Suckler farmers should be keeping on top of magnesium supplementation to combat the risk of grass tetany in cows suckling calves.
Heavy, frequent rain showers are reducing the dry matter of grazing swards and where lactating cows are grazing on wet, lush grass, the risk of tetany is greatly increased.
Cows cannot store magnesium, so supplementation is essential. Options for supplementing magnesium are varied. Most preferred options usually come down to cost and being practical to use.
If using lick buckets, go with one bucket per 10 cows, although not all animals will use them. Adding magnesium to water will have limited benefits in wet conditions as cows will tend to drink less.
Keep lactating cows off paddocks that received potash (K) via slurry and chemical fertiliser in the past two to three weeks to reduce the risk of tetany.
Potash will lock up magnesium in soils, limiting the amount taken up by cows via grazed grass.