PS6-16. Effects of Copper Feeding Strategy on Growth Performance of Nursery Pigs

Abstract A total of 2,204 pigs (PIC 337 × 1050, initially 5.3 ± 0.09 kg) were used in a 38-d study to determine the effect of Cu feeding strategy on the growth performance of nursery pigs. Pigs were randomly allotted to pens with 29 pigs per pen. Pens of pigs were blocked by initial weight and allotted to one of four treatments in a randomized complete block design with 19 pens per treatment across two rooms. Four Cu feeding strategies consisting of increased levels of Cu in different nursery phases were evaluated. Pigs were fed in 3 dietary phases, phase 1 (d 0 to 10), phase 2 (10 to 24), and phase 3 (d 24 to 38). Feeding strategy 1 served as the control with no pharmacological levels of Cu. Strategy 2 included pharmacological Cu levels in only phase 3. Strategy 3 consisted of pharmacological Cu in phases 2 and 3, and strategy 4 included pharmacological Cu in all three phases. Within each experimental phase, there were two diets provided, either a base level of Cu (17 mg/kg) provided from CuSO4 in the vitamin/trace mineral premix, or pharmacological levels (167 mg/kg) of Cu by adding 150 mg/kg Cu from tribasic copper chloride (SAM Nutrition, Bloomington, MN) in addition to the base level. All diets contained pharmacological levels of ZnO (3,000 mg/kg Zn in phase 1 and 2,000 mg/kg Zn in phase 2). Pigs were weighed and feed disappearance was measured to determine ADG, ADFI, and G:F. From d 0 to 10 (phase 1), there was no evidence of difference in performance between pigs fed the base level of Cu and pigs fed a diet containing 167 mg/kg added Cu. From d 10 to 24 (phase 2), pigs fed added Cu had a greater ADG (P = 0.012) and ADFI (P = 0.021) compared to pigs fed the base level of Cu, with no evidence of a difference for G:F. Pigs fed added Cu for phases 1 and 2 had a greater ADG than pigs fed the control with no pharmacological levels of Cu (P = 0.047). During phase 3, there were no differences in performance among treatments; however, pigs fed pharmacological Cu in phases 2 and 3 had numerically greater ADG compared with other feeding strategies. There were no differences in overall growth performance or removals and mortality. These data suggest that when pharmacological levels of Zn are used, nursery growth performance can be improved by the addition of pharmacological levels of Cu in the phase 2 diet; however, the improvement did not affect overall ADG, ADFI, G:F, removals or mortality.