Commercial dog foods generally contain more copper than a dog with copper storage disease can handle. (dogcare.dailypuppy.com)
It should be noted that dogs with copper storage disease should not be given Vitamin C because it may increase the damage to the liver. (dog-health-guide.org)
These breeds are prone to a form of liver disease called copper storage disease in which too much copper accumulates in the liver and causes problems with liver function. (dog-health-guide.org)