without a common superscript tend to differ (P ≤ 0.10).

^*Supplemental trace mineral treatments: CON (no additional supplemental trace minerals), REC (2016 NASEM recommendations: 10 Cu, 30 Zn, 20 Mn, 0.10 Se, 0.15 Co, and 0.50 I; mg/kg), and IND (feedlot consultant recommendations from Samuelson et al. (2016): 20 Cu, 100 Zn, 50 Mn, 0.30 Se, 0.20 Co, and 0.50 I; mg/kg). Sources of trace mineral included copper sulfate, zinc sulfate, manganese sulfate, calcium iodate, sodium selenite, and cobalt carbonate.

^†Growth-stimulated implanted steers (IMP) received Component TE-IS (16 mg estradiol + 80 mg TBA) on day 0 and were reimplanted with Component TE-200 (20 mg estradiol + 200 mg TBA) on day 56, whereas NoIMP received no implants.

^‡Reported SEM is greatest of all treatments because of uneven number per treatment.

SEM, standard error of the mean.