Perrin D J, Schiefer H B, Blakley B R
Can Vet J. 1990 Sep;31(9):629-32.
The addition of excessive copper to a commercially prepared dairy ration caused chronic copper toxicity in a dairy herd. A formulation error by a feed company resulted in copper levels of 800 to 1,000 mg/kg in the "as fed concentrate," amounting to about 400-500 mg copper/kg of the whole ration. Five animals died with typical signs of acute copper toxicity, including intravascular hemolysis and methemoglobinemia. A further 39 cows died on the farm from a combination of debilitation and secondary infectious causes, and 215 were sent to slaughter because of debilitation and poor milk production. The mortality of calves born to dams that had been fed the toxic concentrate was approximately 50%.We postulate that dairy cows, particularly pregnant cows, may be more susceptible to copper toxicity than other cattle, and suggest reexamination of the presently allowable maximum levels of copper supplementation of diets for dairy cattle.
在商业制备的奶牛日粮中添加过量铜导致奶牛群发生慢性铜中毒。一家饲料公司的配方错误导致“风干精料”中的铜含量达到800至1000毫克/千克，相当于整个日粮中约400 - 500毫克铜/千克。5头动物死于急性铜中毒的典型症状，包括血管内溶血和高铁血红蛋白血症。另有39头奶牛因虚弱和继发感染原因在农场死亡，215头因虚弱和产奶量低被送去屠宰。食用了有毒精料的母牛所产犊牛的死亡率约为50%。我们推测，奶牛，尤其是怀孕母牛，可能比其他牛对铜中毒更敏感，并建议重新审视目前奶牛日粮中铜补充剂的允许最高水平。
