Part 2 of our in-depth 2 part series on Horse Supplements
The Importance of Horse Minerals in their Diet
In this article, we look at the importance of horse vitamins and minerals in their diet.
With one or two exceptions, your horse manufactures most of the vitamins required in their gut.
They will also get vitamins from green forages, and the sun (vitamin D).
For that reason, most good horse nutrition supplements focus on supplying minerals rather than vitamins that may be deficient in a horse’s diet.
Your primary consideration therefore when looking at horse supplements should be what supplements do horses need in terms of minerals?
Horse Nutrition
When it comes to nutrition, many minerals work synergistically with certain other minerals and vitamins. They also compete for uptake by the digestive system.
For this reason, minerals in these ‘relationships’ need to be present in certain ratios so the body can absorb and use (metabolise) them correctly
The relationship between calcium and phosphorus is one of the best-known examples of this.
Essentially, both these minerals need to be present in a diet in a certain ratio so the body can use them efficiently.
If this balance is significantly out of whack, the body will start absorbing the one in short supply from other sources i.e. from bones in this case.
Exactly What Horse Minerals Are Needed?
Sticking with calcium and phosphorus for the moment – for horses, the optimum ratio of calcium to phosphorus is around 2:1 respectively (6:1 is calculated to be the upper limit of tolerance for mature horses).
They will also do OK at ratios of 1:1 but if the ratio falls below this (0.75:1 for example), the body will begin grabbing calcium from bones to restore the balance.
The same happens in reverse – if calcium levels get too high, the body will start absorbing phosphorus from bones to compensate.

Important Horse Mineral Ratios For Your Horse’s Diets
There are a number of basic but important mineral ratios for horse diets.
When deciding which minerals your horse may be lacking, you’ll first need to know what, and how much, they’re already getting in their normal diet.
That may mean talking to an equine nutritionist or getting your horse’s diet professionally analysed. They may then suggest an appropriate commercial mineral supplement or will create one for you based on the results of the analysis.
Calcium (Ca) to Phosphorus (P) Ratio
Calcium and photophore are crucial for strong, healthy skeletal development, amongst other things. They also compete with each other for absorption in the gut. Maintaining the appropriate ratio between these 2 minerals is crucial. The ideal ratio is two parts Ca to one part P, with a range of 1:1 to 6:1 being acceptable.
Calcium (Ca) to Magnesium (Mg) Ratio
Calcium and magnesium work together to support correct nerve and muscle function, bone development, and overall metabolic balance. The ideal ratio for these 2 minerals is between 2:1 and 3:1 (Ca:Mg).
Calcium (Ca) to Sodium (Na) Ratio
Calcium, along with sodium, is also involved in maintaining cellular fluid balance, in nerve conductivity, and muscle function. Maintaining the correct ratio of between 2:1 to 3:1 (Ca:Na) is important for these functions.
Copper (Cu) to Zinc (Zn) Ratio
Copper and zinc are essential trace minerals involved in various physiological processes, including enzyme function, immune system support, and tissue integrity.
Zinc is also important for good hoof health, which is why good horse hoof feed supplements always contain zinc (and its related minerals). In fact, some hoof supplements make good all-round basic mineral supplements.
Copper is essential for triggering melanin (pigment) production, particularly red pigment. A deficiency of this mineral therefore can severely inhibit pigment production, resulting in dull faded coats (and orange chestnuts!).
The recommended ratio for Copper and Zinc is between 1:3 to 1:5 (Cu:Zn).
Iron (Fe) to Copper (Cu) Ratio
Iron is necessary for oxygen transport and energy production. Excessive iron levels can interfere with copper absorption and lead to imbalances. Notably, iron toxicity can cause a condition called haemochromatosis.
The optimal ratio for Iron and Copper is between 4:1 and 5:1 (Fe:Cu).
NB: Because Iron, Copper, Zinc, and another mineral Manganese all interact metabolically, they are usually grouped together in a single ratio which should ideally be between 4:1:3:3 – 5:1:5:5 respectively.
Sodium (Na) to Potassium (K) Ratio
Sodium and potassium are electrolytes. They are involved in fluid balance, nerve transmission, and muscle function. The ideal ratio for them is around 1:1 (Na:K).
Sodium (Na) to Chloride (Cl) Ratio
Sodium and chloride are also electrolytes and work together to maintain proper hydration, nerve function, and acid-base balance.
The recommended ratio is approximately 1:1 (Na:Cl). Sodium chloride is also known as common table salt!
Although most forage contains enough sodium and chloride, you should nevertheless always ensure your horse has access to (preferably) free choice salt licks. And clean water…
Why Horse Minerals are Needed?
Ensuring your horse receives essential minerals, in the correct ratios, is important for its overall health and wellbeing.
Horses that lack some of these minerals, or are getting too much of some at the expense of others, will eventually exhibit symptoms of these deficiencies.
Poor hoof health can be a sign of zinc deficiency.
Red or coppery tinges on the ends of black manes and tails can be indicative of an imbalance between Iron, Copper, and Zinc. Faded, dull, bleached, dry looking coats are often a classic indicator of copper deficiency.
Orange coloured chestnuts for example may be copper deficient. And so on…
While it may require some research and analysis, consulting with an equine nutritionist or other qualified professional can help identify any mineral deficiencies in your horse’s diet that need to be addressed.
By providing the necessary supplements and horse minerals, you can help support strong skeletal development, muscle and nerve function, and immune system health in your horse.