Copper poisoning of sheep after ad libitum supplementation of rations by a mineral feed

Within 8 weeks 22 of 400 sheep died with symptoms of Cu intoxication. In the liver of 2 dead sheep Cu contents of 491 and 830 mg/kg dry matter were found. The concentration of copper in the concentrate and other feedstuffs (grass, hay, straw, kale, dried sugar beet pulp) could not explain the development of Cu-toxicosis. The mineral-vitamin-supplement contained 86.7 mg Cu/kg. Obviously the Cu intoxication of previously Cu loaded sheep was provoked by offering the mineral supplement ad libitum (with intervals of 3-4 days), the intake of this mixture reached values up to 400 g/animal and day. By renunciation of mineral supplements in the same flock 7 months later lambs died due to Cu deficiency (Cu content in the liver: 13-14 mg/kg dry matter).