Q: I live in the southern U.S., where it gets extremely hot during summer. I’ve been adding a tablespoon of plain salt to my horses’ feed once per day. My three horses drink nearly 100 gallons of water daily—though some days it’s less. When adding salt to my horse’s feed, is it better to use iodized or plain salt? Do I need to buy salt from a feed store, or is grocery store salt acceptable for horses? How much salt should I add per feeding?

A: Horses should always have free-choice access to salt (sodium chloride), along with added salt in their daily concentrate ration to meet their sodium requirements. An average 500-kilogram (1,100-pound) horse at maintenance needs about 2 U.S. tablespoons of salt daily to meet baseline sodium needs. That requirement increases with exercise and in hot weather and can vary based on body weight and sweat loss.

The amount of salt required increases as both sodium and chloride, along with other minerals such as potassium, magnesium and calcium, are lost in sweat. When a horse is sweating, electrolytes should be supplemented in addition to their daily salt intake.

Sodium and chloride are electrolytes as they are minerals that carry an electrical charge when dissolved in fluid. However, electrolyte supplements differ from regular salt because they are designed to replace what is lost in sweat. A quality performance electrolyte will contain sodium, chloride, potassium, magnesium, and calcium. Equine nutritionists recommend adding electrolytes to replenish what your horse is losing in their sweat.

When choosing salt for your horse, you have several options: blocks, licks, loose table salt, sea salt, and Himalayan salt. Salt blocks or licks offer convenient free-choice access, but horses often don’t consume enough of these forms to meet their needs. Adding loose salt directly to their feed helps prevent sodium deficiency.

When selecting loose salt for meals, equine nutritionists generally recommend iodized salt—the added iodine helps balance the horse’s overall ration. You can purchase this salt at the feed or grocery store. If your horse prefers the taste of sea salt or Himalayan salt, those serve as acceptable substitutes for iodized salt. However, if you are not feeding iodized salt, it is recommended to check the guaranteed analysis on your horse’s concentrate to ensure iodine is listed.

However, if your horse receives a kelp-based supplement, avoid iodized salt. Kelp typically provides more than enough iodine on its own.

Keep in mind that mineralized salts—the brown blocks or loose salt containing trace minerals—do not provide minerals in high enough amounts to meaningfully impact your horse’s nutrition requirements. Therefore, they can be offered as a salt source but should not be relied on to meet your horse’s trace mineral requirements.

Take-Home Message

For horses at maintenance, feed a minimum of 2 U.S. tablespoons of loose salt daily in the feed ration alongside a free-choice salt source. In hot climates or when working, horses’ salt requirements increase. The exact amount depends on factors such as body weight, workload, and sweat loss. In general, if it’s hot enough for your horse to sweat, you should also provide supplemental electrolytes in addition to their daily salt.

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