Calcium + Phosphorus
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HHIO doesn't include Calcium or Phosphorus in its formulations, as on average an adult horse will get what they require from forage and bucket feeds. Calcium in particular can be provided in excessive amounts (forage, lucerne) and Phosphorus in low amounts. We don't include, as not all horses need the top up of Calcium and/or Phosphorus. Those that do, can be simply and affordably supplement with a product called DCP - Dicalcium Phosphate which is easily sourced from your local farm or feed store. You can supplement this more economically than us adding it into the formulas, increasing the dose rate and therefore cost.
The ratio that they are consumed in the diet is also important. We utilise the base feed to address this ratio.
IF you are following the HHIO feed protocol the base calcium and phosphorus needs will typically be met within the inclusions in your hard feed. On the odd occassion and depending on your particular forage make up and especially active growing grass in spring, you may need to supplement if your horse starts seeking extra by eating dirt, stripping bark off trees etc.
Calcium
For example, lucerne chaff (we love the balanced use of lucerne) is high in Calcium and is the most highly absorbable form of calcium for horses to consume.
Phosphorus
Copra, rice bran and linseed (crushed or flax flake/pellets) are all higher in phosphorus. Which fed together will provide Ca:P.
Sourcing DCP:
We no longer offer DCP for purchase but you can source 20kg bags from your local farm store (Farmsource, Farmlands, PGG Wrighstons) which is the most economical option especially for larger numbers. For one horse the Feed Central product may work better.
Typical analysis of DCP is: 10 grams: 2.2g calcium / 1.8g phosphorus
Dose Rate 20 - 100g depending on needs & size of animal
A 25ml scoop = 20g
Testing of your forage is the accurate way to know what intake your horses need. However as a general minimum base guide we suggest 20g dose daily for Broodmares in foal, and weaned young stock up to around 5 years of age. For Last trimester and lactating Broodmares suggest 40g-60g dose rate. Based on a 500kg weight.
Stockists:
Feed Central - This is Harvest grains DCP product
DancaPhos - Nutritech product which also includes Vitamin A & D, which is safe to use alongside HHIO products.
Posted: Tuesday 12 May 2026
