SHARING OPTIONS: The recent wet and cold weather over the last few days seems to have brought a spike in tetany and pneumonia cases. Speaking to a few farmers and vets this week, the recent wet and cold weather over the last few days seems to have brought a spike in tetany and pneumonia cases. Suckler cows have a poor capability of storing magnesium (Mg) in their body and need a daily supply to prevent deficiency. It is common with suckler cows when they are grazing very bare, as well as lush, pastures. This grass is frequently low in Mg due to quick growth and heavy slurry spreading, which is high in potassium and can have a negative effect on Mg uptake.