Interactive lesson

Minerals and salt, step by step

Interactive lesson: salt, calcium, copper, selenium and magnesium for every species on the holding, the lick and its holder, and the signs that call for the vet.

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The whole lesson as text

1. Salt for herbivores

Every animal needs salt, and herbivores get too little of it from grass and hay.

Lick always available — Salt and a mineral mix for that species always available to ruminants, horses and rabbits, under cover.
How much a day — Roughly: goat and sheep 5–15 g, cow 30–60 g, horse 25–50 g, more in summer and when working.
Pigs and poultry — Salt only in the feed: hens 0.3 %, pigs 0.3–0.5 %. Never salty food, and always plenty of water.
Iodised salt — Feed salt and licks usually contain iodine already; it says so on the label.

Why: That's why ruminants, horses and rabbits seek out salt and lick it. Pigs and poultry get salt only through their feed, because salty food can poison them.

A sign salt is short: they lick sweat, urine and wood, and their appetite is poor.
Iodised salt is good for all species, especially where goitre was once common, such as Derbyshire in England or the Great Lakes “goitre belt” in North America.

2. Calcium for hens

An eggshell is almost pure calcium carbonate, so a layer needs a lot of it.

Layers: 3.5–4 % — That's how much calcium layers' feed needs. An eggshell is almost pure calcium.
A separate dish — Give limestone grit or crushed oyster shell in a separate dish, next to the feed.
Eggshells to the compost — Don't give eggshells back to the hens: they go to the compost. That way the hens don't learn to peck eggs either.
Chicks kept apart — Chicks and pullets need 0.9–1 % calcium. Never give them layers' feed or limestone.

Why: A layer gets calcium from her feed and from limestone or oyster shell in a separate dish. In a young hen too much calcium damages the kidneys, so chicks never eat layers' feed.

Buy calcium as feed limestone, coarser limestone grit or crushed oyster shell.
Thin or soft eggshells can mean a shortage of calcium or vitamin D.