Magnesium is vital to the every-day health of ruminants and cannot be stored in the body. Low levels can lead to rapid death in the case of hypomagnesemia or milk fever and reduced levels can lead to lack of thrive and reduced yield due to decreased metabolic activity.
There are a number of things that affect magnesium uptake
• Dry matter intake (can be affected by a number of things)
• Potassium(too high)
• Sodium (too little)
• Ammonia or nitrogen high
• Not enough fibre
• CLA fats in spring grass can affect magnesium uptake
Magnesium also plays a vital role in calcium metabolism.
We must remember also it is estimated cows only ingest/absorb 20% of magnesium (average) so we must look at ensuring supplementation at risk period is optimal.
We often call this deficiency grass tetany as it occurs at grass. It can occur at other times where intakes are affected. This can be weather related or in stressful conditions like weaning time for suckler cows.