Table 4.

Effects of zinc¹ supplementation within non-steroidal implanted and steroidal implanted² beef steers on trace mineral and plasma urea nitrogen concentrations

	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)	10	9	9	9	8	9	9	9
Plasma Zn4, mg/L
day −1	1.22	1.31	1.32	1.32	1.28	1.28	1.37	1.35	0.053	0.17	0.41	0.16	0.67	0.42
day 18	1.31	1.34	1.43	1.44	1.25	1.21	1.33	1.39	0.037	0.003	0.53	0.001	0.36	0.001
day 40	1.33	1.25	1.36	1.42	1.29	1.27	1.35	1.38	0.038	0.01	0.12	0.03	0.82	0.49
day 55 liver5, mg/kg DM
Zn	115	113	122	115	118	118	125	127	6.1	0.69	0.59	0.20	0.97	0.20
Mn	8.7	7.9	8.6	8.6	8.2	7.9	7.6	8.4	0.46	0.65	0.55	0.82	0.15	0.10
Cu	310	274	277	252	278	268	268	293	29.9	0.15	0.86	0.67	0.49	0.94
Fe	181	181	173	184	178	170	171	184	11.2	0.99	0.47	0.59	0.28	0.59

¹Zinc was supplemented to cattle at 0, 30, 100, or 150 mg Zn/kg DM from ZnSO₄ (Zn0, Zn30, Zn100, or Zn150, respectively).

²Steroidal implant strategies included no steroidal implant (NoIMP) or a Component TE-200 (TE-200; 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).

⁴Plasma Zn from day −1 was utilized as a covariate in days 18 and 40 plasma Zn analysis.

⁵Liver samples were collected on days 55/56 with half of the samples collected on each d.