Magnesium (Mg)
The staggers mineral — and the reason a spring pasture can be short of it is usually potassium, not magnesium.
Often searched as grass staggers, hypomagnesaemia, grass tetany.
What it changes in the tools
- Grass staggers index
- K ÷ (Ca + Mg) in milliequivalents. Above 2.2 is the danger line; we open a watch band at 1.8, which is our own conservative buffer rather than a published cutoff.
- Source: Kemp & 't Hart (1957), the published tetany threshold.
Which feeds carry the most magnesium
From the cited composition of every feed in our library, as a percentage of dry matter. Useful when the answer is a feed change rather than a mineral product.
| Feed | % of dry matter |
|---|---|
| Sunflower meal | 0.53% |
| Canola meal | 0.46% |
| Maize gluten feed | 0.42% |
| Wheat bran (broll/pollard) | 0.42% |
| Molasses (cane) | 0.35% |
| Distillers grains (wheat) Wheat distillers grains run 34–40% protein depending on the process and any blending. Check the spec of what you’re actually buying. | 0.3% |
Mineral products, if you're dosing
Dosed in grams per head per day rather than fed by the kilogram — a different decision from changing the diet, so they are listed apart from the feeds.
| Feed | % of dry matter |
|---|---|
| Magnesium oxide | 55% |
| Dolomite | 12% |
| Magnesium chloride An anionic salt that doubles as a magnesium source; typically fed at 60–100 g/head/day pre-calving. | 12% |
Read it for your farm
Build the diet and it works the mineral balance out for you — including the indices below.
These are published reference bands, not a diagnosis. Mineral deficiencies and toxicities are diagnosed from the animal — blood, liver or tissue — not from a pasture test alone, and the treatment rates are veterinary decisions. Talk to your vet before dosing stock.