Table 1.

Diet composition (as-fed basis)^a

Item	Phase
	1	2
Ingredient, %
Corn	48.47	57.30
Soybean meal	27.68	33.73
Dried whey	10.00	—
Fatb	5.00	5.00
Limestone	0.85	0.85
Monocalcium P (21.5% P)	1.60	1.70
Salt	0.30	0.35
l-Lys-HCl	0.33	0.33
l-Thr	0.15	0.16
Hydroxymethylthio-butanoic acidc	0.22	0.18
HP-300d	5.00	—
Vitamin premixe	0.15	0.15
Trace mineral premixf	0.25	0.25
Cu sourceg,h	—	—
Total	100.00	100.00
Calculated analysis
Standardized ileal digestible (SID) amino acids, %
Lys	1.30	1.25
Ile:Lys	63	62
Met:Lys	36	35
Met + Cys:Lys	58	58
Thr:Lys	65	65
Trp:Lys	18.4	18.4
Val:Lys	67	67
Net energy, kcal/kg	2,645	2,615
SID Lys:net energy, g/Mcal	4.91	4.78
Crude protein, %	21.7	21.3
Ca, %	0.85	0.80
P, %	0.78	0.75
Standard total tract digestible P, %	0.49	0.44

^a In experiment 1, phase 1 was fed from 6.0 to 9.8 kg and phase 2 was fed from 9.8 to 22.6 kg. In experiment 2, phase 1 was fed from 5.8 to 9.4 kg and phase 2 was fed from 9.4 to 21.6 kg. Dietary treatments were formed by adding 50, 100, or 150 mg/kg Cu (experiment 1) or 75, 150, or 225 mg/kg of Cu (experiment 2) from either tri-basic copper chloride or Cu-chelate at the expense of corn. The trace mineral premix was formulated to contribute 17 mg/kg of Cu to the complete diet for each experiment.

^b Choice white grease for groups 1, 3, and 4; beef tallow for group 2.

^c Alimet, Novus International.

^d HP-300, Hamlet Protein, Findlay, OH, formulated with 3.25% SID Lys.

^e Provided per kilogram of diet: 8,818 IU vitamin A, 2,205 IU vitamin D₃, 44.1 IU vitamin E, 0.04 mg vitamin B₁₂, 8.3 mg riboflavin, 82.7 mg niacin, 27.6 mg pantothenic acid, 4.4 mg menidione.

^f Provided per kilogram of diet: 17 mg Cu from copper sulfate, 0.3 mg I from Ca iodate, 110 mg Fe from ferrous sulfate, 33 mg Mg from manganese sulfate, 0.3 mg Se from sodium selenite, 110 mg Zn from zinc sulfate.

^g Copper-methionine hydroxy analogue (Mintrex Cu, Novus International).

^h Tri-basic copper chloride (IntelliBond C, Micronutrients, USA).