Overexposure to copper is hepatotoxic and nephrotoxic to cattle and can result in high mortality in herds. Copper poisoning can occur in acute or chronic form, which differ in their presentation of clinical signs.
Chronic copper poisoning is damaging to the liver and kidneys, and eventually leads to liver or kidney failure. It occurs when the amount of copper absorbed in the cow's diet exceeds the nutritional requirement and the cow's capacity to excrete the additional levels. Copper levels accumulate in the cow's liver over a period of time and upon reaching saturation they rupture and distribute high levels of copper into the bloodstream. Chronic cases can be caused by imbalances of other minerals (i.e low dietary intake of molybdenum results in an increased uptake of copper by the cow's gastrointestinal system, leading to copper poisoning. This can occur even with normal levels of copper when levels of molybdenum have decreased). Chronic consumption of copper often results in unspecific clinical signs which can often make the diagnosis challenging.