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Evaluation of copper source addition in the grow-finish phase
A total of 1,167 pigs (66.36 ± 4.10 kg) were used to evaluate differences in 3 copper sources added in the late grow-finish phase. Treatment diets included a control (CON) with no added copper, and the CON diet plus 150 ppm of CuCl2 , CON plus 150 ppm of CuSO4 , or CON plus 80 ppm of organic copper (Cu Mintrex®, Novus International, Inc., St. Charles, MO). Diet phase changes occurred at d 21 and 32 days post-allotment. Pigs were penned in blocks of either 24 or 25 pigs/pen with a computerized feed system delivering feed to single-sided feeders. There were a total of 12 replications per treatment group. Data were analyzed as a randomized complete block design using the PROC MIXED procedure of SAS with pen as the experimental unit and treatment as a fixed effect. From d 0 to 21 of the study, there were no significant differences (P > 0.24) in performance for the overall effect of CON-fed pigs compared to those fed supplemental copper, regardless of source. During the second phase, there was a tendency for increased ADG (0.84, 0.88, 0.89, and 0.89 kg/d; P = 0.06, respectively) among pigs that were fed supplemental copper, regardless of source or inclusion rate. The inclusion of supplemental copper significantly improved (0.31, 0.34, 0.35, 0.33; P < 0.01, respectively) the G:F, regardless of source or dose. At d 32, all pigs were weighed and first markets occurred. At this point, all pigs were fed a common diet that included ractopamine and all pens remained on study until completely marketed (approximately 35 days after the first market date). There were no differences (0.98, 0.98, 0.98, 0.97; P > 0.27) in the growth performance of pigs during the ractopamine phase. For the overall period (d 0 to market), copper supplementation improved G:F (0.33, 0.34, 0.35, 0.34; P = 0.01, respectively). When organic copper was fed, the response was not significantly different from the CON, but did tend (P = 0.10) to have improved G:F. There also tended to be a decrease in overall ADFI compared to the CON when either CuSO4 or CuCl2 was fed (2.67, 2.46, 2.56 kg/d; P= 0.13, respectively). In conclusion, the addition of supplemental copper, regardless of source, resulted in improved G:F in late finishing swine diets.
Keywords: copper, grow-finish, pigs