Copper sulphate is added routinely in some countries to grower rations as a growth promoter at levels between 50-175ppm. Levels above 250ppm may interfere with normal growth rate particularly if the levels of zinc and iron in the ration are low. If the levels of zinc and iron are normal a level of 500ppm becomes toxic. Plants such as subterranean clover may also produce a mineral imbalance in outdoor pigs by increasing the retention of copper.

Clinical signs

These are usually gradual in onset unless there has been a massive intake of copper. In acute poisoning there is severe gastro-enteritis, abdominal pain, diarrhoea and jaundice, an enlarged liver and blood in the urine. In less acute cases there is anaemia and reduced growth rate.

Diagnosis

This is based on history, clinical signs and post-mortem findings. Laboratory tests for copper levels of more than 250ppm in the liver and 60ppm in the kidney confirm the diagnosis.

Treatment

• The response to treatment is poor.
• Calcium versonate by injection can be of help.
• Seek veterinary advice.