Feeding Salt To Horses


(This blog’s header photo (above) is of a white salt block in a stall.)

When we see a salt shaker near our food, we grab it and shake it all over our plate. Unfortunately, the tiny white crystals scatter off the plate, bounce chaotically across the table and plunge off the edge disappearing on the floor below. We don’t, for a nanosecond, regret the loss of these lost particles. It’s the cost of doing dining business as long as the enhanced taste of the extra salty food hits our tongue so we can close our eyes and savor the moment we have been dreaming all the long, hot afternoon.

We stuff in more of this tasteful salt-covered food, not wanting to talk. We chew and then stuff more salted chips, fries, or meat into our mouths. Finally, after minutes pass, something inside our brain says to drink. The cold beer or soda is the icing on this moment of culinary delight. All the Covid and political problems vanish as we let out a small burp of satisfaction.

Then a thought comes to us. Did we hear or read something about eating excess salt and that it causes heart problems? We ponder and look at others around us. They don’t look like they have a heart attack. You eat more food and add more salt by dipping the potatoes into some lone salt crystals you see on your plate. In a minute, you again feel thirsty, so you reach for your glass.

Unknown to you is that you have started a destructive inflammatory process discovered in humans and in multiple lab animals big enough to get one of the largest pharmaceutical companies in the world to make a drug to stop it. There is a good possibility this process also occurs in horses. If you add granular salt to their food, you may add to their metabolic issues, including insulin resistance and laminitis.

What Is Salt?

The salt we add to food is the bonding of 2 elements: sodium (Na) and chloride (Cl). When they become “charged,” they attract each other. In the charged state, they are called “electrolytes” and written this way: Na+ and Cl- When bound together, they share and cancel their + and – charge to become neutral or stable as NaCl. This molecular combination is what we shake on our food or add to horses’ foods.

Na and Cl are in every cell and are required for life to exist. It is very soluble in water, as every cook knows. So it is in the blood and tears of our horses and us. When replacing tears or adding hydration to blood, physiologic saline is used – salted water – at a concentration of 0.9%. This mix is basically a pinch of salt in a liter (about a quart) of water.

Salt is lost when we lose any fluid, especially sweat. A complex hormone system works hard to maintain our salt levels, but any imbalance comes to our attention when this system requests more from our conscious brain. If the salt levels rise (dehydration), we get thirsty, and when salt levels get low (overhydration), we seek salty foods.

Balancing salt is very easy but has problems in extremes. For example, pigs can die from “water toxicity” when they are first severely dehydrated and then rapidly rehydrated with water. So the best and, in my opinion, the only way to keep salt balanced in horses is to have water available at all times and make solid mined salt blocks available for them to lick if they want to.

Let me explain why I think adding free salt to horses in their rations is a bad idea. First, it bypasses the self-regulation process forcing salt intake when it is most likely unnecessary. Second, if horses are like other mammals tested, adding salt to a dehydrated horse will cause inflammation to the kidneys leading to a transitory rise in blood pressure (a bad idea for horses with laminitis), and it will also inflame the islet cells of the pancreas producing more insulin (bad idea for insulin resistant horses).

How does adding Salt To Food Cause Inflammation?

The information here is for humans and lab animals that have also been tested. No work has been done on horses, but it would be interesting to get some normal values for uric acid and blood pressure as these are not routinely tested at a farm.

There will be a bit of science here. Please remember that I usually can make the complex easy to understand, so give this information a chance. It is now known in all animals tested (this includes humans) that when excess glucose is eaten, it can be converted into another sugar called fructose. This observation is HUGE so let me explain.

Starch (grain and hay), when fed EVERY DAY in excess of caloric needs, will be converted into fructose to add body fat for the upcoming winter. Grasses that are freeze resistant, as well as wheat, barley and rye, have a higher level of fructose already in the plant in the form of fructans. Glucose has a bad reputation, but in reality, it is fructose that will eventually cause the problems.

The enzyme that converts glucose into fructose is called aldose reductase and this is where the pharmaceutical company is attacking the problem. They have created a drug that will inactivate this enzyme. An enzyme makes a chemical reaction possible, and without it, the process stops.

Fuel is added to create energy within the engine of every cell (the mitochondria). It is like gas going into your car’s engine, being burned in an explosion, that gives the power to move your vehicle. The most common fuel in you and your horse is glucose. In the mitochondria, a molecule called ATP is changed to ADP and then to AMP, and these two conversions create the sparks of the energy needed to operate the functions of the cell. Then the AMP is converted back into ATP for another engine cycle. In this reaction, only about 10% of the ATP is used before the cell slows down the reaction to preserve this important molecule.

Fructose can also be used as a fuel in the mitochondria, converting ATP to ADP to AMP. So energy is made, but recycling AMP back to ATP is not done. The regulation to preserve the ATP is also reduced by consuming about 40 to 50% of the ATP, leading to the cell’s mitochondria exhaustion. So what happens to the leftover AMP? It becomes uric acid (UA). This stuff is really interesting.

UA in men is known to cause gout because all purines cause gout, and UA is one of the best. What researchers also found out is that UA inflames the kidneys. This reaction is the direct cause of hypertension (high blood pressure) in humans and lab animals. Removing fructose by blocking the enzyme aldose reductase reversed hypertension and secondary heart disease in experiments. It completely reversed it! Could hypertension be associated with inflammation in horse hooves (laminitis)? It certainly wouldn’t help it. But there is more.

UA also inflames the islet cells of the pancreas that makes insulin. They found that humans and lab animals fed excess glucose daily created more fructose, leading to all having metabolic syndrome. This included high blood triglycerides, obesity, fatty liver, insulin resistance and diabetes. But when researchers blocked aldose reductase in experiments, the indicators of metabolic syndrome that I mentioned completely normalized! Obese humans and lab animals became thin with all parameters normalized.

Now you can see the value of creating a drug that blocks the enzyme – but wouldn’t it be better to eliminate sugar from the daily diet? But that isn’t the question for this blog. So why am I talking about the conversion of glucose to fructose in a blog about salt? I thought you’d never ask.

Salt Plus Dehydration Activates Aldose Reductase

Research has shown that a low salt diet is “heart healthy.” It turns out that for some unknown reason when salt is eaten WHEN THE BODY IS DEHYDRATED, the higher saturation of salt in the blood triggers aldose reductase to convert glucose into fructose! If you drink the beer/soda/water BEFORE eating the salted food, the enzyme is not activated and uric acid is not created. But as soon as you become thirsty, the enzyme is already at work.

No one knows exactly why this salt/hydration triggers the enzyme, but it is clear that it does. Because of this, I always drink some water before a meal. But does your horse? Is your horse hydrated before you feed a meal with added salt? While we have no one looking for this enzyme in horses and no one is measuring UA, blood pressure or any other parameter, I feel better just assuming that I should NOT feed loose salt to horses. Again, here are the reasons:

  1. Horses usually don’t need additional salt, but if they do, they will self-regulate it by licking it and drinking water when their body says.
  2. Adding salt to a dehydrated horse may have the same negative effects in humans and other mammals – Increased blood pressure, high blood triglycerides, fatty liver, insulin resistance, diabetes and obesity.

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  1. Hi Doc T,
    I just dove into all your blogs on equine nutrition and have been reading through the comments too as I find them very educational. As someone who was raised to grain and supplement, supplement, supplement, this has all been very eye opening. Anyways, I do have a quick question for you. In terms of protein, I’m having a hard time finding soybean meal in my area and I was wondering if beet pulp could replace soybean for your no grain diet? If not, I’ll just do some more digging, but I had to ask, as that is a protein source much easier for me to find. I’m also curious, would adding a little cubed or pelleted alfalfa be bad if I’m feeding a straight grass hay with really no way pasture available? I apologize if you’ve answered these questions before or covered it and I missed it in the blogs. Thank you for all your help and for all the free education as well!

    1. I understand that the word “protein” is confusing. To help, I now divide protein into 3 categories: 1) low quality protein, 2) good quality protein and 3) high quality protein based on the amino acid composition and the bioavailability of the amino acids.

      All grass and legumes have an incomplete amino acid profile and the amino acids are absorbed at 50%. Therefore grass and legume pasture and hay are “good quality” protein.

      Soybean meal has all the essential amino acids and is absorbed at about 80%, therefore it is a high quality protein. It will not only help rebuild the lost muscle of the top line, it will rebuild the proteins of the hooves, hair coat and all the unseen proteins such as neurotransmitters, enzymes, hormones and vitamins. SBM is about 48% protein so 454 grams (1 pound) x 48% = 218 g of protein of which 80% is absorbed = 174 g of high quality protein. Added to about 450 grams of good quality protein from 20 pounds of hay and pasture a day = 624g total absorbed protein. the goal is 0.5 to 1.0 G protein per pound of body weight so for a 1200 pound horse, the 624g is just over the minimum daily protein needed for horses.

      Beet pulp is is between 7 and 10% protein with an incomplete amino acid profile (valine is absent) and with a lower bioavailability of amino acids when compared to alfalfa and SBM.

      The conclusion here is that feeding the byproduct of the sugar beet industry in a very poor way to get protein into your horse. It is a source of more calories with a reported lower glycemic index – but even with a low glycemic index, it is still a high source of carbohydrates. This will make using the available amino acids from SBM more difficult.

      I do not recommend feeding any byproducts both in the health of your horse and on the principle that you are paying them to get rid of their waste. This may be fine for feeding animals destined for our dinner plate but not for painting a long health span for our horses.

  2. Hey Doc T,
    You’ve been floating my horses’ teeth for years now. About 9 months ago, I was finally able to get SBM and added this to their grain/supplement free diets at the initial 1 #/day. I’ve since cut them both back to 1/2#/day. One of them will never touch salt blocks so A few months ago I started adding 1 tsp. of salt/day to soaked T&A cubes mixed with SBM in the morning. The last 2 weeks the youngest (13) has had huge uptick in urine production without an relatively equal amount of water consumption. Vet is coming here on Thurs for shots and checkups so I’ll see what he has to say. I cut the salt out and she is now only getting 2 oz. (by volume)of SBM/day. Is it possible that she is getting too much protein and this is causing her kidneys kick into overdrive? Should I cut out the SBM on this one completely? The 25 year old still has shown any improvement in her top line but I think it may be age related. Neither horse gained weight on the SBM but both are still overweight. Still haven’t been cleared to ride and even at 6:00 AM the temp is around 80 and the humidity is above that so lunging will be unpleasant for us. Value your opinions on my horses situations.

    1. A lot to cover here so let me chunk it.

      1) Some horses take to soybean meal (SBM) slowly and increasing the amount slowly seems to work. Some take several weeks. By far, the majority of horses love it so be patient.
      2) 1 pound of SBM per 1200 pound horse per day gives the horse access to all the essential amino acids (EAA’s) and therefore is a high quality protein. Legume and grass hay and pasture are only good quality because they do not have all the EAA’s. 1 pound of SBM when added to 20 pounds of hay plus pasture per day raised the total ABSORBED protein to a little over 0.5g protein per pound of body weight. The goal is between 0.5 and 1.0g per pound so adding 1 pound SBM plus pasture/hay in a 1200 pound horse gets the daily intake to the minimum. Therefore you are not “overfeeding” protein.
      3) Salt will create an osmotic draw and therefore will increase urine output though 1 teaspoon once a day seems low to cause any change. Water consumption needs to include the water added to the pasture from our abundant rains. But the only way to get an answer for the reason for an increased urine output is to analyze the kidney function through blood and urine analysis. Your vet should be checking both though urine is rarely checked because getting a urine sample on demand is time consuming and difficult. But a urine sample is necessary to evaluate kidney function.
      4) Added protein should not increase urine output volume and should not “kick the kidneys into overdrive.” Excess protein is converted into glucose with increased urea in the urine which will create a stronger odor but not increased output.
      5) I think there was a typo when you said, “The 25 year old still has shown any improvement in her top line.” I think it is missing the word “not.” Top lines take about a year to start showing improvement in most horses but I have seen it take longer in horses over 20 years of age.
      6) Adding SBM to horses who are getting access to more carbohydrates than are needed in a day will trigger an interesting phenomenon seen in humans. It is based on the insulin to glucagon ration (I:G). In humans eating a diet with excess carbs in it (over 100g per day), the I:G is about 4.0. When carbs are reduced to below 100g, the I:G falls to about 0.8. Insulin causes fat to be added to the body and it surpasses glucagon. When insulin is absent (no carbs in the diet), glucagon is allowed to do its job which is to convert body fat into fuel which leads to fat loss. An I:G ratio of 4.0 will cause added body fat and is the reason behind the obesity epidemic in America. And I:G of 0.8 will cause weight loss due to fat being used for fuel. Here is the really interesting part. When a diet is in excess of daily carbohydrate needs and has an I:G of 4.0 AND THEN PROTEIN IS ADDED, the I:G rises to 70!!! This is why your horses are not losing body fat and some actually gain weight.
      The only way to reduce body fat is to reduce access to carb intake and for horses this means limiting the starch they are eating. Most horses only need to eliminate grain to do this especially if they are young. But older horses or obese horses with metabolic syndrome (insulin resistance) also need to limit their starch intake by restricting pasture, hay or both. This is where the extra protein helps.
      7) The “Protein Leverage Hypothesis” states that the body will prioritize protein intake over the intake of carbs and fats. Basically humans are not satiated until their protein levels are met. I have seen horses become satiated when they are fed high quality protein as all the EAA’s are then consumed. Muzzles are removed and ponies lie in their hay. Food aggression is eliminated. Adding enough high quality protein will help reduce the “starvation” effect of limiting hay and pasture.

      I hope this all helps in understanding your horses and I hope the vet was able to explain this to you. See you for floating sometime soon!

  3. “Improving gut health, reducing gut inflammation and keeping fiber moving” Please tell me what you recommend to do this. Currently most of my horses eat an orchard/alfalfa mix hay, Alfalfa Bermuda pellets and Safe Choice Senior feed. They get Smart Pak Bug Off Ultra, and some get Smart Pak Comfort blend, and some get Forco too.

    1. Terri – Please read all the blogs on nutrition to understand how the gut microbiome works and how to improve it. Be sure to read all the comments too as most questions are answered there.

      All grain is inflammatory so removal of the senior feed is step one. You will need to read the ingredients of the Smart Pai supplements. I don’t know what “Forco” is. I am aware that the flies are an annoyance but to improve gut health, all things other than forage, water and mined salt need to be removed.

      Most horses are protein deficient so the addition of soybean meal will correct this. Instructions are in the blog.

      My apology for this short answer but feeding horses is simple but understanding why takes a bit of work. I have it organized in the nutrition course which I would like you to consider enrolling in. Otherwise all the information is free on this website. Thanks, Doc T

  4. I have been adding loose salt to my horses feed for years. I started doing it becuse someone suggested it after losing one of my horses to Colic. If you add it, then they drink more water and lessen the chances of Colic.
    So basically I was doing it out of fear and not knowing that there could be other problems associated with feeding the loose salt.
    Stopped adding salt as of this morning.
    Thank you for this article

    1. Hydration is very important in preventing colic but there are better ways to do this. Improving gut health, reducing gut inflammation and keeping fiber moving is more effective than adding salt to increase water consumption.

      Thanks for commenting and changing your approach.

  5. I have a horse that sweats just standing in his paddock. And I don’t meant a little here a little there. He looks ike I just hosed him off. I have never seen anything like it before. Wish I could post a pic so you could understand. I have a Himalayan salt block hanging in the stall and just started electrolytes in his meal. He does have high water consumption and high urine output. Should this be of concern. I have to also add no other horse. ( 12) in these paddocks remotely sweats like him if at all. He’s a 6yr old arab not that that matters.Suggestions????

    1. Please consult with your vet. Blood and urine samples should be analyzed. 6 year olds usually do not have a dysfunction of the pituitary but he may have some hormonal issues causing the high urine output with a compensatory high water intake. He may also have a kidney issue where muring made is not concentrated (medullary washout).

      A detailed history needs to be taken to include his diet, the timeline of indicating signs, the association with yearly changes such as temperature and pasture grasses and the response to adding salt and electrolytes. This is not something that can be discussed here. You need to call your veterinarian and execute a logical plan.

      The most important question to ask is this – how does he feel? Is the excessive sweating causing any problems such as thumps or muscle tremors. This must also be included in the detailed history along with any other relatives (parents, siblings) showing similar signs.

      Sorry I cannot help you with this here.

  6. I have always worked on the assumption that salt blocks are for cattle, who have raspy tongues, and loose salt is for horses who have tongues like ours. The horses in my pasture, out 24/7/365 get loose salt in a bucket hanging in their run-in sheds. Even in winter, when the snow blows around, the salt is eaten and enjoyed by all 4 of them. All water troughs are drank down and I never have to worry about dehydrated horses even when it is + 35C. I would never put a salt block near my horses, only loose salt. Oh, and the ages of the horses, 35, 31, and two 20 year olds.

    1. The assumption of tongue “raspiness” is curious to me. Horses use their tongues to harvest grass just like the ruminant cousins. Use the slow motion video capabilities of your smart phone and video them licking the ground as they lift the grass into their mouth and snap it off between their tongue and top incisors (or gum if they are missing these teeth). In fact, the wearing of the incisors and the creation of razor sharp edges on the cheek teeth is caused by the stropping by the tongue. From this I would be more likely to think the toughness of the horse tongue is more like any other grazing animal rather than being similar to a non-grazing animal such as humans.

      In almost 50 years I have seen a lot of horses consume salt in the block form with never an unjust or condition caused by it.

      The purpose of this blog is to show what might be happening to horses with sugar caused inflammation such as laminitis and equine metabolic syndrome. Horses kept like horses, as they are at your farm, will live a long time without these diseases caused by confinement and poor nutrition. Adding loose or hard salt is not important for your healthy horses. Allowing for constant access to clean water is imperative but on some farms is not always true.

      Thank you for your comment here. Loose salt will work for you because you are caring for your horses correctly. In the whole world I wish this was the same for all horses but I know it is not. I believe forcing salt into a horse that does not need it by adding it to their ration may actually harm some and that is the purpose of this blog.

  7. Hi Dr T. Fascinating blog. My view on adding salt is based on my experience with Amadeus having blood in his urine. Long story short, calcium carbonate precipitating in the bladder Causing severe chafing, likely due to pH issue caused by imbalanced nutrients in the hay. No pasture available where he lives. He won’t use salt lick. Daily NaCl has resolved the problem. I’m sure you recall all of this as you are reading my response. Now I am going to have to pick your brain again next time you visit! Stay well!

    1. And then there is Amadeus….

      Here the salt is being used to treat a condition that no one understands why is occurring in your horse. The other horses on the property are not affected so this is an individual response to the hay consumed rather than an environmental agent affecting all horses. Your horse actually supports the theory that minerals are well regulated including calcium, sodium, chloride and others in almost every horse. When this regulation is altered biologically, an adverse reaction occurs.

      In your horse, calcium was abnormally excreted in the form of calcium carbonate (formula CaCO3). This compound (CaCO3) is commonly applied to fields as agricultural lime to support healthy growth of the grass. It is also commonly found in horse feeds as an antacid or as a calcium source.

      In your horse’s bladder, CaCO3 was somehow being excreted in the urine instead of being converted to Ca++ and CO3– The Ca++ could then be used for bone and muscle and the CO3– would add H and eventually be turned into H2O and CO2. Aren’t we all glad that we don’t need to think about this? It just happens, except in Amadeus. For your horse, the bladder was getting “limestone scale” no different than on surfaces of the bathroom shower.

      In swimming pools, scaling is averted by changing the salinity of the water. As salinity increases, the dissolution of CaCo3 to Ca++ and CO3– increases. In your horse, the salinity of the blood or urine is not sufficient enough to make this reaction occur but by adding salt to the diet, the Ca can be dissolved and used and the H2O and CO2 can be excreted.

      Adding salt in your horse’s diet is a treatment and therefore is needed to prevent the blood seen in his urine. We don’t have a reason for salt triggering aldose reductase but I would suspect that in your horse the salt is being effective in normalizing the physiology. I would not worry about it causing the increase in uric acid unless you gave more salt than was needed to neutralize the CaCO3. All you need to do is pay attention to him and so far, all seems well with him as you use the salt wisely.

      Thank you for speaking up on this post because we all need to recognize that there are so many individual reactions to the same environmental factors. Further, no one is researching much with horses, especially on the chemistry of horses, without an agenda of selling horse owners something. However, I am grateful for you adding your comment here as it helps us all understand the complexity of life and the individual variations that can occur. See you in a bit!

    1. I’m not sure of “kik nfd” – I’m guessing “kind of.” LOL – spell check!

      According to the research in humans, if you consume salt and then become thirsty then you were dehydrated before the salt meal. So I would go with “kind of.” Digging deeper, the researchers actually measured the blood concentration of salt as well as the osmolality of the urine and they have accurate results. There are over 800 papers on this subject so if you want, you can dig in to get a more accurate answer. Let’s look at horses –

      In many barns the first thing in the morning, the lights go on and the ration (grain or no grain) is given with added salt. It would be logical to assume these horses are slightly dehydrated unless they drink their fill of water before feeding them. The same goes for horses running in the field and brought in for feeding.

      Another commenter here explained that her horses have free access to salt in the field. Assuming they also have free access to water, I would assume these horses are hydrated before consuming the salt.

  8. I know we disagree about loose salt and block salt, but I do know when I fill the buckets kept in every paddock area my horses are in they all are in them immediately. I will assume that their bodies are requiring the added salt, or something, as I mix my loose salt with diatomaceous earth and have been feeding free choice for over 30 years. I have 17 horses and not a one that won’t rattle that bucket when it’s empty. Since I also have no health issues with my horses, who I might add are never grain fed, I agree that if given the choice they tend to keep everything regulated just fine.

    1. I think we agree more than disagree. Horses will self regulate. I do ask a lot of questions though which usually raises more questions more than give answers. For instance:

      1. Why do some horses on a farm ignore salt while on other farms they lust for it?
      2. Why does this happen in a herd on the same farm?
      3. What kind of pasture maintenance is performed (testing and fertilizing with minerals)?
      4. What is the ratio of horses to pasture area?
      5. Is this seasonal with increased consumption in the summer?

      And there can be more questions. In this blog I wanted to raise the issue that in metabolic horses or horses with laminitis, adding salt may exacerbate these syndromes. However, if your horses are doing fine then don’t change because of what I say. Hopefully, some of these questions I’ve asked here can be thought upon and considered in your own situation.

  9. So, if one of my horses never touches his Himalayan salt lick, I don’t need to worry about it? And I mean never, it stays dusty. (I have been adding salt to his alfalfa cubes, so thank you for this post.) :0

    1. Does he show any signs of a mineral deficiency? If not then he is 1) obtaining sufficient minerals from his food and 2) he is recycling his minerals correctly.

      Most horses either ignore salt hating in the stall or only occasionally lick it so it lasts a year or more. This is normal. Other horses, like some commenting here, lust for their salt. This is abnormal yet it rarely causes a problem. In some horses, it can cause “medullary washout” of the kidneys resulting in abnormal urine output and abnormal water intake. I believe these are partial cases of diabetes insipidus (which many call “Cushing’s disease or PPID).

  10. My horse will eat the salt block rather than just licking it once it gets small enough to bite pieces off. He’s on a diet of green irrigated pasture 16 hours a day and additional timothy, along with a small feeding of alfalfa pellets rehydrated at night for additional protein and some flax seed. Why does he do this?

    1. Is this seasonal? Does he sweat a lot? Is he exercised a lot? Is there sugar in his salt block? Is he growing or a senior? These are the types of questions you and your vet need to go over to fully understand why your horses has an increased appetite for salt.

      Please read my blogs on protein in the nutrition section of my blogs. Here you will understand why the diet your horse is on is deficient in high quality protein and could be another piece of the puzzle. Hay and legumes (alfalfa) do not provide all the essential amino acids needed to build all of the proteins required for thriving in life. I recommend feeding a minimum of 1 pound of soybean meal a day per 1200 pound horse. I do not recommend adding amino acids in a can / bag.