Producers are being warned about problems like winter tetany which can develop in animals if their winter feed rations and minerals are off.

Catherine Lang is a Livestock and Feed Extension Specialist with the Ministry of Agriculture.

"So winter tetany is basically just the balance of the different minerals. So potassium, calcium and magnesium not being correct and it quite often happens in late pregnancy and after calving when those nutrient requirements of the cow or at that all-time high."

She says producers can prevent problems with winter tetany by getting feed tested and working with advisors on developing the proper mineral balance.

"So that can either be looking at levels of macrominerals and trace minerals without over supplementing or if you're dealing with antagonistic minerals such as sulphates in your water or molybdenum in your feeds. We can help pick proper trace minerals so that that binding doesn't happen."

She says if the mineral balance is off the animal can develop problems like winter tetany which if not treated can result in downer cows, convulsions or paralysis.