Ark Veterinary Centre

Copper Poisoning in Sheep

Jan 5, 2020

SRUC's Ayr Disease Surveillance Centre has seen an increase in cases of Copper poisoning recently. Copper poisoning can be acute; caused by overdose of Copper containing products, or chronic in nature.     

Chronic copper poisoning is the more common presentation and is due to ingestion of excess copper in the diet over a long period of time. Sources of copper may include concentrates, mineral licks and in some cases background levels of Copper in forage, coupled with low levels of antagonism in susceptible white faced sheep breeds. Mineral licks formulated for cattle often contain higher levels of copper which can be harmful to sheep if inadvertent access is gained. Once the liver storage capacity is exceeded, or if there is associated liver disease or hypoxia, Copper can be released into the blood stream where it causes haemolysis (destruction of blood cells). It is worth noting that a haemolytic crisis can be precipitated by stress such as travelling and sales and current exposure to copper does not have to feature. 
Presenting signs have ranged from sudden death to lethargy and recumbency followed by death. The mucous membranes, sclera and conjunctiva will often be jaundiced. At post mortem, the liver will be bronzed and kidneys black with evidence of haematuria. If carcasses are autolysed jaundice may not be a notable feature. Copper poisoning should be suspected and investigated in cases of unexplained death in both adult sheep and lambs in intensive systems. Fresh liver and kidney are required for analysis.