We all hear that salt plays a critical role in keeping horses healthy, happy, hydrated and performing at their best but how does this work for New Zealand horses?

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Whether you own a high-performance competition horse, have a pleasure horse for the occasional ride or “paddock potatoes” enjoying a cruisey life in the paddock, understanding your horse’s salt requirements is essential—through seasonal grass challenges, during warmer months when sweating increases and when unintended problems arise from hard feed and pasture changes.

Despite its importance, salt is often overlooked in equine nutrition. Many horse owners underestimate how much salt horses actually need, or assume a salt lick alone is enough. In reality, sodium deficiency can contribute create multiple health, behaviour and performance issues.
 

What Is Salt?

Salt is simply sodium chloride, one of the most important
minerals required by the body.

Salt should not be confused with Epsom salts, which is the form magnesium sulphate.

Sodium and chloride are classified as “macro minerals,” meaning they are required in relatively large amounts. They are also two of the body’s major electrolytes, alongside potassium, calcium and magnesium.

These electrolytes are dissolved in body fluids and carry electrical charges that are essential for normal bodily function.

Together, these minerals regulate hydration, nerve transmission, muscle function, blood pressure, circulation, skeletal integrity and many other critical processes within the horse’s body.

Horses, humans and other mammals cannot survive without salt.
 

Why Horses Need Salt

Unlike humans, horses generally consume diets higher in potassium and nitrogen and lower in sodium chloride and magnesium. This is due to seasonal influences on pasture such as drought-breaking rain, frosts or periods of rapid grass growth in spring.
Commonly fed plants such as clover and lucerne by nature can contain high levels of potassium and little to no salt.

While pasture potassium levels rise in the horses diet, sodium levels often do not increase to match. This imbalance can create many challenges for the health of horses.

Salt is essential for:

•          Maintaining hydration

•          Triggering the thirst response

•          Supporting nerve and muscle function

•          Transporting nutrients into cells

•          Removing waste products from cells

•          Maintaining healthy blood volume and pressure

•          Supporting stomach acid production and digestion

•          Assisting the body to process excess nitrates

 

Without enough sodium, the horse’s body struggles to function efficiently, even if the rest of the diet appears adequate.
 

Does Your Horse Drink Enough?

The Thirst Reflex - The what?

One of sodium’s most important roles is regulating hydration.  A major factor in hydration is the horses’s thirst reflex. This drives horses to drink - literally - life-giving water, not anything else luckily.
 
When sodium levels become too low, the horse’s thirst response is reduced.
This means the horse may not drink enough water, greatly increasing the risk of problems. Through the decades we have observed this - A Lot!

Dehydration can quickly affect:

•          Performance - fatigues easily

•          Recovery - seeming to be unfit.

•          Digestion - poor hydration can lead to colic or digestive issues.

•          Behaviour- becoming more anxious or spooky for example.

•          Temperature regulation - susceptibility to heat stress

 

Providing adequate salt helps replenish sodium losses and stimulates the horse to drink more water, restoring fluid balance more effectively.

 

 

 

Electrolytes in a bucket

When it comes to hydration of a horse, a common misconception is that horses need electrolytes as in those that come in a plastic bucket from the feed store. No they generally don’t. They just need sodium chloride and magnesium. Electrolyte supplements can be part of the problem - adding in unwanted and problematic levels of potassium, some sodium and chloride,  but not enough magnesium. It’s important to read labels when buying electrolyte products and if unsure add salt and good quality magnesium.

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Salt as a foundational addition to feed is very safe and together with quality magnesium can make an amazing difference. 

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Where does salt go?

Horses lose salt every day through urine and manure—even while resting in the paddock. A horse at maintenance can lose approximately 20 grams of salt daily, with losses increasing significantly through kidneys efforts to excrete excess potassium, sweating during hot weather, exercise or stress.

This slippery slope of low sodium chloride with rocketing potassium is very common and adds to the problems faced by a “grass affected horse”.

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We advise that it is best to avoid rather than fix this situation which can take much longer.

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Signs Your Horse May Need More Salt

Horses have a strong natural instinct to seek sodium when deficient. Common signs of inadequate salt intake include:

•          Licking people, fences, trees or stable walls

•          Chewing wood excessively

•          Poor hydration

•          Reduced performance

•          Lethargy

•          Muscle issues

•          Excessive sweating

•          Poor coat or body condition

•          “Spooky or erratic” behaviour

•          Lowered feed utilisation

•          Horse refusing to drink when they should be thirsty - after hard work for example.
 

This can create a downward cycle of issues unnecessarily when salt is a very inexpensive and readily available mineral.  
 

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How Much Salt Does a Horse Need?

A practical guideline is to feed a minimum of 10 grams of salt per 100 kilograms of body weight each day.

For example:

•          A 500 kg horse requires approximately 50 grams of salt daily

•          This equals roughly two heaped tablespoons

This seems a lot, but decades of experience has shown us the huge advantages for our horses health and performance when these guidelines are followed.

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It’s also a common misconception that horses may get hardened arteries but this would only happen if horses were on hundreds of grams of salt daily. 

Horses in hard work, hot climates or heavy sweat conditions or suffer with Anhidrosis (reduced ability to sweat) will require additional salt.
 

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Salt Blocks or Licks

Some horse owners rely solely on salt licks, but problem is horses rarely consume enough salt this way to meet their actual daily requirements.
Some horses become bored with licking, while others develop sore tongues. Some just don’t like salt and need “training” to eat salt in their meals. It is also difficult to monitor exactly how much they are consuming if a salt lick is the sole supply. Complications of this system means to monitor intake salt licks would need to be weighed daily, where multiple horses live together horses, and rain washing away salt from blocks. 

The most reliable method is to mix measured salt directly into the horse’s daily feed. Horses unfamiliar with salt may need a gradual introduction, but most adapt quickly.

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Training horses to happily consume salt is particularly valuable for horses that travel or compete, as it helps maintain hydration away from home.

 

 

The Pasture Problem

Modern pasture conditions can contribute significantly to sodium deficiency. Fast-growing grasses often contain excessive potassium and nitrogen, while remaining naturally low in sodium.

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Under high nitrate conditions—such as after fertiliser use, frosts or rapid pasture growth—the body requires adequate sodium to safely excrete excess nitrates. If sodium levels are insufficient, the horse may instead draw on calcium and magnesium reserves, depleting these reserves, further contributing to mineral imbalances.

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Horses grazing lush pasture can still display signs of mineral deficiency or ill-thrift despite abundant feed availability.

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Iodised or Plain Salt?

The choice between iodised and plain salt depends largely on the horse’s overall diet.

If your horse is already receiving a well-balanced vitamin and mineral supplement containing iodine, additional iodised salt is usually unnecessary. However, horses not receiving supplemental iodine may benefit from iodised salt to support thyroid function although iodine levels may not be sufficient for correct supplementation.

 

The Importance of Clean Water

Because adequate salt intake encourages horses to drink more, access to fresh, clean water is essential at all times.

Water troughs should be cleaned regularly, particularly during hot weather when algae and bacteria multiply quickly. Plastic troughs can heat up significantly in the sun, causing water quality to deteriorate and discouraging horses from drinking.

Clean, cool water and proper salt intake work hand in hand to support hydration and overall wellbeing.

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A Foundation of Equine Health

Salt is not simply an optional supplement—it is a fundamental requirement for life. Sodium and chloride influence nearly every major system within the horse’s body, from hydration and digestion to muscle contraction and nerve function.

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While many owners focus heavily on vitamins, supplements and specialised feeds, ensuring adequate daily salt intake is often one of the simplest and most effective ways to support horse health, behaviour and performance.

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Whether your horse is competing, breeding, working or simply enjoying retirement, proper salt intake forms a vital foundation for long-term wellbeing.

 

Please contact us if you have any questions