Salt is the only mineral essentially absent from everything your horse eats, including grass. Because of this, horses have a natural taste for salt, and it’s the only mineral they will actually seek out and voluntarily consume in plain form.
If the horse’s intake of salt is too low to meet his minimal requirements, his body will adjust by holding less water. This keeps the concentration of salt in his body fluids at a normal level. That’s good. What’s not good is that this leaves the horse in a dehydrated state.
He’s dehydrated because, while the salt concentration in the body fluid is normal, his total body fluid is below normal. Plus, his natural instinct to drink won’t work because his brain isn’t getting a ”low sodium” signal. The only way to break this cycle is to make sure a normal amount of salt gets into the horse for a few days, as this will change the salt concentration in the body fluids and encourage the horse to consume adequate amounts of water.
Note: If the horse is otherwise healthy and just loafing around, this dehydration state may not cause problems. But, if the horse has further losses of salt and water through sweating or diarrhea, severe dehydration and overheating can occur.
Secondary potassium deficiencies often also happen, because the kidney will excrete more potassium than normal so that it can hold onto sodium. This can cause problems like muscular cramping, thumps and poor intestinal motility. Salt-deficient horses also drink less, predisposing them to impaction and other forms of colic from the decreased water consumption.
Preferred Form Of Salt
There are a lot of pricey salts on the market, from this mine, that lake or whatever ocean bed, with a lot of hype about how much better they are because they contain a host of other minerals (albeit in tiny amounts). Don’t be taken in (see March 2008). Horses didn’t evolve consuming salt deposits from the depths of a mine or the bed of the ocean. The fact is, all those other minerals in the salts are contaminants. Few of them serve any purpose at all in the horse’s body, and some are actually toxic. Plain, white salt is what your horse needs and is best for him.
Salt bricks or pasture-size blocks are convenient and fine to use as long as you make sure the horse consumes as much salt from them as he needs. As a rule of thumb, the horse should eat a pound (16 ounces) of salt every 16 days in cool weather and up to twice that amount in hot weather.
Many horses simply won’t put enough time into licking the block to get enough. Breaking the block into pieces that the horse can easily pick up and bite might help. You can also use bagged salt in chunk size or use table salt added to meals and/or put out loose in feeders. Two tablespoons of table salt weighs 1 oz., and there are three teaspoons in a tablespoon.
How to Supplement
To determine if you need to be directly supplementing salt, you first need to know how much your horse is taking in. Check supplements and grain mixtures for salt content (see ”Hidden Salt,” page 19).
Start with a fresh salt lick and see how long it takes your horse to consume it. An average-size horse at maintenance should take in about an ounce per day, so a 5 lb. salt lick should be half gone in 40 days if there is no other source of salt.
If your horse’s salt intake is suboptimal, you can try either putting out loose table salt or use coarse livestock salt in a small mineral feeders (weigh how much you put in so that you’re sure how much is being eaten). If this doesn’t encourage more intake, you can try our tip for jump starting good salt intake (see sidebar, page 19), or begin adding the needed amount to the horse’s meals.
Most horses will tolerate at least 1 teaspoon of table salt per pound of grain. If more is needed, you can either put it in the bottom of the horse’s feeder before feeding, leave it free choice in a small mineral feeder, or syringe it in after the horse has eaten. If you’re going to be working your horse that day, especially if the weather is hot, syringing it in after a meal (to avoid stomach irritation) is the best.
Be careful if you’re adding salt to feed. Horses won’t eat feed that is too salty, and most need to become used to having salt added to their meals.
Start with ?? teaspoon per pound and work up to tolerable levels (but not beyond optimal — see chart). When you’ve gotten the salt level in the feed where the horse will tolerate it, leave the remainder loose in a small feeder, or put it into the bottom of your feeder before you put the meal on top.
Fine salt in a feeder can be mixed with alfalfa meal to encourage consumption. In fact, adding salt to your horse’s feed simultaneously provides food as a barrier to any stomach irritation from the salt and helps protect against irritating effects on any open sores in the mouth. It also helps protect against sodium and chloride short falls as a result of exercise by having the salt on board in the intestines before the need for it arises.
If you choose to use a salt block, besides monitoring intake, consider using a plain, white salt block. Red trace-mineralized salt bricks can be OK, too, however, the level of trace minerals in that brick is not necessarily correct for a horse. Plus, you may be inadvertently overfeeding a mineral. If you want a red brick, look for one that states it’s specifically formulated for horses. If you’re feeding a blue or orange iodized block, look for a level no higher than 70 ppm of iodine.
Article by Eleanor Kellon, VMD, our Veterinary Editor.