EN
The experiments were performed on 72 Black-and-White bulls 18 months old and an average body weight of 345,9 kg. Protein and energy were covered at a required level but copper supply was 4,7 mg/kg of dry matter. The animals were divide into three groups. Group I (control) without any treatment, group II — animals treated with one capsule of Copporal, group III — animals treated with two capsules of Copporal for 3 months. Body weight was maesure before and at the end of the experiment. The level of copper and the activity of superoxide dismutase were determined in blood and in livers of slaughtered bulls. It was found that in animals fed one capsule of Copporal mean daily weight gains incresaed by 52,7%, while after two capsules by 61,8%. Also the activity of superoxide dismutase increased significantly both in blood and livers to 141,5 g/mg and 155,5 g/mg, respectively.