If they’re unavailable at critical times like calving, the risk of issues such as retained membranes, metritis and mastitis can increase. Supporting cows with adequate trace elements helps keep them healthy, cycling and in the herd.
“Inside a cow’s body are billions of tiny cells working hard every day. Trace elements act like maintenance crew - protecting those cells, keeping energy flowing, and helping the immune system do its job,” Farm Source Programme Manager (On-Farm Performance) Tenielle Ellingham says.
Trace element levels can change
Even when tests show sufficient levels, cows can dip into short periods of insufficiency. Changes in feed composition, reduced absorption (such as soil ingestion), and dilution in spring pasture can all impact availability. At the same time, demand increases with stress, lactation, calf growth and immune challenges.
Double demands around calving
During pregnancy, cows are maintaining themselves, growing a calf and preparing for the transition into lactation. Trace elements like selenium, copper, zinc and iodine are critical.
Periods of stress can further increase demand, while feed intake may drop - creating a mismatch at a critical time.
Don’t forget your heifers
Heifers face additional pressure, as they are growing their own frames while supporting a pregnancy. This makes them a higher-risk group, so testing and supplementation ahead of their return as R2s is important.
Take a targeted approach
Testing helps remove the guesswork and ensures supplementation is appropriate. It also helps manage the risk of excess where multiple sources are used, such as palm kernel or copper supplements.
- Diagnostic testing: Liver biopsy remains the most reliable way to assess copper status.
- Targeted delivery: Once you have the data, choose the right supplementation method.
- System check: Diets high in fodder beet or maize silage can dilute trace element intake and may require a more robust plan.
- Timing matters: Testing in autumn may not reflect levels at calving, when demand is highest and levels can drop.
So, what should you do?
Test, and supplement where needed. Consider top-ups during high-demand periods like pre-mating and pre-calving, when even cows previously assessed as sufficient can benefit. Injectable options can help by bypassing absorption challenges and restoring liver reserves more directly.
The bottom line
Cows with the trace elements they need at the right time are more resilient, productive and profitable. Addressing trace element status now can help prevent disease and support a smoother calving period.
Talk to your vet or local TSR about your herd’s trace element status and put a plan in place ahead of calving.
