Effects of Increasing Copper from Tri-Basic Copper Chloride or a Cu-Amino Acid Complex on Growth Performance of Nursery Pigs

Many U.S. swine nutritionists supplement swine diets with added Cu to promote growth of weanling pigs. However, there is little research comparing different organic and hydroxyl Cu sources for their growth promoting benefits. Thus, the objective of this study was to compare the effects of increasing added Cu from Tri-basic CuCl (TBCC, IntelliBond-C; Micronutrients, Indianapolis, IN) or Cu-AA (Mintrex-Cu; Novus, St. Charles, MO) on growth performance of nursery pigs. A total of 665 pigs [Group 1; 350 barrows (DNA 200×400; initially 6.4 kg)] and [Group 2; 315 barrows and gilts (DNA 241×600; initially 5.2 kg)] were used. There were 5 pigs/pen and 10 replications/treatment in group 1 and 5 pigs/pen and 9 replications/treatment in group 2. Pens of pigs were allotted by BW to 1 of 7 dietary treatments arranged as a 2×3 factorial plus a control diet, with main effects of Cu source (TBCC or Cu-AA) and level (75, 150, or 225 ppm). Data were analyzed as a randomized complete block design using PROC GLIMMIX (SAS Institute, Inc.) with pen as the experimental unit and dietary treatment as the fixed effect. Random effects of group and block within group were included in the model. All diets, including the control, contained a trace mineral premix formulated to contribute 17 ppm of Cu from CuSO₄ in the complete diet. Experimental diets were fed in two phases from d 0 to 14 and d 14 to 35. Overall, there were no Cu source × level interactions observed. Increasing Cu increased ADG (linear, P=0.048) and final BW (linear, P=0.019) with no effect on ADFI. This resulted in a tendency for improved G:F (linear, P=0.052) with increasing dietary Cu. In summary, Cu source did not affect growth performance and because the growth benefits were linear, it is unknown from our study if increasing added Cu beyond 225 ppm would further improve growth.

		Added Cu, ppm							Probability, P<
	Control	TBCC			Cu-AA				Cu level
Item1	0	75	150	225	75	150	225	SEM	Linear
BW, kg
d 0	5.8	5.8	5.8	5.8	5.8	5.8	5.8	0.60	0.974
d 35	21.1	21.0	21.7	22.0	21.6	22.2	21.8	2.77	0.019
d 0 to 35
ADG, g	436	430	452	459	441	459	451	66.4	0.048
ADFI, g	637	629	651	660	647	654	637	83.7	0.305
G:F	0.681	0.683	0.692	0.694	0.677	0.700	0.701	0.0168	0.052
1No effect of copper source P>0.315.