sheep AFBI warns about the risk of chronic copper poisoning in sheep by Dr Siobhan Corry Disease, Surveillance & Investigation Branch AFBI Veterinary Sciences Division
AFBI would like to make flock owners aware of the risks of chronic copper poisoning. This condition can be seen throughout the year but circumstances in autumn such as prolonged concentrate feeding of ewes in lactation, concentrate feeding to rams and lambs for sale, coupled with stress associated with sales and the changeable weather are risk factors for the disease. 60
While copper is an essential part of enzymes governing many biological functions, sheep are particularly susceptible to the toxic effects of excess copper. Toxicity is most frequently observed in the Charollais, Texel and Suffolk breeds, and less frequently observed in the mountain breeds. Clinical disease follows a period of excess intake and occurs when
the liver’s capacity to store excess copper is exceeded and there is a sudden release of copper by the liver into the circulatory system. This typically occurs after weeks or months of accumulation of copper and often coincides with a period of stress on the animal. The sudden release of copper by the liver causes haemolysis and irreversible damage to the kidney
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and the brain. Copper poisoning is slow to develop but sudden in onset. The eyes and skin become jaundiced and post mortem examination reveals an orange liver, black kidneys and red/brown urine. Biochemistry results show a toxic level of copper in the liver and the kidney. Serum copper levels do not provide a reliable warning of imminent toxicity.
