Minerals
The bands, and where they come from
What a pasture or diet figure should be, for the minerals that actually cause trouble on New Zealand farms — each with the published source it came from, and what it changes in the free tools.
Where the evidence doesn't support a band, these pages say so instead of inventing one. NZ authorities decline a confident herbage cutoff for iodine and zinc, so those pages give the cited context and no verdict.
Trace elements
Read off a herbage or blood test against a band. Copper, cobalt and selenium are the three classic NZ deficiencies; molybdenum is the antagonist that causes the fourth.
Copper (Cu)
The trace element where the right rate for one species can kill another — and the one most often locked up by something else in the pasture rather than absent from it.
Selenium (Se)
One of the three classic New Zealand pasture deficiencies — and one where the national median sits not far above the deficiency cutoff, with a seasonal dip on top of that.
Cobalt (Co)
A rumen-microbe requirement rather than an animal one — the microbes use it to make vitamin B12 — which is why young growing stock feel it first.
Molybdenum (Mo)
Not a deficiency to fix but an antagonist to watch: high pasture molybdenum ties up copper the animal has already eaten, so a copper figure that looks adequate stops being adequate.
Zinc (Zn)
New Zealand's zinc question is almost never a deficiency — it is the facial-eczema dose, and what a long dosing programme does to copper.
Iodine (I)
The element where the herbage number tells you least: what matters is whether a pregnant dam is eating brassica, because the goitrogens in it block iodine uptake regardless of how much is there.
Macro minerals
Read off the diet as a balance rather than a level — the ratios behind grass staggers, milk fever and the sulphur watch.
Calcium (Ca)
The macro mineral that decides two different problems: bone in growing stock, and whether a springing cow can mobilise fast enough at calving.
Phosphorus (P)
Rarely short on New Zealand pasture, and the half of the calcium ratio that quietly goes wrong on grain.
Magnesium (Mg)
The staggers mineral — and the reason a spring pasture can be short of it is usually potassium, not magnesium.
Potassium (K)
Almost never deficient here, and the usual cause of the two mineral problems that look like something else — staggers and a stubbornly positive DCAD.
Sodium (Na)
Cheap to fix and easy to over-diagnose: the widely quoted pasture ratio is an agronomy signal, not a diagnosis.
Sulphur (S)
A nutrient at normal levels and a neurological hazard well above them — and the co-factor that turns adequate copper into deficient copper.
Read your own numbers
The animal health tool takes a herbage test and reads the trace elements against these bands for your stock class. The feed calculator does the macro-mineral balance from the diet you actually feed.
These are published reference bands, not a diagnosis. Mineral deficiencies and toxicities are diagnosed from the animal, not from a pasture test alone, and the treatment rates are veterinary decisions. Talk to your vet before dosing stock.