Table 2.

Effects of zinc¹ supplementation on performance parameters of non-steroidal implanted and steroidal implanted² beef feedlot steers

	NoIMP				TE200				Contrasts3
	Zn0	Zn30	Zn100	Zn150	Zn0	Zn30	Zn100	Zn150	SEM	L-NoIMP	Q-NoIMP	L- TE200	Q- TE200	NoIMP vs. TE200
Steer (n)4	17	15	16	16	15	16	16	16
BW, kg
day 0	490	495	491	492	495	492	492	489	7.6	0.99	0.91	0.67	0.95	0.98
day 18	528	532	532	531	531	534	534	540	1.8	0.34	0.18	0.002	0.34	0.005
day 59	595	596	603	596	605	607	608	603	3.8	0.50	0.17	0.81	0.26	0.002
days 0 to 18
ADG, kg	2.01	2.24	2.22	2.18	2.17	2.31	2.32	2.65	0.101	0.34	0.18	0.002	0.34	0.005
DMI, kg	11.4	11.2	11.2	12.1	11.5	11.4	11.7	12.0	0.24	0.11	0.09	0.09	0.48	0.52
G:F	0.177	0.192	0.200	0.181	0.188	0.203	0.199	0.222	0.0094	0.71	0.05	0.02	0.61	0.01
Carcass-adjusted overall5
Final BW	594	593	600	593	604	606	610	613	4.0	0.81	0.35	0.10	0.99	<0.0001
ADG	1.70	1.69	1.79	1.68	1.87	1.89	1.96	2.01	0.066	0.81	0.35	0.10	0.99	<0.0001
G:F	0.151	0.152	0.163	0.145	0.162	0.168	0.170	0.174	0.0053	0.74	0.04	0.12	0.86	<0.0001

¹Cattle were supplemented 0, 30, 100, or 150 mg Zn/kg DM (Zn0, Zn30, Zn100, or Zn150, respectively) from ZnSO₄.

²Steroidal implant strategies included no steroidal implant (NoIMP) or a Component TE-200 (TE200; 200 mg trenbolone acetate + 20 mg estradiol; Elanco Animal Health, Greenfield, IN) on day 0.

³Contrast statements were formed to test for linear (L) and quadratic (Q) effects of Zn supplementation within non-steroidal implanted (L-NoIMP and Q-NoIMP) or steroidal implanted (L-TE200 or Q-TE200) steers. A separate contrast statement was formed to test for differences between non-steroidal implanted steers and all steroidal implanted steers (NoIMP vs. TE200).

⁴Initial body weight (BW) was utilized as a covariate in all performance analyses including body weight (BW), average daily gain (ADG), dry matter intake (DMI), and gain:feed (G:F).

⁵Carcass adjusted performance was calculated using the average dressing percentage for all treatments: 62.25%.