Calcium Sources for Sheep: Feeds, Minerals and Milk Fever

The main calcium sources for sheep and goats are alfalfa (lucerne), other legume hays and browse leaves, plus mineral supplements such as ground limestone (calcium carbonate), dicalcium phosphate and species-specific mineral mixes. Barley, maize, wheat bran and most grains are poor in calcium, so grain-based rations need a clear calcium source and a good balance with phosphorus.

Calcium is easy to forget when you are focused on energy and protein, yet it drives bone growth, milk production and muscle function. Shortages usually show up at the worst moment: late pregnancy and early lactation, when a ewe or doe is under the most pressure. In fattening males, an imbalance between calcium and phosphorus is linked to urinary stones. This guide explains where calcium comes from, how to balance it, and when to call the vet.

Why sheep and goats need calcium

Calcium is the most abundant mineral in the body, and most of it is stored in the skeleton. Your animals need it for three big jobs:

• Bones and teeth. Lambs, kids and young stock need enough calcium to grow strong bones and sound legs.
• Milk. Milk is rich in calcium, so every litre a ewe or doe produces draws calcium out of her blood. Demand climbs sharply in early lactation, especially in dairy goats and ewes suckling twins.
• Late pregnancy. In roughly the last six weeks, the foetus builds most of its skeleton and pulls calcium from the mother. Ewes carrying twins or triplets need more.

Calcium also keeps nerves and muscles working, including the muscles of the uterus and rumen. That is why a sudden drop in blood calcium does not just weaken bones: it can put an animal on the ground within hours.

Practical calcium sources: feed and minerals

Forages

Alfalfa is the richest common feed for calcium, and legume leaves in general are good sources. Goats that browse shrubs and tree leaves often take in a fair amount of calcium from their browse. Grass hays such as Rhodes grass sit in the middle, while cereal straws are poor.

Grains and concentrates

Barley, maize, wheat, sorghum and millet are low in calcium and relatively high in phosphorus. Wheat bran and cottonseed meal are high in phosphorus and low in calcium. A fattening ration built mostly on barley and bran is therefore unbalanced unless it is corrected.

Mineral supplements

• Ground limestone (calcium carbonate): a cheap, concentrated source of calcium only, usually mixed into concentrate or a mineral premix.
• Dicalcium phosphate: supplies both calcium and phosphorus, useful when the ration is short of both, for example on dry, poor grazing.
• Mineral mixes and licks: choose a product labelled for sheep or for goats and read the calcium, phosphorus and copper levels. Sheep are very sensitive to copper; see our guide to minerals and salt licks for sheep and goats.

Do not add limestone or phosphate by guesswork. The right amount depends on the whole ration and should be worked out by a nutritionist or your vet.

These are qualitative guides only. Real values vary with variety, soil and storage, and a feed analysis is the only way to know your own figures.

The calcium-phosphorus balance and urinary stones

Calcium and phosphorus work as a pair, so it is not enough for both to be "present". The usual target in sheep and goat rations is more calcium than phosphorus, at roughly 1.5 to 2 parts calcium for every part of phosphorus.

The best-known risk is in fattening males on high-grain, low-roughage rations. Excess phosphorus, too little calcium and low water intake are well-known causes of urinary stones, which can block the urethra of ram lambs and bucks. Watch for a male that strains to urinate with little or nothing coming out, kicks at his belly or seems in pain. This is an emergency: call the vet straight away.

To reduce the risk:

1. Balance barley with alfalfa or a suitable calcium source, as shown in our barley and alfalfa ration guide.
2. Do not let grain become the whole diet; keep enough roughage in front of the animals.
3. Provide clean, cool water at all times, especially in hot weather.
4. Ask a nutritionist before any major change to a fattening mix.

Signs of low calcium around lambing (milk fever)

Low blood calcium, often called milk fever or hypocalcaemia, usually affects ewes in late pregnancy and goats around kidding or in early lactation. It is often triggered by sudden stress: transport, a feed change, a day without feed, handling or harsh weather.

Signs to watch for:

• Weakness and a stiff or wobbly walk.
• Muscle trembling.
• Going off feed and looking dull.
• Lying on the chest and unable to stand, sometimes with mild bloating.
• Rapid decline if nothing is done.

This is an emergency: call your vet urgently. Treatment must be given under veterinary guidance, so do not inject anything on your own. The signs can look like pregnancy toxaemia, and the vet will tell them apart. For prevention, see our guide to feeding pregnant and lactating ewes: steady feeding, good forage, the right minerals, and no sudden changes or stress in the last weeks.

How to manage calcium in practice

Managing calcium is less about a bag of limestone and more about knowing what each group eats and which ewes are close to lambing. A simple routine:

• Write down the ration of each group: how much alfalfa, how much barley, which mineral mix.
• Keep late-pregnant ewes, lactating ewes and fattening males in separate groups, since their needs differ.
• Read and keep the labels of concentrates and mineral products.
• Record any weakness or collapse near lambing, and any urinary trouble in males, to see if a pattern appears in one group.

In Throf you record meals for each group, and alfalfa, barley and minerals are deducted from your feed stock in kilograms, so you know what each pen actually ate. Ewes move through early pregnancy, late pregnancy and close-to-birth stages, which makes it easy to pull up the late-pregnancy group and watch it more closely. Illnesses and treatments are logged per animal, helping you and your vet spot a repeating problem.