Effect of Copper in Swine Diets on Fresh Waste Composition and Anaerobic Decomposition2

An experiment was conducted to determine the effect of copper sulfate in swine diets on fresh waste composition and on decomposition of the waste stored in anaerobic pits. Vitamin and mineral fortified corn-soybean meal diets with 0, 125 and 250 ppm copper were fed to growing-finishing pigs (18 to 91 kg) in spring and summer trials with daily fresh waste collection and addition to anaerobic pits.Copper concentrations (wet basis) in the anaerobic pits from pigs fed the 0, 125 and 250 ppm copper diets for trial I were 3.15, 34.27 and 44.63 ppm, respectively. For trial II, copper concentrations were 3.55 and 48.61 ppm, respectively, for diets containing 0 and 250 ppm copper. Average elemental copper excretion for the 250 ppm copper diets ranged from 433 to 490 mg per head per day.The presence of copper sulfate in swine diets did not affect fresh waste composition. Copper sulfate decreased the decomposition of the waste in anaerobic pits as shown by the greater reduction of dry matter and volatile solids in waste from pigs fed no copper sulfate. Dry matter content was reduced 65% in anaerobically stored waste from pigs fed 0 ppm copper, while the dry matter content was reduced only 55 and 51% from pigs fed the 125 ppm and 250 ppm copper diets in trial I. In trial II the dry matter was reduced 41% for the 0 ppm stored waste and 31% for the 250 ppm stored waste.