Chronic oversupply with copper as a potential herd health problem on a German dairy farm Diagnostic value of different sample types for assessment of copper supply in dairy cows

In contrast to sheep, chronic copper oversupply or toxicity represent infrequent events in cattle. This case report describes a chronically elevated exposure to copper arising from excessive supplementation of mineral feedstuff leading to a herd health problem in a German Holstein dairy herd. For diagnosis on herd level, 10 cows of both the close-up (VB) and high-yielding (HL) groups were selected and blood as well as urine samples were collected. Clinical chemistry investigation of these samples only revealed slightly raised activities of liver enzymes in cows of the HL group. Analysis of the total mixed ration (TMR) of both groups revealed a significant oversupply with copper, zinc, cobalt, and selenium. On the basis of these findings, the copper content of urine, feces, pigmented hair as well as plasma ceruloplasmin activity were measured additionally. Liver biopsies were performed in cows of the HL group and in heifers, the latter of which had received a mineral feed for young cattle according to the manufacturer's instructions. Results indicated increased fecal copper in both HL and VB groups as well as above normal or high-normal values of hepatic copper and cobalt resp. selenium, zinc, and manganese in the HL cows. In contrast, heifers had physiological amounts of trace elements in their liver tissues. This report demonstrates the suitability of fecal analysis and TMR for a reliable assessment of copper supply, while blood, urine, and hair failed to represent appropriate sample types. In order to attain a dependable diagnosis of potential copper oversupply, a liver biopsy-which may also be performed in buiatric practice - is deemed necessary.

Automated summary

This case report describes a chronically elevated exposure to copper in a German Holstein dairy herd, caused by excessive supplementation of mineral feedstuff. The study confirmed the issue of copper oversupply through various diagnostic methods including blood and urine sample analysis, total mixed ration testing, and liver biopsies. The findings suggest that fecal analysis and total mixed ration testing are reliable for assessing copper supply, while liver biopsy is deemed necessary for a dependable diagnosis of potential copper oversupply.