Abstract
Three feeding trials involving 264 crossbred pigs were conducted to study the effects of copper sulfate (250 ppm Cu), copper oxide (250 ppm Cu), and chlortetracycline (50 mg./lb.) on performance of pigs. In the first experiment each of the additives improved rate of gain and feed efficiency when fed to 200 lb. or when fed to 125 lb. and withdrawn thereafter, with the exception of the copper sulfate fed to 200 lb. Copper levels in the livers of pigs fed supplemental copper were higher than pigs fed the control ration. There was significantly less iron in the liver of pigs fed copper sulfate as compared to those fed supplemental copper oxide. In the second trial the effect of zinc and iron on the response to copper was studied. Pigs receiving the copper supplemented rations gained significantly faster than the pigs receiving no added copper. When the diet was not supplemented with zinc there was no response to copper supplementation. Hemoglobin levels were lowered in the presence of added copper and in the absence of supplemental iron. In the third experiment pigs receiving added copper gained significantly faster than the controls. Heat and water treatment of the diets did not significantly affect the response to copper. Copyright © 1963. American Society of Animal Science . Copyright 1963 by American Society of Animal Science