Short answer
Yes, almost always. Forage (hay and pasture) is typically low in sodium, and most horses do not meet their sodium needs without added salt. A 500 kg (1,100 lb) horse at maintenance commonly requires around 30 grams (about 1 ounce) of salt per day, with needs increasing in heat, humidity, or during work.
Real-Life Example
It’s mid-summer and your horse is sweating during rides, but there isn’t much change in the salt block that’s in the paddock. Even though a block is available, some horses do not consume enough from a block alone to be adequate for their needs. Adding measured loose table salt to feed and offering free-choice loose salt, helps ensure intake matches demand, and helps avoid dehydration.
It Depends
Salt needs increase with:
• Heat and humidity - Horses lose more electrolytes through sweat in warmer conditions.
• Exercise and sweating - Work increases sweat loss, which raises sodium needs.
• Lactation - Nursing mares have higher fluid and electrolyte demands.
• Dry hay diets - Horses eating primarily hay often need additional salt to maintain proper hydration and electrolyte balance.
• Travel or stress - Both can increase fluid loss and alter hydration needs.
When to Seek Guidance
Consult your veterinarian if you notice:
• Reduced water intake
• Dry manure or signs of mild colic
• Unusual or exaggerated lethargy during heat
• Excessive sweating with slow recovery
Sources:
Lawrence L. (2022). The nutrient requirements of horses: historical perspectives.
Mad Barn – Equine Sodium & Salt Requirements
ECIR Group guidance - sodium intake in metabolic horses
