Are you Risking Copper Toxicity??

Unsure about what supplements your herd needs this winter and going into calving? Concerned you might be wasting time and money on over-supplementation, and even risking toxicity? It might be time to get some clear answers, so you can make confident and cost-effective decisions.

Traditionally, winter has been a high-risk time for trace element deficiencies in cattle, particularly copper and selenium. However, in modern New Zealand farming systems, the concern has shifted, especially when it comes to copper. The widespread use of palm kernel (PK), which contains high levels of copper, has made over-supplementation a much more common issue.

Following a prolonged summer drought, many farms have relied heavily on PK as a feed source. As a result, cows may have accumulated substantial copper stores in their livers. In these cases, further supplementation through winter could pose a serious risk of copper toxicity.

Selenium, on the other hand, remains a key trace element for supporting growth and immune function. It's especially important in the lead-up to calving, a time when cows are naturally immunosuppressed.

If you’re unsure about your herd’s mineral status- or you want to avoid the risks and costs of unnecessary supplementation- we strongly recommend getting some testing done. The most accurate way to assess copper and selenium levels is via liver sampling. This can be through liver biopsies from animals on-farm. Please contact the clinic if you would like any further advice about supplementation and/or testing.