What is Copper Storage Disease in Dogs?

Copper Storage Disease (CSD) or Copper Storage Hepatopathy in dogs is a disease that more of us are becoming aware of — we’ve certainly had plenty of emails about it from concerned dog parents. 

So here’s everything you need to know. 

What is Copper Storage Disease?

Copper is an essential mineral. It is supplied through the diet and is handled in the liver. Excess copper is dealt with in healthy dogs through the excretion of copper through bile. 

CSD occurs when copper is stored in the liver, causing liver damage, and scarring and leading to liver disease which can be fatal. CSD can occur from a recessive gene (COMMD1) which affects copper metabolism, but this isn’t always the case. 

What dog breeds get Copper Storage Disease?

Several breeds are more often affected by CSD, including Bedlington Terriers, Labradors, Skye Terriers, West Highland Terriers, Dalmatians, and Doberman Pinschers. Within these breeds, there are characteristics too. For instance, in Doberman Pinschers it is almost always females who are affected. 

It was previously thought that CSD only occurred in breeds which were affected by the inherited COMMD1 gene, but CSD has the potential to occur in any breed of dog and at any age. 

What are the symptoms of Copper Storage Disease in dogs?

For many dogs, CSD is found during adulthood, but it is possible for copper to begin accumulating from around 5 months of age, with excess copper being seen in the liver from 12 months old. 

CSD can go undetected for many years until the late stages of the disease when symptoms such as anaemia, weight loss, lethargy, vomiting, and depression can be noticed. Dogs with the COMMD1 recessive gene often accumulate levels of copper which are toxic to the liver by 2 to 4 years of age. 

Diagnosis and Treatment of Copper Storage Disease

CSD is diagnosed through a vet conducting a liver biopsy. Often CSD is managed through a low copper diet and often a copper chelation medication such as Penicillamine. The goal is to reduce copper absorption and encourage its excretion from the body. Copper chelation medication binds copper and stops so much being absorbed into the body by encouraging more to be excreted in urine. 

Zinc supplementation can also be used to reduce copper absorption from the diet. Zinc blocks copper absorption from the digestive tract. Regular blood tests are carried out of pets with CSD to monitor liver health and the success of the treatment over time.

How can dogs develop Copper Storage Disease? 

AAFCO sets the nutritional guidelines for pet foods, to ensure that pet food contains all the nutrients needed, in the correct balance for our pets to be healthy. For copper, there is no upper nutritional limit for AAFCO nutritional profiles. It is thought that this can cause an oversupply of copper in pet food which leads to the potential for copper to accumulate. 

Copper is often present in vitamin and mineral premixes which are added to foods to ensure that they contain adequate nutrition to meet the AAFCO Nutritional profiles. Pet foods often now contain more meat, or animal and fish proteins than traditionally. 

This means more minerals, including copper, are provided to the pet food through these ingredients. When combined with potential added copper via a premix means that copper far in excess of the nutritional requirement can be delivered in pet food. 

The maximum value for copper was removed due to a lack of evidence to support the value. The previous maximum was also based upon data in pigs which it was decided was not a good representation of dogs and cats. 

What is being done about Copper Storage Disease in dogs?

Re-introducing a nutritional maximum for copper is something that is being proposed to AAFCO for future versions of the nutritional guidelines, and to safeguard against toxicity issues. 

Testing for COMMD1 genetic predisposition to CSD is carried out now, especially in breeds such as the Bedlington Terrier, where it was thought that up to 50% of dogs in the USA and UK carried the recessive gene. 

This means that breeders can avoid matching dogs who both carry the recessive gene and avoid this impaired copper metabolism in their puppies.

What can I do to protect my dog from Copper Storage Disease? 

If you’d like to know the quantity of copper in your pet’s food, you can ask the manufacturer who will be able to advise. The quantity of added copper and source is declared in the FEDIAF guidelines of Europe, but the quantity is not always given under AAFCO. 

Either way, the manufacturer can advise the total quantity of copper in a diet. The AAFCO nutritional profile states a requirement for 7.3mg of copper per kg on a dry matter basis for maintenance, and 12.4mg/kg for growth. You can compare the copper in your pet’s food to these values. 

Other sources of copper in our pet’s diets are eggs, beans and legumes, some cereals, liver, and organ meats. If your pet is recommended a low copper diet, be sure to avoid dehydrated liver and organ, and treats containing these ingredients too.