Copper Accumulation in Wisconsin Holsteins with Indications of Oxidative Liver Damage

An extensive review of Wisconsin Veterinary Diagnostic Laboratory(WVDL) accessions along with the results of slaughter house surveys indicate that copper is accumulating in the livers of Wisconsin Holsteins of all ages. Two hundred eleven WVDL accessions were reviewed based on breed(Holstein), age and results of inductively coupled plasma-mass spectroscopy(ICP-MS) liver element testing. The overall (all ages) mean liver copper(Cu) was 144ppm wet weight(ww). Animals > 2 years averaged 145ppm ww, those 1-24 months averaged 174ppm ww, those birth-30 days averaged 119ppm ww and fetuses averaged 95ppm ww. The average liver Cu for 45 fresh samples from cull dairy cows procured at a slaughter plant was 163ppm ww. This population may have included a few colored dairy cows (Jersey, Guernsey and Brown Swiss). Excess copper is thought to enter into reactions that result in the production of oxygen radicals, particularly the very toxic hydroxyl radical. These radicals damage the lipid moiety of cellular membranes, a form of oxidative stress. 4-hydroxynonenal (4-HNE) is one of many compounds that are generated by the reaction of oxygen radicals with the lipid moiety of cellular membranes. Immunohistochemical staining of livers with excess copper for 4-HNE is often positive, suggesting copper related oxidative damage. Copper is accumulating in the livers of Wisconsin Holsteins of all ages and may be causing oxidative liver damage.