Two trials were conducted to determine the effects of added copper from copper sulfate or copper chloride on performance of growing-finishing pigs. A total of 2,277 pigs with an initial weight of 71.6 lb were used in a commercial research facility in southwest Minnesota. Adding copper to the diet improved performance during the first
two weeks in the finishing barn regardless
of copper source or level. The results of
these experiments indicate that low levels
of copper chloride or copper sulfate (50 to
100 ppm) can be an effective and economical growth promoter when fed for the first two weeks to growing-finishing pigs.