As our autumn herds approach drying off, and the cows head into their final stages of pregnancy, it’s important to ensure they have sufficient copper and selenium on board. 
 
Copper is important for general health, milk production, fertility and calf viability. In late pregnancy, the calf creates a large copper demand on the pregnant cow. In addition, zinc supplementation for facial eczema can interfere with copper uptake at this time. 
 
Doing liver biopsies is the only way to determine the copper status of your cows and calculate whether supplementation is necessary. These tests are quick and easy to perform and made as painless as possible for the cows. Around 6 – 8 samples per mob are needed. 
 
Selenium is the other important trace element to consider. It improves animal health through the calving period and helps the cows return to cycling. Supplementation is highly variable farm to farm and is dependent on soil levels, fertiliser use, amongst other factors. The only way to be sure about the selenium status on your farm is to take some blood samples – just 4 – 5 per mob is adequate. 
 
And let’s not forget about our heifers coming home from grazing. Their trace element profiles can be very different to the cows at home, and it’s important that we check their copper and selenium levels too. 
 
Finally, a quick note about magnesium. Typically, magnesium levels aren’t a problem during the autumn dry period due to the higher levels in the pasture at this time of year. But this mineral still plays a major part in transition feeding, from 4 weeks pre-calving through the calving period. Speak to your vet about the right transition mix for your autumn herd.

Happy dry-off to all you Autumn calvers, and remember, being proactive about trace element testing now will set you up well for calving.