The perfect grass tetany storm is brewing on spring-calving suckler farms. We’ve had an exceptionally varied few days weather-wise, with temperatures plummeting; add in the rain and we get the first tetany stressor – weather.

In many cases, cows and calves will be in fields close to the yard – likely the go-to fields for slurry. These often have a high potassium concentration in their grass. Ingesting big amounts of potassium can tie up magnesium in the rumen – the second tetany stressor.

On early-calving farms, bulling activity should be getting going too. Bulling cows won’t eat and can wear themselves out – the third tetany stressor.

For me, these are the big three that could affect suckler farmers this week, along with the obvious unavoidable one of a calf to rear!

A suckler cow needs 30g to 40g of magnesium daily. There are a number of ways that we can get this into her (see table). For me, meal supplementation will be most effective at this point and should be considered at least for a few weeks.

We are killing two birds with one stone by getting the magnesium in and infusing the diet with energy. Don’t forget how important it is to prevent too much body condition loss between calving and breeding.