When we think of salt for horses, we are talking about sodium chloride, which is the same as table salt. All horses need sodium chloride, and so there are amounts of these nutrients in most of the feeds your horse is getting already from pasture, hay, grain and supplements. However, the question is how much salt should your horse be getting each day and do you need to supplement? The answer is your horses probably need to be on a salt supplement and may need a large amount if sweating excessively. Equine sweat contains a lot of sodium and chloride so the more your horse sweats, the more sodium the horse needs in the ration. Sodium is also the electrolyte that stimulates thirst so if your horse is low in sodium, water consumption may decrease and then lots of problems can occur, including colic.
It is believed most average size adult horses need about 50 grams of salt per day. But as I mentioned earlier, it is hard to put an actual number on it when you consider a sweating horse needs more. Regardless, a study was performed on moderately exercised warmbloods on a low forage diet that had 100 grams salt added to their diets daily, which caused acidification of the blood and increased sodium chloride in the urine. Adding 50 grams salt per day did not have any of these side effects so the authors felt adding 50 grams salt per day to a normal horse’s ration was a reasonable amount: it’s about 3 ounces of table salt per day. You can use an electrolyte supplement instead but sometimes it is difficult to determine the amount of salt in the product so you should be safe adding 3 ounces of table salt to your horse’s ration daily year round.