286 The Effect of Dietary Copper Levels and Source on the Performance and Profitability of Finishing Pigs

Abstract The micronutrient copper (Cu) is known to improve performance variables and the overall health of livestock animals. Different responses have been reported based on the molecular form of Cu and the inclusion level supplemented to growing pigs. The objective of this experiment was to evaluate four inclusion levels (25 ppm, 75 ppm, 125 ppm, 175 ppm) of CuSO4 and two Cu sources tribasic Cu chloride and organic Cu, in performance variables and economics of production of pigs during the grower-finisher phases. This trial was conducted at the Baynesfield Swine Research Unit at Baynsefield Estate in KwaZulu Natal, South Africa, following local farm protocols. A total of 528 animals (70 d of age; Initial BW of 33.1 ± 0.31 kg; TN 70 Topig Genetics) were randomly allotted to 48 mixed sex pens, with 11 pigs/pen. The treatments were as follow: TRT1 25 ppm CuSO4, TRT2 75 ppm CuSO4, TRT3 125 ppm CuSO4, TRT4 175 CuSO4, TRT5 hydroxy Cu, and TRT6 organic Cu. Each treatment had 8 repetitions with an equal number of boars and gilts (44). A four-phase corn and soy-based diet were formulated on the same specs having the premixes altered to accommodate the four Cu levels and/or Cu sources. Experimental animals had ad libitum access to feed and water. Feed intake and body weight were measured at every phase change. Additionally, the carcass variables (lean meat %, grading, cold carcass weight, and dressing%) were measured at slaughter. Feed cost, carcass value, MOFC, and cost per gain were calculated to determine economic value for each treatment. Statistical analysis was conducted in SAS (2021) utilizing the Proc GLM model for the average effects within each period, and if significant (P < 0.05) the Fisher’s test was used for LSMeans. There were no significant differences between the dietary treatments for BW, ADFI, ADG, FCR, or yield (Table 1). However, cost over feed was greater for the TRT6 fed pigs compared with either the TRT2 or TRT3 treatments but similar to the other treatments (P < 0.05). But when considering margin over feed, there were no significant differences amongst the treatments. In conclusion, this trial did not demonstrate an economic advantage of feeding copper greater than 75 ppm or utilizing alternative forms of copper.