Copper Toxicity
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Hepatotoxicity
- sheep are very susceptible
- they have poor ability to excrete copper in the bile
- copper accumulates in hepatocytes until it reaches a critical level
- the hepatocytes die and release the copper into the blood
- causes haemolysis of the red blood cells
- this haemolysis further damages the hepatocytes
- releases even more copper
Predisposing factors
- contamination of foodstuffs and pasture with copper
- any damage to the biliary system as in ragwort poisoning
- pastures low in molybdenum
- increases the availability of dietary copper
- molybdenum combines with copper to form insoluble complexes in the gut
Gross
- carcass
- jaundiced
- reddish
- liver
- swollen
- soft
- orange in colour
- kidneys
- deep red
- red urine due to haemoglobinuria
Microscopically
- periacinar hepatic necrosis and profuse bile due to haemolysis and cholestasis
- copper can be demonstrated with special stain - rhodanine
Genetic inheritance
- Bedlington and West Highland White Terriers
- copper toxicosis susceptibility
- inherited as autosomal defect
- copper levels can be very high in the livers of these animals
- there is no haemolytic crisis
Clinical
- ill thrift
- progressive neurological signs due to liver failure
Gross
- liver is small and fibrosed
- jaundice is not a consistent feature