Hormesis, Hay And Horses

⬆︎(This blog’s header photo is of a modern 6-wheel tractor tedding the hay field before baling.)⬆︎

In our Facebook group, “The Horse’s Advocate,” a member was concerned about her horse. The “diet” is feeding only pasture and hay, salt and water plus the addition of soybean meal (SBM) to replace the lost amino acids. Here is her post:

My horse just came down with a bad case of grass founder on all four feet for the first time….I have been doing this diet for a year now…got her off of grass and feeding grass hay ( Bermuda & orchard/fescue hay)….she loves the SBM but should i cut it out or maybe decrease?

The following will be a long and scientific answer, but in a nutshell, horses need hormesis. This is the cellular process of resting which helps to clean up cellular debris, remove damaged cells and help the mitochondria switch their fuel source (mitochondrial flexibility). PLEASE read this entirely, even though it will sound too far advanced for most of you. I will summarize along the way in the gold-shaded sections and, at the end, introduce you to a theory of why horses are getting laminitis even though they are off of grain.

The Key Point

The key point of this article is that any animal (humans, horses, dogs, gerbils) who eats glucose in any form (starch, soft drinks, candy, byproducts of grain and sugar beets) in excess of their needs on a DAILY basis will become inflamed at the cellular level, develop metabolic syndrome and become ill in one way or another. Obesity is evidence of inflammation, and chronic protein deficiency is secondary to this (sarcopenia in humans or poor top line/hay belly in horses – same thing).

Current research in humans and lab animals has discovered the development of an enzyme called aldose reductase in people and animals who eat abundant glucose every day of their livesMany enzymes are developed in animals when certain continuous food intakes require the animal to take action. An example in humans AND IN HORSES is the development of alcohol dehydrogenase when alcohol intake is daily. We did this study on ponies in the 1980s at Cornell because research on liver disease from hepatitis had lots of money. We fed them 100% (200 proof) alcohol in their meals and measured for alcohol dehydrogenase, which was absent at the start of the test. This enzyme is not in children or adults who don’t drink alcohol. Alcohol is a toxin to the body (sorry, folks!), so the body develops this enzyme to turn the alcohol into water. This is observed as “tolerance.” When I drink one cup of my wife’s homemade, hand-whipped egg nog on New Year’s Eve, I become goofy, and with 2 cups, I’m asleep because I don’t drink alcohol any other time.

Aldose reductase is a responsive enzyme developed by the body when glucose intake is daily and non-stop year round. All foods act as signals, and the signal from continuous glucose intake is that winter is coming. Remember, all starch is a chain of glucose molecules (Grazing Not Browsing -Decomplexicating Equine Nutrition Part 1 of 12). Starch is found in growing plants but is gone in dormant plants, especially after rain or melting snow. When consuming food with starch, the signal to animals (in this case, horses) is that winter is coming, and the response is, “We need to store more fat!” The process of making energy within the cell changes, and so does the fuel.  Aldose reductase converts glucose into fructose.  These are sugars but cause a different pathway in the mitochondria’s metabolic pathway. This alternate route is inflammatory but is necessary as it is usually temporary. Winter is followed by spring, and food becomes abundant once again.

Summary – Glucose is the sugar of starch found in grains and the nonstructural part of plants. Fructose is the sugar of fruit, but it is now discovered that animals can make fructose when they need to add body fat for winter.

The chemical structure of the two sugar molecules.

Glucose And Fructose

First, let’s describe glucose and fructose. Both have 6 carbons, 12 hydrogen and 6 oxygen atoms but the way they are put together is different. Glucose has little sweetness, so the ripe fruit converts glucose into fructose to encourage animals to eat and spread the seed. With aldose reductase, the same is done within animals.

When glucose enters the metabolic pathway (the Kreb’s cycle) it causes ATP (adenosine triphosphate) to lose one of its 3 P (phosphorous) atoms to become ADP (adenosine diphosphate or 2 P). It then does it again to become AMP (adenosine monophosphate or 1 P). This process is conservatively limited by phosphofructokinase, so only about 10% of the total ATP is used. Beyond this point, mitochondrial exhaustion begins (glucose metabolism is turned off, glycolysis is started), and the mitochondrial metabolic pathway is limited. An enzyme called AMP kinase is triggered, which adds back the P atoms so that the AMP becomes ATP again and is ready for the next use. A side note here. The drug metformin enhances this AMP kinase and is used to increase intracellular ATP, thus countering mitochondrial exhaustion.

Summary – When glucose is the fuel, energy is created by the engine inside the cell (the mitochondria). A recycling program then takes over well before it is needed to restore the necessary chemicals to make more energy, so the cell is always ready.

But what happens when fructose is used as fuel? After the ATP converts into AMP with the loss of the 2 P’s and the creation of energy, the path goes in a different direction:

1) The enzyme used to digest fructose (fructokinase) causes up to 50% ATP depletion (greater mitochondrial exhaustion).

2) The loss of ATP causes hunger and thirst. It increases body fat (energy storage) and glycogen (glucose storage) because glucose is no longer metabolized by the mitochondria but rather through glycolysis which does not use oxygen. This is a survival mechanism in all animals facing starvation, resulting in increased body fat and the start of metabolic syndrome. The excess glucose from starch has to go somewhere as it is not being used and the best storage for it is body fat and liver fat (leading to non-alcoholic fatty liver disease in humans).

3) The satiety hormone leptin (not lectin) is blocked by increased glucose intake, further increasing hunger and food intake. The point here is that as the energy factories are shutting down, the continual sugar input needs to be stored because when the food stops (winter), the animal will need to get the energy from somewhere.

4) The last point here is that instead of ATP kinase putting the P atoms back onto the AMP molecule, the enzyme AMP deaminase turns AMP into uric acid (UA). This is significant in humans, and lab animals studied because UA is the cause of inflammation in the kidneys and the islet cells of the pancreas. So what does this do to their health? A lot!

Summary – When fructose is the fuel, energy is still created inside the cell, but supplies’ reserves are greatly reduced, AND the recycling program shuts down. In addition, another chemical is produced (uric acid) that is not normally found. This is OK in a short-term situation such as a season, but when it continues, it affects the health of humans and lab animals and, I presume, horses too (but nobody is researching this in horses).

The islet cells of the pancreas make insulin. When inflamed by uric acid, the islet cells make less insulin with subsequent insulin resistance and type 2 diabetes in humans (from the paper “The association between elevated serum uric acid levels and islet β-cell function indexes in newly diagnosed type 2 diabetes mellitus: a cross-sectional study” –  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5846453/  –  The conclusion is quoted here: “In our study, insulin resistance and insulin secretion increased with rising serum UA levels in both men and women.”)

UA also inflames the kidney, the regulator of blood pressure (hypertension). A direct correlation exists between high blood UA levels and hypertension in humans and lab animals. This means in humans, and all animals tested that, a continuous glucose intake throughout the year causes higher fructose in the diet. This causes high blood uric acid levels, leading to insulin resistance, high blood triglycerides, fatty liver, obesity, metabolic syndrome, and heart disease associated with hypertension. To drive home this point, when animals are given a medicine that blocks the enzyme that creates fructose from glucose OR when they are placed on a very low glucose and zero fructose diet, hypertension and all the signs of metabolic syndrome are reversed and normalized! Calorie restriction is what this is called in humans and is the leading theory behind increased longevity and, more importantly, an increased health span.

Summary – Reducing the availability of starch and restricting it to only what the horse needs to survive the workload and the seasonal elements will eliminate inflammation, which is at the heart of almost every problem we see in our horses.

Now The Hard Part For Horse Owners

Hay is last summer’s grass. In the 1950s, very few people owned tractors in industrialized nations. The grass was cut with mowers pulled by draft horses, picked up by pitchfork, pulled into barn hay mows with a claw on a rope using pulley systems and finally distributed in the loft by hand and fork (search on YouTube for “making hay with horses”). In the 1960s, the US started the Eisenhower Interstate system of roads (https://www.fhwa.dot.gov/interstate/history.cfm). By 1970 hay was being made into bales and distributed by trucks along high-speed roads to small distribution centers we called farm stores. The concept of horses eating hay then is only about 60 years old. Originally hay was used to feed livestock during the hard times of winter to help them survive. Now horse owners believe hay is a staple and must be fed ad lib every hour of every day. While I have been one of the biggest proponents of feeding horses continuously, as suggested by all horses lacking a gall bladder (very few animals are born without this), I believe I was wrong.

It has been demonstrated by the observations of Dr. Katherine Houpt, VMD (Cornell professor emeritus) that horses chew between 10,000 and 40,000 chews per day. The assumption that one chew equals 1 second means 10,000 to 40,000 seconds per day are used to intake food. There are 86,400 seconds in a day. Using math, a horse is only eating between ⅛ and ½ of the day. While this makes logic for me, I decided to dig deeper. There is science behind what happens when we do not eat. However, we first need to assume that every cell in the body (all animals) requires energy at every moment of life – like a car needs fuel converted into energy to run, or it just stops. We must also assume that all animals don’t take in the raw materials constantly, but they go through a process of taking in a meal. Then, when they are not eating, these raw materials go through the process of digestion into fuels, transport and distribution of these fuels, consumption of the fuels and storage of unused fuel.

Summary – The creation of energy by the cells happens during every moment of life. Taking in the materials (food) needed to make fuel for this process is intermittent both during 24 hours AND during a 365-day year. To buffer this inconsistent intake of food, the body stores fuel as body fat. The more food is consumed beyond daily needs, the more body fat develops. When this occurs every day and year-round, the bad side of things happens, such as disease.

For this part of the discussion, we will call the cell’s mitochondria “the factory.” Fuel goes in, and energy comes out along with the waste. The better the fuel, the less waste and the less work the cell must do to clean up. But with more waste, the clean-up crew starts to complain. With more complaining, management restricts the tools needed to clean up. Why? Because management is too busy worrying that winter is coming. They have too much glucose, so they start to change how energy is created as they look for ways to store the excess. They even begin to convert the amino acids into more glucose because the dangerous signs of a very long winter (an ice age) are coming. Survival is the highest priority, while clean-up, maintenance and repair are low priorities. The means justify the ends. We will die trying to save the ship.

Normally during winter, when glucose availability diminishes to near zero, the cell starts using the more efficient fat fuel (The High Fat Diet – Decomplexicating Equine Nutrition Part 7 of 12). The horse takes fat stored as body fat and converts it to ketone bodies which are 20 to 28 times more efficient in producing energy with a lot less waste. As a result, the clean-up crew goes to work with vigor. After all, if there is no end to cleaning up horse poop with no time left to ride, what is the incentive to keep working? But with less poop, the cleaning becomes fun, right? With less worry, management has time to bring you coffee and food for your morning break! Keep dreaming.

Maintenance and repair become a priority now that there is extra time and energy within the cell. This process is called hormesis. The cell uses many techniques to repair things, and one of those is called autophagy. “Auto” means self, and “phage” means eat. The cells literally eat all the waste material and remove it from the cells. Another process is called apoptosis which is the scheduled death of a cell – like the euthanasia of a very old horse unable to get up off the ground. Many more processes are used every moment to repair damaged proteins (heat shock proteins) and DNA and RNA (sirtuins). But let me stay with the simple explanation of hormesis and horses.

In winter, horses are supposed to lose body fat while maintaining muscle. When we see this fat loss, we must say, “My horse is repairing and maintaining and will remain healthy and sound because I am seeing hormesis at work.” If winter becomes harsh with very low temperatures and unbearable wind and snow, add hay. That is what it is for. Otherwise, being a good horseman requires us to acquire a fine eye for when to add food beyond what they find in the pasture. As good stewards of our horses, we need to recognize the importance of hormesis and know they need this metabolic rest period seasonally.

I can hear all of you say that you have no pasture. I see that. Adding hay is a requirement, but don’t feed it 24 hours a day. Limit it to what the horse needs to maintain their body weight. For all who are competing, use your eye. As the workload increases, then add more energy. About 100 years ago, the work required of horses to plow and harvest for all the people moving to the cities was life-threatening to the horses. They lost too much condition, so farmers started to add grain to compensate. Does your horse work that hard? Then adding grain in the form of whole grains probably won’t bother them as they are consuming the excess glucose and NOT triggering the production of fructose. But if your workload is less, the need to feed glucose 24 hours a day and seven days a week is unnecessary and also harms them at the cellular level.

Summary – Food availability for horses living in nature ebbs and flows. The body needs an abundance of food to prepare for the time when food is scarce. They build reserves with the excess food knowing that tough times are ahead, so they are willing to pay the cost of doing this (inflammation). The cells clean up and repair when food is scarce (winter). This needed repair period is missing in horses in the flow state of abundant food availability – and our horses are becoming ill from it.


Carbohydrate dependency (Carbohydrate Dependency – Decomplexicating Equine Nutrition Part 6 of 12) is the root cause of ills and unsoundness in horses today, with the secondary development of chronic protein deficiency (The Importance of Protein – Decomplexicating Equine Nutrition Part 8 of 12) that I talk so much about. It is very important to understand that if glucose is fed continuously, the amino acid deficiency will be more difficult to restore. In laminitis, feeding soybean meal will help to restore the connections between the hoof and coffin bone. But I think it is more important to eliminate any inflammation first and foremost. Based on current research on humans and what I have said above, I have a hypothesis. There is so little known about uric acid in horses, but we know that the hooves are a vascular bed of fine capillaries. If UA causes inflammation of kidneys with secondary effects on blood pressure, then would it make sense that UA also causes inflammation with the capillary bed of the hooves? The same thought of inflammation of the islet cells and the increase in insulin resistance (IR) may also be associated with this fine mesh of blood vessels. I am sure chronic protein deficiency leads to decreased cystine disulfide bonds in the hooves making their structure and attachments weak. Therefore it is very important to replace this lost amino acid by adding methionine (which converts to cystine and makes up 26% of the hoof). However, in every case of laminitis, there is usually insulin resistance. Therefore, I believe that IR is secondary to the increase of blood uric acid  (this may be a new idea in the horse world). High blood UA is directly related to activating AMP deaminase, which converts AMP into more UA. The increase of AMP deaminase is directly related to the increase in fructose made from the conversion from glucose by the enzyme fructokinase developed in animals on a high glucose diet.

Summary – Feeding glucose (starch) every day of the year leads to insulin resistance, metabolic syndrome and hypertension in humans and other mammals tested. This is probably all due to the discovery that glucose is converted into fructose with high uric acid production in the blood. This inflames the kidneys and pancreas with subsequent illness. Testing in horses has not been done, but I propose the possibility that this same process leads to the inflammation of the laminae of the hooves.

Excess glucose > conversion into fructose > increased blood uric acid > IR, diabetes, hypertension, fatty liver, obesity and other signs of metabolic syndrome.

I hope this lengthy discussion will help you understand why your horse foundered on grass. There is so little known about these enzymes and UA in horses and their role in laminitis. I think this will help you look at it from a fresh perspective. For me, these are relatively new findings over the last ten years of research and NOT in my textbooks in the 1980s. We all know there is an epidemic of obesity, diabetes, metabolic syndrome, non-alcoholic fatty liver, dementia and heart disease in humans. We also see obesity and metabolic syndrome in our horses in levels I did not see 50 or even 30 years ago. And it is getting worse.

Read these and blogs from others. Avoid agenda-driven information where they are trying to sell you something. You will find that simplicity works in most cases – that pulling teeth is a last resort.

I hope your horse fully recovers, but you must decrease active inflammation and remove all causes of future inflammation. This will require you to rethink how you feed your horse and throw out all you were taught, as it is not working with this horse. Other horses may be OK with feeding hay daily or grain, but more horses are being pushed to the edge. I hope this long-winded discussion will let you know that, at least in humans, the answers to metabolic syndrome seem imminent. Pfizer is working on a drug to block aldose reductase, which will soon be released. I can see it being used in horses. Allopurinol will block the production of UA from AMP, and metformin will encourage the phosphorylation of AMP back into ATP. Some vets have tried these medicines, but not many qualified studies use them in horses. Be sure to ask your vet about them as you proceed. Thanks for being a part of this group and searching for answers. Doc T

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    1. The outer covering of all grains contain proteins called lectins that, for the most part in humans, cause damage to the lining of the gut. Please read the blog on lectins. In human food production the outer layer of rice is removed to prevent this cause of gut inflammation. What is left is rice bran which the owners of either had to throw out or they needed to make money by selling.Horse owners were very willing to purchase it to become the rice makers disposal for them.

      Most Asians eat white rice for a reason. And why would we feed to horses a byproduct of the food industry? Rice bran, wheat middlings, soybean hulls and distillers dried grains – all by products. Add to this that all foods are seasonal yet they are fed to horses every day of the year.

      Remember that all soft seeds are plant babies that are meant to be spread in the wind or on the wet skin of animals to germinate elsewhere. When they are eaten they die. The purpose of lectins is to sicken those eating them. A good example is wheat gluten which any celiac will tell you they have zero tolerance for. Another is wheat germ agglutinin which mimics insulin and blocks the insulin receptor site on cells – one of the causes of insulin resistance. For these reasons I do not recommend grains or grain byproducts such as rice bran for horses.

        1. Bran is the outer shell of a grain and is the byproduct of the milling of grain. Rice bran is what is removed to make white rice from brown. There is about 12 to 13% oil in rice bran.

      1. I’ve been enjoying reading your blogs, and would like to try using SBM, however the local feed stores don’t seem to know if it is dehulled or not… Are most forms of SBM sold for livestock feed dehulled, or does it matter? Or is there a brand commonly sold that I should look for?

        1. All soybean meal (SBM) is de-hulled and the oil extracted either with solvents or with pressure. Then it is heated to deactivate the trypsin inhibitor (often called “toasting”). It is an ingredient so there is no “brand” but rather a farm name. SBM for cattle and swine is the same used for horses.

  1. I have a 15 mo arabian quarter paint which is wild and was raised on mesquite trees and pasture grass in southern Arizona. We have had her for 2 months and she will not eat alfalfa hay so we have been feeding her alfalfa pellets and grains. I was referred to Dr. T by Caroline Beste and I am immediately took the grain out of her diet today, however I was unable to find SBM and purchased Rice Bran Meal, will that be okay after the 2 weeks of just hay, salt and water? Also, I have never soaked the alfalfa pellets, should I with the meal? We started her again this week with alfalfa hay and eventually she will eat it. We have no pasture hay and she is in a round pen until we can halter train her. Lastly, you say to give her himalayan or rock salt but I also read in another one of Dr. T’s blog to not add salt to her diet?? We had a salt block in with her but she hardly ever used it so we started sprinkling about 2 oz a day on her feed. Thank you.

    1. Attilia, keep looking for the soybean meal (SBM). It is abundant and commonly used in cattle and hogs and poultry. I have people around the world who have found it including Kenya, Australia and throughout the US. Some travel an hour to get it.

      Please read all the blogs on protein to understand the importance of protein especially the high quality protein with all the amino acids required for optimum health. It is also important to understand why horses have become protein deficient.

      Rice bran I’d NOT a high quality protein source and is NOT a substitute for SBM.

      Some horses can choke on pellets so most people soak them. If you don’t soak them, be sure he is hydrated and only offer small amounts at a time. An alternative would be alfalfa cubes. But alfalfa is not as important as just feeding any forage (grass hay and pasture). Adding a legume adds some calcium and good quality protein but it does not give all the essential amino acids nor are the proteins absorbed as well as SBM.

      Offering mined salt in block form is good. I make a case against adding loose salt to the feed to horses with metabolic syndrome or laminitis. I believe forcing salt into a horse is unnatural as well. If they don’t want to lick it then they are probably not mineral deficient. Please read the blog on supplements which includes minerals and electrolytes.

      Thank you for giving this diet a try. Removing the grains will help your connection with this horse beyond your expectations. Doc T

      1. Thank you Doc T for your quick response. Today is the first day of just water, salt and alfalfa hay. This will give me 14 days to find the SBM. I am also going to try other types of hay if I see that she does not eat today. As for the rice bran I purchased, it is Max-E-Glo Stabilized Bran, I hate to waste it, so could I add it to feed for my senior horses?

        1. I understand the concept of money spent already and that you don’t want to just throw it out. Think about it this way. The rice companies didn’t want to just trow out this byproduct. They wanted to make money from it so they decided to sell it and found a buyer for it. They dressed it up as being good for horses and you believed them so you spent your cash on it.

          In reality, your feeling of not wanting to waste something you bought is in reality anger that you were a buyer of something that doesn’t help your horse but only the bottom line of a company you really don’t have a vested interest in. Unless you own stock in the rice company.

          But you do have a vested interest in your horse. Adding in an inflammatory ingredient where the perceived help to your horse is only marketing lingo is not helping your horse. You are angry that you were “Tom Sawyer’ed” into purchasing the right to throw out somebody else’s garbage.

          It really is a decision between helping your horses now or later after you feed the rice bran.

          1. I found the soybean meal and today is the first day I will be starting to add to feed schedule. After 10 days on hay, salt and water my yearling is much calmer and he overall body composition is noticeably improved. No bloat, coat is shiny and she is much calmer. I searched the internet for the proper time to soak the pellets and SBM and it varies from 30 minutes to overnight. I am soaking both together for 30 minutes to see how that goes. Any recommendations are helpful. Thank you.

          2. Soaking soybean meal (SBM) is not needed nor do I recommend it. Just feed it as is – even out of your hand. If you want you can add some moisture to hay pellets and add the SBM but why soak them? SBM is not soluble in water and I know of no other hog, cattle or chicken farmer soaking it. And in my 50 years of using SBM I have never soaked SBM nor have I heard of horse owners soaking it. In fact, you are the first person asking me about soaking. To think there are searches on the internet suggesting it is radical for me.

            I am really grateful to you for trying this approach to feeding your horses this way and finding out how quickly they have improved. You will be pleased with the addition of SBM. I am just curious where you thought you needed to soak the SBM – where did this come from as I don’t think I ever mentioned that. LMK and I’ll clarify my words in the blog – Doc T

      2. Doc T – I know its been less than 24 hours but I had to put a shout out about how quickly my Miss Bella’s attitude has changed and she is already showing signs of less anxiety. This morning she is eating the alfalfa hay with no hesitation. It can only get better from here. I look forward to the continued success over the next 14 days. Thank you.

  2. My horses are on SBM and no grain diet since February. The results are amazing both shiny coat/hoof and behaviour! I’m considering now to limitate the hay (they have it ad libitum at the moment). The pasture is limited because they don’t want to stay out during the day due to the biting flies. My question is should I put on SBM a 4 years old too? He has a very big hay belly… I think I have read somewhere here that young horses cannot have protein deficiency? Am I wrong?

    1. When do horses become protein deficient? I’m not sure because of several factors. The first is based on what they are being fed. If fed a high sugar diet then they will become protein at an early age. If fed only 1 or 2 types of grass (pasture or hay) then they will become protein deficient a bit later though I’m not sure when. If they are exercised heavily at a young age (raced) then it will occur earlier.

      Protein deficiency is insidious. In addition when there is a good layer of body fat then the muscle loss will be noticed less. As a rule of thumb, I look at protein loss in intervals of 6 years. I base this on the fact that all muscles in humans are regenerated every 6 years. It is an assumption because both humans and horses regenerate their livers in about 4 weeks so I will assume they regenerate their muscles at the same rate of 6 years.

      Looking at race horses, most are fed a lot of grain and are worked hard through intense conditioning. Most race horses break down by 6 years of age if not before. Rarely do they remain sound beyond 6 years.

      The next group are the working show horses who seem to break down around 12 years (between 10 and 14 years). This is when most lameness exams occur from hooves to back bones. It is where most horses are given therapy as well (treatments, medicines and supplements).

      At 18 years most horses are retired from work. At 24 years they are showing protein loss in a poor top line and by 30 years and 36 years there is severe muscle loss along the top line and the cheek muscles.

      My answer then is that most horses fed without a high quality protein source (wild fields with migration between seasonal plants or soybean meal) or are conditioned hard throughout their working life or both will need to start supplementing with extra protein as soon as 2 years of age PLUS their sugar intake restricted. With increasing age and with increasing signs of inflammation (body fat), the importance of adding high quality protein AND reducing insulin spiking foods needs to be addressed carefully. It is therefore much easier to prevent laminitis, equine metabolic syndrome and other nutritionally related diseases than to treat them. SBM is inexpensive, abundant and safe. Better to start early before problems than it is to catch up later.

      1. Thank you very much Dr.T! Your answer is very exhaustive and very helpul. It’s a pleasure to interact with your knowledge and your sense. I’m more than happy to go through SBM with my youngsters too. I’m glad I have finally found such a rewarding way to feed my horses.

  3. Just wondering if there is life in the old timers saying that laminitis/founder ponies should be fed straw (ie: Fibre source but low nutrition)?

    Also to add, I’ve converted to non-grain diets. SBM features for all – even the in work racehorses. And the difference is amazing. Having had a pony drop with acute Laminitis last year (she broke into hay paddock with lots of clover) and was down for 6 weeks, its become a forefront issue for me. Being a barefoot trimmer I’ve found a lot of ‘at risk’ ponies have thrush which I assume means more stress on toe of hoof to avoid the sore frog – then the clover was the last straw that broke the camels back.
    Welsh mare was up and placing at National level show 5 months later – a real miracle.

    1. Thanks for this testimonial! High quality protein is so essential for all horses especially those who are deficient from lack of it in the diet and/or they are consuming it due to the increased sugar in their diet (grain).

      Straw is the “hay” made from wheat, rye, oats and other grains after the grain has been removed. There is usually less starch in straw but you cannot assume that. When horses are bedded on oat straw they tend to eat it because, I assume, it was sweet.

  4. My horses have been on the SBM diet for a year now. I have a 28 year old that can’t eat hay so I have him on pasture all the time. My mare and her yearling are with the MFT that has IR all the time. That means they are in the dry lot with only hay from 8pm to 2pm. I now know that I have been feeding them all way too much hay – mainly because they are not allowed to graze much. The MFT had laminitis in all four feet, but has made a great recovery and is ready to ride again. I’m scared to death to go through this again or create a problem for the other two.
    My question is, would it be better the have them all out on pasture overnight and confined during the day with limited hay? The MFT is on a Green Guard muzzle when I turn him out and he comes in acting like he’s starved. He is a true eating machine. I am also concerned as to how to limit the amount of hay to each horse when they all eat together in the paddock. They are not stalled or separated, so keeping track of how much hay each eats is not possible.
    I was glad to hear that keeping with the 1# of SBM was suggested. I was wondering after a year is this should be deceased or not.I was just getting comfortable with how I was feeding and this blog has me in knots again.

    1. Sorry to have caused you more “knots!” I need to assume that “MTF” is a breed of horse. IR means insulin resistance. Just clarifying for all the readers.

      Horses only on hay and/or pasture require the added essential amino acids found in the soybean meal (SBM) and not in the mono-grass (my way of saying 1 or 2 types) of their forage.

      To answer your question, all you need to do is understand that pasture and hay both have starch. Starch is a very long chain of glucose molecules which is the primary sugar that fuels the cells. It is a poor fuel, like using the cheapest gas you can find for your expensive race car. the cells need a rest from getting this fuel in excess of their daily needs (in other words, exercised horses need more glucose to restore muscle glycogen). Anything in excess will be stored as body fat but more importantly, the cells will become exhausted. This will lead the body to consume their own protein INCLUDING any protein fed to them. This is why some horses actually gain weight on SBM rather than lose body fat while curbing hunger.

      Changing behavior in humans is difficult. We all feel that not feeding a horse hay while they are appearing hungry is cruel. But having horses with metabolic issues including IR is avoidable if we change our habits. Limiting hay and going hungry when the season calls for it (winter dormancy) actually is allowing the rhythm of life to occur. Feeding hay either in addition to pasture (summer) or in excess when there is no pasture only worsen their conditions at the cellular level.

      Feeding horses last summer’s grass (what we all call hay) is a balancing act. You need to use your eyes and not your emotions. You also need to feed adequate high quality protein (SBM) to help satiate the appetite. 1 pound SBM per 1200 pound horse per day is minimum and can go higher in horses being worked. But caution in increasing SBM is recommended until the horse starts to lose body fat. This is when the horse will not convert the extra protein in the feed to sugar but rather use it to restore the amino acid supply.

          1. Sorry about that. MFT is Missouri Fox Trotter. There are so many horsey FB pages and they all abbreviate the breed to keep things short. Took me awhile to learn all the letters.
            While I am here, I have been told over an over that once a horse has had laminitis he can never graze again. I have taken the chance to let him out with the others a couple of hours a day with a muzzle and he is doing fine. If hay and grass are both starch, is it just the sugar in grass? We have lush pastures of fescue and clover. The horses are fed SBM and alfalfa pellets at 8:00pm, then held in the dry lot with limited hay. They are fed SBM an alfalfa pellets again at 8:00am, then they get to go out to the pasture about 1:00pmThey do have access to hay during the day in the dry lot. Most of the night they have nothing to eat. Is this a suitable way of dealing with this. I have decided that the laminitic is doing better when he is with the others and a muzzle. Otherwise he is knocking down fences and not moving much otherwise. Constantly concerned that they are doing okay.

          2. Once a horse has had laminitis, the connection between the hoof and the tissues under the hoof are permanently damaged. It’s like damage to your finger nail where the injury can be seen as a defect in the growth of new nail for years or forever. But over time and with accurate nutrition, I believe the repair can occur.

            The problem is that horses with laminitis are commonly restricted from the cause which is sugar in the form of starch and fructans. This will improve their underlying insulin resistance but it will not repair the damaged hoof structure. It seems rare that these injured horses are told to improve their nutrition by feeding more of the missing amino acids lacking in their diet. They are only told the reason behind sugar restriction which is to reduce insulin resistance but this only goes so far and often gives poor results.

            The other reason to restrict food intake is hormesis as explained in this blog. But let’s look at something a bit more concrete – the insulin to glucagon ratio. Insulin is the hormone that makes body fat and glucagon is the hormone that consumes body fat.

            In humans, ketosis seems to be the rage for fat loss but for many people it doesn’t work. The reason for this is actually been tested and it comes down to this. The goal of a fat reduction diet is to decrease insulin and increase glucagon. These 2 opposing hormones regulate whether fat is added to the body or is consumed by the body. It is called the insulin-glucagon ratio (I:G).

            In the standard American diet (fast food) the I:G ratio is very high because we consume so much sugar which causes insulin to be high. As long as sugar is available, insulin will remain high and glucagon low with a ratio from 4 (without added protein) to 70 (with added protein). When we restrict the sugar intake to 50g per day or less, the I:G ratio gets down to about 1.3 which will cause fat loss. Fasting (in humans) will lower it to 0.8 further adding to fat loss. But, when protein is added to the carb restricted diet of 50g per day, the I:G ratio remains at 1.3 AND the muscle is maintained or increases.

            To repeat and clarify the above information, adding protein while keeping the high sugar intake in humans actually increases insulin which causes more inflammation and makes things worse. In horses with laminitis you need to restrict glucose intake while adding soybean meal (SBM) until the body normalizes (body fat is normal, blood insulin levels are normal). This may take a year or more to occur and during this time the hoof connection can repair.

            I think the best approach to laminitis recovery is to monitor the blood insulin levels as well as observe the body condition score with the aim of getting a BCS of 5. Both of these can be with the help of your veterinarian. Also monitor the quality of the hooves with the help of your farrier and vet. There is no “correct” way to do this but if you get the I:G ratio correct and you provide enough high quality protein, I believe that many horses will no longer suffer from recurring bouts of laminitis and many more will never experience it.

            Please document everything you do so we can all learn from your experience.

  5. Wow…this is a whole new avenue for thought. First I believed grass hay was the way to go with my mare that has some front hoof issues. Alfalfa was for working horse or to fatten up cows. Net feeding 24/7 made sense to help buffer the gastric acid in the stomach and have her eat more like grazing. The big difference she doesn’t move much in her stall as she would in pasture. She does gain weight on the net , she is a eating machine. She has been net feeding for approximately 3 years. In the last year, she developed fat bubbles above her eyes, fat pads at her shoulders, and a bit of cresty neck. She looked pregnant. I knew something wasn’t right. Farrier noticed the eyes. Saw a vet at shot time and she recommended magnesium oxide to help metabolize her carbs. So the journey begins with supplements. Everyone has a suggestion, Have been going the herbal route, haven’t blood tested yet. I did know that she had to loose some weight so cut her hay back but still on the net. Didn’t want her to go without hay for any periods of time. She did start to loose her bubbles above the eyes, and her belly. Her coat this year is different, not shedding off completely. My gut is telling me this is not working, it’s obvious. So the reason I’m writing this long story is because it’s so easy to be influenced by all the information of companies wanting to sell there products, because we want to do right for our horse. After reading alot of the articles by Dr. T what he saying makes sense to me. I believe she is protein deficient and its starting to show. I hope it’s not to late, she’s going on the 10 day diet then the SBM and alfalfa, hay water and salt. After that I explore the topic also in this blog about hormesis. Thank you Dr. Tucker

    1. Thank you Vivian for this full description of what your horse is going through. So many others will relate to this so I was to address something you said for the rest of the readers as well as you (but you “get it”).

      The Protein Leverage Hypotheses” states that humans will eat until their protein levels are met. In other words, we eat not because we are needing fuel but because we are lacking building materials to sustain life. The result is that we continue to intake low protein food with high calories PLUS we start to digest our own proteins because our cells are becoming exhausted from the sugar load. The result is 1) loss of muscle as seen in the geriatric population with a high incidence of falls, 2) the development of metabolic syndrome (diabetes, insulin resistance, fatty liver, high blood triglycerides) and 3) obesity. Remember this: as long as there is sugar in excess in our diet there will be insulin AND as long as there is insulin there will be NO LOSS of body fat. Adding adequate amounts of HIGH QUALITY protein (all the essential amino acids) will reduce our desire to eat more foods low in protein and high in carbohydrates.

      Now re-read the above paragraph and replace the word “humans” with “horses.” My theory is that all mammals work this way. Removing the inflammatory ingredients, reducing the starch, allowing for hormesis and supplying all the essential amino acids should allow for the return of horses to a better metabolic state with reduction of body fat and the restoration of health. We all are waiting with excitement for your updates. Don’t forget us!

      1. Thank you for your reply, I was also relating your information to my ex who was a diabetic. It was much better when he ate more protein and good fats, which helped his sugar levels to remain more level. She is on the 10 day now and I will post after that. I thought she was grain free untill I read your info on flax seed. I swear she already looks better after a few days. Vivisn & Maisy.

      2. Vivians story is my mares to a tee. I am so glad I found this site, because, like Vivian, my gut was telling me what I wAs doing to get my horse healthy was wrong. I’m starting the 10 day diet now, cutting out all “supplements” and finding soybean meal. My mare has a horrible hay belly that will not go away and she has stopped sweating. My fingers are crossed that I have found the answer to my dilemma.

  6. I have to comment on the feeding of hay. (The hard part for horse owners) At least in northern Minnesota, feeding horses hay in the winter has always been done, and is not something new in the last 60 years. I got my first horse in ’58. Baled hay was already a staple in the winter. Many, if not most farmers had tractors and balers by then. The early settlers, (early 1900’s always gave hay to the horses in the winter along with the cattle). The horses were mainly used then in logging in the winter and plowing in the summer and hay was a staple. You couldn’t have horses or cattle here without available hay as a staple and you still can’t. Snow is too deep; winters are brutal. In a bad year, the deer and moose will eat the bark off the trees, but horses don’t survive this way. So, to say that feeding hay is a fairly new idea (last 60 years) is not correct. What do you think people on the farms did with their horses over the winter? They didn’t turn them loose to fend for themselves. They fed them hay.
    (correct me if I misunderstood something)

    1. Hello again Judy. Please see my reply to your other comment as I address these concepts there.

      Let’s look at the word “new” in context to what I am saying. Tractors did become popular after World War II and certainly after the Korean War as industry turned away from armament and towards our economy. The interstate system of roads began and Mack trucks were becoming more popular. Feed stores with delivery to farms sprang up too. Before this most people with horses also had land with pasture which were used to produce hay, usually by horse drawn machines and harvested with manual labor.

      But we need to look a little further back when there were no fences. Horses migrated to where they could survive. Anyone putting horses, cattle, pets or themselves into a winter situation where food was not available needed to store food in some form. They also learned to marshall these supplies which led everyone to stress their bodies which resulted in loss of body fat PLUS cellular hormesis. This was important because this period of food deprivation is a common part of life for ALL animals on this planet – and even the plants.

      The point of this article is to bring awareness to horse owners that the continuous automatic feeding of hay throughout the winter is no different than you and me going out to the fast food restaurants and convenient stores every day to eat starch. The result is a population that has human metabolic disease (obesity, high blood triglycerides, fatty liver, insulin resistance and diabetes) and the associated diseases, sarcopenia (muscle loss from gluconeogenesis) and comorbidity factors decreasing our ability to face challenges such as COVID-19. We see the same thing in our horses as well as out pets.

      Hormesis is an ancient process allowing for the health span of animals to be high throughout the lifespan. Factors affecting this include the prevention of migration and the feeding of mono-grass diets throughout the year. We, as horse owners, need to be aware of this and adapt our feeding methods to accurately reflect the ancient needs of our horses. And we can’t do this AND starve our horses. There is a balance we need to find for individual horses with individual needs. Thanks again, Judy, for your “aged” perspective of horse care and helping me to clarify what I was trying to say.

  7. We had -50 here on the thermometer last winter, with in the -40s many days in a row.. Doesn’t a horse need to put on some body fat for the winters in northern Minnesota? All the animals in this area put on weight for the winter. People get bigger appetites, too. I’ve never restricted hay in the winter. In severe winters, a horse will lose weight, and I didn’t think this was a good thing during extreme cold because they need body fat to keep warm..

    1. Judy – hay is needed for horses to survive adverse conditions. They would usually migrate to avoid these extreme temperatures as there would be no available forage in the cold and under snow. But when they are prevented from migrating then the owners are responsible to add the food needed to survive.

      The point though is that owners just feed the hay without the thought of what the horse is needing with the result that most horses are over fed hay. What this means is that they intake glucose (in the form of starch) in excess of their needs. As long as there is glucose there is insulin. This prevents the use of body fat as fuel as well as hormesis to allow for the return to health of the cells. The horses are kept on hay into the warmer weather and the pastures add their supply of starch. The horse never gets “time off” from processing glucose and this, over years, leads to the loss of body protein. That, in turns, is the root cause of the breakdowns and illnesses we start to see in horses 12 years old and older.

      The goal of all horse owners is to manage each individual horse so that they do not receive excess glucose throughout the winter when their bodies are seeking some down time to restore cellular health. The clear indicator of this is the loss of body fat. But never should this be allowed to become life threatening.

      One of the best ways to regulate the intake of excess glucose / starch is to feed large amounts of HIGH QUALITY protein (protein with ALL the essential amino acids). This will limit the excess intake of starch as the horses receiving enough protein will become satiated. This is the basis of the “Protein Leverage Hypothesis” established in many animals including humans. This can be done by feeding at least 1 pound of soybean meal per day per 1200 pound horse. See my protein articles.

      We all here would love to hear your observations next spring especially with any horse with obesity, metabolic syndrome, Cushing’s and insulin resistance. I suggest you start a journal for each horse as age, use, breed and individual genetics all play a role in determining how much hay to feed as the winter progresses. It is time we stopped our automated way of feeding the horses for convenience and started feeding them individually and with understanding of the principles. Thanks for your comment.

      1. After a year of being on the 1lb a day of SBM and the horse is looking good, i thought it was ok to either cut down on the SBM or cut it out entirely…..and continue to feed good quality forage….is this right?

        1. I used to recommend that but now, with some more information, I do not recommend removing SBM from a horse’s diet for most horses. This is based on most horses being fed a mono-grass pasture and mono grass hay (or 2 but still limited in protein sources). In addition most horses are being fed excess glucose throughout the year as noted in this blog. As long as amino acids are being consumed through excess glucose intake (mitochondria exhaustion) and high quality proteins are not in the feed (all farmed pasture and hay are only “good quality”, horses should continue being fed SBM for the rest of their lives. Luckily it is inexpensive, abundant and well liked by horses. Thanks Shelly, Doc T

  8. I am frankly confused by this article. If hay is last summer’s grass, and letting horses forage on pasture is healthier for them, then why restrict hay? Both pasture grass and hay have starch, correct?

    I really need to know how to function on a property with very limited pasture. Both my horses–a mini shetland and a Rocky–improved greatly in body condition on ad lib hay and 24 hr turnout in years past. But this past year, their first year on SBM, both got scary fat on ad lib hay AND SBM. So is the piece I’m missing that with SBM fed daily they no longer need ad lib hay?

    I was forced to weigh the mini’s hay and start feeding it to him only 2x a day in a small hole hay net because he became frightfully fat. But what finally caused both of them to lose weight and lose hay bellies was taking them out in the wilderness for five days where they had only wild grass to eat and they were in work. We just got home and they both look great.

    Right now they are on a hilly track at my home, with access only to sparse native grass, and I’m feeding little to no hay and letting them graze the track down. I do have two small pastures with tall grass with seed heads I could also turn them out on for a couple of hours a day. What do I do when the track is bare, as it will be shortly? I don’t want the small pastures stripped, and they aren’t set up for 24 hr use.

    And what do I do about buying hay this year? The two of them went through 6 tons of ad lib straight grass hay fed in 1″ hay nets this past year. Should I feed much less? How should I feed during subzero Montana winters? They have stalls to escape the wind, and heated water and 24 hr turnout. How do I keep them from getting fat again over the winter when there is no work for them? Is it time to quit the SBM?

    I want my horses to keep a nice BCS of about 4-5, no more. This past winter they may have gotten as bad as a 7 or 8. The Rocky is age 11, 1100 lbs, 15H. The mini shetland is 42″, age 14, and I would guess about 400 lbs.

    Thanks in advance for any further decomplexicating you can offer.

    1. It is confusing because of what we have been taught ingrained in our minds. then I come along and say what I say and you realize that what you are doing isn’t working. Then you do something else like pasture in the woods and instantly see an improvement. Then the fat returns and is accentuated with the addition of SBM. Wow – enough to spin there head right off the shoulders!

      The ad lib hay is feeding glucose in excess of their metabolic needs every day and that is what this blog is about. The horses continue to gain fat but underlying the fat gain is muscle loss. The cells are not going through hormesis and the mitochondria are exhausted. Because of this the brain signals for auto conversion of protein (amino acids) into more glucose! (see my other blogs or enroll in my nutrition course if you don’t understand this).

      The result of horses converting protein to sugar is that many if not all horses will actually convert the protein fed directly into more glucose. This is the reason some horses get fat with SBM. These horses need to reduce their glucose intake and get back to normal metabolism which requires up to 6 weeks on a no grain diet and reduction in hay plus pasture consumption.

      If pasture is limited then hay needs to be fed. Unfortunately most hay is of one or two types of grasses or a grass plus a legume. These are poor quality protein sources. Worse, many grass seeds have been developed to increase starch production in cattle so they are not the same grasses found in the past or in uncultivated woods. This is why they did so well in very little time. Their microbiota probably also benefited from the diversity found in the wild pasture. After all, we are really feeding the microbes and they, in turn, are feeding us.

      You are correct that this blog is the missing piece – that you need to reduce the hay consumption. They are not self regulating and are over eating into obesity because, 1) The mono-grass hay is developed to have more sugar than wild grass, 2) the glucose intake is continuous causing metabolic syndrome, added body fat and mitochondrial exhaustion with protein loss and 3) the addition of protein as SBM is being converted into glucose before it even enters the body from the digestive track.

      Your goal is to feed the hay in amounts that meet but does not exceed their daily needs. This will be different for each horse and makes having a mini and a horse together difficult. They will maintain their condition without fat gain if you are careful through the summer. Feed no grain, treats or supplements as their microbiota adjusts. Consider revisiting the wild grasses occasionally this summer. Add in the SBM as you notice them stabilize with a little at first and increasing slowly adjusting the hay as you go to maintain their weight. The SBM will help satisfy their hunger. As winter comes along don’t increase their hay unless needed for severe weather. They should lose their fat and go through hormesis so by April they should look and feel very healthy.

    1. All horses need forage to survive. Their intake serves two purposes. The first is to supply fuel for metabolism and to restore the glycogen reserves of glucose. The second is to add body fast for the upcoming winter when food with glucose becomes scarce.

      We now have an ever present source of glucose (starch) in bales of last summer’s grass. In humans we have pantries and refrigerators filled with food and replenishment services that deliver to our door more food. Hay is no different for horses with feed dealers ready to replenish our hay mow with just a phone call and a credit card.

      You need to determine how much hay is needed for an individual horse based on their age, breed, use and any illnesses they have. Then you need to feed the amount of hay needed to maintain their body condition if it is perfect, add more if they need more or reduce it if they need fat loss. There is no test or formula. Just understanding that hay is not a normal feed and that by overfeeding hay throughout the year we are not allowing horses to go through the normal ebb and flow of life. This prevents hormesis which leads to mitochondrial exhaustion, protein loss, etc (see my blogs).

      Some people have reported that their horses only get what is in the pasture all winter with fat loss by spring time. They also say that the horses at that time also look sleek, shiny and healthy with full energy. This is because they have gone through the process of maintenance and repair. Losing fat is not bad but is actually an indicator that cellular health is being restored. Like anyone on vacation finding energy to get back into the game.

      Feed your horses with a new keen eye. It is not a cookie recipe of all, some or nothing. It is a day by day adjustment. Things might look good the beginning of January but then a winter storm come in with an Arctic blast. Your horse will need shelter and MORE HAY! After this though you might reduce the hay and watch carefully the fat covering, the hair coat fullness, the overall health and shine in the eye and determine that all is good with the reduced hay diet. Day by day, spring will come again and the grass will fatten them up again. At that point you do not need to feed hay and they may not even want hay.

      Remember if there are signs of protein loss (poor top line, poor hair coat, poor hooves, hay belly) then add a high quality protein to restore all the missing amino acids. This will really help the horses through the winter months because they will not show signs they are looking for a missing ingredient. This is often confused with hunger.

  9. Update….had xrays done and 6 & 7 degree rotation on front hooves and 4 & 5 rotation on backs….started the DMSO drip today along with 4 grams bute dailey and two 1ml injection of a acepromazine twice dailey….The vet made custom tennis shoes for her…thinks this has been a long time coming…..said we can recoup but will always need a muzzle to graze when that is allowed somedsy….for now, she lives in the barn with hay, water and SBM and her salt until she is sound again

    1. Thank you for this update Shelly. Please continue to come back here with updates that will be of interest to all. I am sure everyone here is praying for a full recovery. With your attention and efforts – and patience – I’m sure she will do well. Doc T

      1. Still no real response, meaning hardly walking….my vet even made her some custom tennis shoes which helps her to move some….she is still taking all the pain meds he perscribed along with ulser medicine and acepromazine for blood flow….he said its a long road ahead , maybe even a year to recover but when and if that day comes, she will always need a muzzle and only at night for grazing….she also has thin soles, which i didnt know since shes always been barefoot and never gimpy….she’s my husband’s horse and we both feel her quality of life is gone….with the meds, prone to founder again, muzzle , special soft boots and being stuck in the barn all day, and the possibility of having naviculer ,IR and Metabolic syndrome, he has decided to put her down….this founder has come out of the blue with no prior hoof problems other then a couple abscesses….one day she’s running around, next day she cant walk ….its so heartbreaking to see her this way and in pain…The vet said this has been going on for awhile but we never saw any indications ….meanwhile her buddy, my QH gelding is fine and grazing …I just dont get it

        1. Just to let all know, the pony, the subject of this blog, became worse, was suffering and was euthanized today.

          All who read this blog will be sharing your loss with you and your husband. The decision to end her life is something many of us have had the solemn duty as owners to do. It is a long lasting sadness I, for one, have experienced too many times.

          The sudden turn from running in the field to being too painful to walk is made worse by the news that this has been going on for a while. Questions arise wondering why the vet or farrier or anyone didn’t let you know this was a possibility some time ago. And why this horse and not your other horse or any other horse you see down your road?

          From reading this blog you can see there is a complicated process that has been developed over a million years to help our horses survive in an unforgiving world. Genes mutate because of signaling from the environment, from viruses that constantly insert “software updates” into the genetic code and by ordinary copying mistakes from incessant doubling and dividing of cellular material in reproducing cells. We assume perfection in an industrial world that offer guarantees and warranties but life is not a machine.

          You may never get a full explanation or a full understanding. However this blog will undoubtedly help others who read it and take the time to change their way of feeding their horses before the hooves start the breakdown yours and so many other horses have gone through. In 1979 I was in the halls of the vet school at Cornell. I was still an undergraduate but I discovered that every Friday afternoon at 4:30, rounds would be help in the post mortem room. I would sneak in and sit among the vet students. Livers, lungs, hearts and skulls lay on the stainless steel tables and the professor, Dr King, described the lesions that killed the animal. On occasion he would have displayed the hooves of horses that had died from laminitis. After a while he began to recognize me and even though he was feared by students who he picked on unmercifully, he never called on me. He looked at me but always passed on the opportunity because I was not a vet student – yet. After rounds one day I mustered the courage to say something to this powerful and world renowned veterinary pathologist.

          “Dr King,” I blurted out in the hallway and he turned around and pierced me with his eyes. I trembled then blurted out, “I plan to figure out why horses founder.” It was only a seed of conviction at the time but after seeing the cut open hooves that afternoon from a pony that had succumbed to it and from experiencing several horses in my life suffer from it, I knew that there must be an answer.

          But I am not a researcher and in 41 years, it seems that few still understand this dreaded condition of horses. As a student I saw the first cases ever recorded of horses (not ponies) coming down with laminitis overnight after bedding on black walnut shavings. About 10 years ago a philanthropic owner down here in Florida funded the biennial laminitis conference and I learned about sugar overload and insulin resistance behind all laminitis cases. But no one could give the molecular or cellular reason for the event. They could easily cause it with both carbohydrate overload and with black walnut shavings and most laminitis studies are initiates with the carbohydrate model.

          This blog has attempted to dig into the cellular reason for laminitis but connecting this to changes in the grass is still needed. The variety of grass available for pasture, I believe, has been genetically altered by seed companies to promote growth in grazing animals used for food such as cattle. The increased starch or possibly the fructans created by grasses exceed the dietary needs of many horses which starts the cascade of events I describe here. Fructan are chains of fructose in plants that help to resist freezing temperatures. Fructans are considered in humans to be a resistant starch that promote the health of the hind gut bacteria but I am not sure of their effects in horses. Whatever the molecular reason is behind laminitis occurring in grasses, there are many horses susceptible to it. It seems unfair that the genetic manipulation through controlled breeding of plants has made beautiful looking pastures deadly for some horses.

          Our condolences to you and your husband. My hope is that someone with research savvy will also read this and help us learn why her suffering occurred. Ending laminitis is still something I want to achieve. Thank you for reaching out with your question a while ago that created this blog. I am sorry we, as veterinarians, still cannot prevent founder from occurring.

  10. Your call to not not feed hay 24 hrs a day rings true with our experience. I know many feed with slow-feet nets, but we have not done that, and our horses go for at least several hours at night with no hay. In the summer, they get mostly just pasture, and in winter we plant a small amount of rye for something green to nibble on, plus hay. This past winter, I fed less hay than normal, sort of an experiment, and they looked great all winter. We occasionally feed a supplement (you’ve been so helpful in your blog with helping us sort this out). Our horses are shiny and happy. It will be so interesting to follow future research on this. The interpretation of research results is a tricky art, and we need to be flexible in our beliefs over time. And thank you for reminding us that hay in bales is a relatively new reality. Lots to think about here. Thank you for sharing your thoughts and experience!

    1. Thanks for this input. You are helping horse owners reading this to understand the concepts here.

      This blog is full of science and will take several readings to understand it. I read and re-read my notes to write it. It is all relatively new but the way you told us of your experience will help many understand it even if they can’t remember “aldose reductase.”

      Gratefully, Doc T

  11. I’m confused by what you wrote. Maybe because of the lack of data to back it up (of course there’s very little funding for equine research). In the north we have no pasture in the winter and in the South we have pasture most of the year. Are you proposing to starve the northern horses by keeping them off hay and grain/fiber all winter, and pulling the Southern horses off pasture in the winter? Wouldn’t this only work for really FAT horses? Wouldn’t the resulting constant ketosis stress their kidneys?

    1. You are close. It is not just ketosis as most horses today will continue to be fed especially if winter is severe. The concept here is that the continuous intake of glucose ABOVE their metabolic needs and their need to restore glycogen is still signaling that winter is coming. This leads to more body fat as well as the further development of metabolic syndrome including obesity, insulin resistance, mitochondrial exhaustion and protein loss. It is insidious and at a future point we start to see disease and lameness develop.

      Horse owners need to develop an eye to look for the balance between enough food and too much food. Most look at their water and say, “It’s time to feed the horses.” Little thought is used to avoid this cookie cutter approach to their health. Instead, owners need to look at each individual and adjust their feeding to the age, breed, use, season and any genetic disorder or illness they have. The goal is to determine how much food is needed to replace the lost glycogen.

      With the understanding of how the cells and proteins / enzymes work with the bacteria to convert raw food into fuel and then into either energy or to fuel storage, any horse owner will be able to feed any horse. I often ask how to feed an Arabian, an Icelandic horse and a Mongolian horse all living in Mississippi. The answer is differently but using the same principles of digestion. This blog shows another layer of overlooked fundamentals I touched on a while back in a blog called “Carbohydrate Dependency.” This has more detail but all animals in our domestic world (including humans) are now more unhealthy. With the COVID pandemic it has become obvious to those looking that it is not the virus but the underlying health issues that is causing illness and death. The worst co-morbidity issue is obesity, or as I read today, “Diabesity.” Stopping insulin resistance will thwart COVID as well as laminitis and other diseases of horses and humans.

      My apology for confusing you. While the principle here is simple, most horse owners just want to know what to do. My wife tells me this all the time. So here I’ll do my best. Feed your horses no inflammatory ingredients and limit their forage to the point you see them lose body fat. Then, depending on your goals, adjust what they eat to maintain your goal. For example if they are fat and retired then have them lose a lot of fat over the winter and allow them to spring back in the summer. But if they are competing, their fuel needs will be more so feed them to maintain their condition. Here they will consume their free glucose or they will store it as glycogen. Just don’t give them enough to add body fat because athletes usually have little body fat.

      Remember to restore their lost amino acids. You can’t do a blood test for this but look for a poor top line, a poor hair coat, poor condition of the hooves and the presence of a hay belly. All of these are signs of chronic protein deficiency. Adding this to their diet will help to satiate them as food becomes scarce. (see my blogs on protein)

  12. In the ECIR group, it is thought, if your horse has PPID, pasture, fresh grass, is not to be taken in. Two horses here tested positive, ECIR. One tolerated Prascend, the other did not, at all. Severe GI disturbances that did not go away even at 1/4 dosing after pulling him off of it for a week. I asked the group about the intermittent fasting I do to promote autophagy and regeneration for the horses. It was a clear NO as feed back, as I was told that would promote ulcers. The idea of free choice hay and the horse will self regulate eventually came up. The Arab on Prascend has lost all fat pads acquired in his 22 years of life, and the other horse, a large WB, age 21, has too, but is only on CBDs, 100% organic hemp, at a increased dose. (TRH respectively was 1000 and 600) Both horses have shed out this year. They do get turned out for 30′ with the other two, and there is a lot of running around. The WB is still being ridden. I still am concerned about inflammation though, and the idea of leaving them on pasture goes against all other data coming thru the ECIR group. You seem to be recommending no hay. We feed Timothy and measure it out for each feeding. 14lbs/day for the small Arab, and 17lbs/day for the 1200 lb WB. I am already in violation of the Rx with the turnout, but it is so social, and seems to be a ok on the hooves. More than that and I do see changes. Please advise. Thank you!!

    1. I did not say that pasture would be OK for horses with IR or Cushing’s or laminitis or any other condition where adding the starch of pasture would worsen their condition. What I did ask was why are we feeding last summer’s grass all year long or this summers hay while there is summer pasture? If hay is fed in the winter then the period where a horse would decrease their starch intake would be lost. This would prevent hormesis as well as promote the signaling that winter is still coming. This would lead to additional development of metabolic syndrome which includes IR as well as mitochondrial exhaustion causing chronic protein deficiency.

      Please read my reply to another comment on this blog about ulcers in the digestive tract of horses. Horses will not “self regulate” food intake if they are missing something in their diet. That “thing” they are missing apparently is protein as horses fed adequate amounts of all of the essential amino acids eliminate their food aggression.

      My belief is that Cushing’s disease is a neurodegenerative disease prevented by avoiding the loss of the proteins needed to prevent the neurodegeneration in the brain. Prascend is a replacement of the dopamine neurotransmitter (a protein). While the actual cause is still unknown, many horse owners, with the help of testing through their veterinarian, have been able to normalize the horse’s cortisol without medication by removing inflammatory foods and replacing the lost amino acids.

      There is abundant evidence that metabolic syndrome in humans and other lab mammals tested (and there I am assuming horses too) is secondary to the continuous feeding of glucose with the conversion of glucose into fructose. Looking at the feeding practices in today’s horses I also see the continuous feeding of glucose not just in grains but in the abundant amount of hay fed. I wanted to draw attention to when hay was first made available to horse owners. It was fed only in the winter when they needed it.

      Please don’t confuse my thought of NOT feeding hay when pasture is available to preferring pasture over hay for all horses. This will be ill advised for most horses especially if it is a novel idea. My point is really this. Our horses need glucose to replenish the glycogen stores used throughout the day as well as fuel the metabolic processes in every moment of life. However the purpose of storing fuel for winter in the form of body and liver fat is necessary when there is no other food available to eat. While horses did migrate, the grasses still went through a dormancy period everywhere they lived. This period of scarcity was a welcomed period in cellular health when the cells could do their maintenance.

      For horses in the northern hemisphere, it is the middle of summer with winter 6 months away. Horses with EC and IR need to be cautious now as they tread lightly through summer pasture and abundant fresh hay. But I can see no downside to limiting these now to maintain their weight then continue to restrict through the winter to kick in hormesis and body fat reduction. Those of you in the Southern Hemisphere are in mid winter where restricting access to hay and providing limited turn out of dormant grass will encourage fat loss. Adding a protein source such as soybean meal will help to satiate them reducing their desire to eat which in turn will rest the digestive system and allow the cells to use ketone bodies for fuel.

      Owners who have limited the intake of food in their horses to just winter pasture through the winter have reported the loss of body fat and with the addition of SBM they have reported their horses returning to normal health. However it is hard to change from what we do now to something different. The good news is that this costs nothing to do and you can always revert back to the old way of feeding if you become worried. You can also join “The Horse’s Advocate” FB group to hear what others have been through, their concerns and the results they have gotten. It is a safe and free place to exchange information on this.

        1. I look at it as a neuropeptide which is derived from the amino acid tyrosine. Therefore if there is a specific amino acid deficiency then it is reasonable to think that there is no neurotransmitter. Thanks for allowing me to clarify this.

  13. This is great Info. I know I will get the following from clients: “my horse has ulcers and I try to give him free choice hay so that he can keep something in his stomach to buffer the acid”. (This is obviously going to be for those who have horses that are stall kept)

    1. Filling the stomach with hay BEFORE EXERCISE will reduce the splash of stomach acid onto the non-glandular portion of the stomach according to the vet who helped develop Gastro Guard. He said this to us in a small meeting of vets back when Gastro Guard was first introduced. At that point, gastric ulcers were only found in TB race horses.

      Today ulcers can be found anywhere in the digestive tract of horses and humans (small and large intestines as well as the mouth and stomach). It is now well known that the cause of digestive tract ulcers is from a dysbiosis – where the normal microbes of the affected area are no longer healthy or have been replaced with other bacteria not normally found there. Restoring the normal microbiota restores the lining of the gut. Get the bacteria right and the ulcers will be gone.

      Next time someone says, “My horse has ulcers,” ask them if they are talking about gastric, duodenal, colonic, anal, or oral ulcers. That will get their attention. Then tell them it is not feeding hay 24 / 7 but eliminating the inflammatory ingredients including 10 carrots a day or the red mineral salt lick that will heal the ulcers. Or, you can just ignore them and wait for someone willing to listen and change from what is NOT working to something that might help. Anyway, thank you for your help and for your understanding. Doc T

  14. “Other horses may be OK with feeding hay every day…” You got me on this one, Doc T! I always assumed if your horse is overweight that hay would be the proper diet, eliminating feeds and limiting pasture. Am I wrong? Sorry if I missed this point in your article, although I do understand the idea that it’s ok to let the stored fat (clean-up crew) take over periodically.

    1. Remember that hay is last summer’s pasture and depending on how well the process of making that hay, the glucose of starch will still be significantly in it. People for a long time were concerned with the depletion of vitamins in the hay but this is not really a concern relative to the starch (non structural carbohydrate or NSC). If you have a fat horse and you feed starch in any form day after day throughout the year, the horse will never lose the body fat.

      We have been hearing more and more in nutrition of ALL species that the food eaten should be only food that can be found in the environment at the time of consuming it. For example, in humans it is becoming common not to eat fruit or vegetables unless it was harvested that day. Of course this is the way it was before refrigerators and preserving techniques were developed. The same is true for horses.

      It may me more recognizable to think that grains are only available during a short period of the year. We forget that hay not only is last summer’s grass but the fact that we have hay is only a recent technology. “Recent” means that 60 years ago there were no highways, large trucking outfits, tractors, baling machines, hay distributors or feed stores. Most horse owners only had pasture.

      All animals need time off from digestion of food. As the cells no longer are being fed glucose from the starch intake for the fuel, they become “stressed” forcing the body to switch over to an alternate fuel which is the stored fuel in the form of body fat. Remember that both sugar AND fat are made of the same elements – carbon, hydrogen and oxygen. They are put together differently and the body uses different processes to turn these fuels into energy. This ability to use different fuels is called “mitochondrial flexibility.”

      When the cell is being fed a restricted starch intake (when they are forced to use body fat as the fuel) then the cell is running more efficiently. This is when “hormesis” occurs which makes the cell and the overall body healthier.

      The point of this blog is that horses need time away from starch. They are really efficient at digesting cellulose with their hind gut which allows them to survive on low starch / high cellulose dormant pasture. However, when there is abundant starch in their feed every day (grains and hay), the horse doesn’t need the fat formed from cellulose. The excess fuels (both starch and fat) still need to be stored if it isn’t going to be used. The result is that horses develop excess body fat. In addition, the horse goes into survival mode from the excess starch intake by converting the glucose into fructose which 1) causes mitochondrial exhaustion, 2) causes excess amino acid consumption / chronic protein deficiency, 3) creates insulin resistance and 4) creates the signs on EMS or Equine Metabolic Syndrome. All of this is done to survive the upcoming long winter the excess glucose is signaling the body to prepare for.

      Subsequent to all of the long term and never ending metabolic changes is the development of illness (Cushing’s disease, unthriftiness, colic, old age), unsoundness (laminitis, connective tissue disorders), behavioral issues (hyperactivity, poor work ethic, bad behavior) and a loss of money and time invested in the purchase, maintenance and loss of use of a horse not being allowed to eat like a horse.

      We all need to re-think our daily use of hay in feeding horses. Individuals, use of horse and the current season all play a factor and we need to look at our horses with this new and fresh perspective that hay, when used properly and judiciously is good but when just given ad lib may be doing more harm than good.

      1. Doc T, I get all that you are saying. But how to fix it? I have a mare that’s not sweating, is obese even with an hour of exercise a day. She is on native grass pasture (Bahia. Bermuda, weeds, not fertilized). Salt block and water. And she is still fat. And she eats CONSTANTLY! So what do I do?

        1. Where is the protein? She needs a minimum of 0.5g per pound of body weight. Assuming she is 1200 pounds and eats about 20 pounds of forage daily, adding 1 pound SBM daily will meet this minimum. See the protein blogs for details.

          The protein leverage hypothesis (Google this) states that humans, lab animals and I assume horses will eat until their protein needs are met. I now think that horses are NOT “hungry” but instead are seeking out the amino acids that will satiate them. Mini horses and ponies with sufficient high quality protein (SBM) are now grazing without muzzles and sleeping in the hay.

          And I have more! From human and dog research….

          When eating a diet with excessive carbohydrates (starch in horses) beyond their daily needs will keep the amount of insulin high. The purpose of insulin is to add body fat for winter. The opposite hormone to insulin is glucagon with removes body fat to use for fuel during winter. When measuring the amount of insulin to glucagon, the ratio (I:G ratio) is about 4. This keeps the human fat.

          In fasting 24 hours, the I:G ratio falls to 0.8 and the human loses fat but it is not the complete story. To get the fat created from the body into the cell for fuel, carnitine is required and this compound is made from the 2 amino acids lysine and methionine (2 of the 3 “limiting” amino acids found in SBM). This is how the mitochondria use fat for fuel.

          Now here is the interesting part. When humans are fed more sugar than they need (>100g per day) then after adding protein, the I:G ratio rises to 70!!! The result is weight gain and not fat loss.

          What appears to be happening with your constantly eating horse is her consuming too much glucose (carbs) and too little high quality protein (SBM). Limit turn out time or dry lot her and limit the amount of hay PLUS add the SBM until her body gets the I:G ratio correct and she loses fat. Don’t panic when you realize the extent of muscle loss when the fat covering this is seen.

          The goal here is to mimic winter, allow for hormesis and initiate ketosis (using ketone bodies for fuel but not creating keto acidosis). Starvation is NOT the goal but she will think it at first. Once you see fat loss you can gradually allow short turn out time but this will add carbs. Exercise at this point will help consume the extra glucose in her diet. But adding exercise in the first month as she switches to ketone bodies for fuel actually doesn’t help. This is because exercise with the breakdown of muscle tissue is inflammatory.

          A lot to chew on here – maybe a future blog?

    2. What does one do if all they can feed is hay? That’s all we have in S. California. We do not have pastures or grazing that would allow a horse to live on it. So in my case, my IR horse eats teff grass and alfalfa with no grain products. She was managed within normal numbers for over a year but came out of spring with higher than normal with eating the same. I can not test every batch of hay I get, I know it varies but I buy in 10 bale increments. All her regular blood work is fine, no issues there.

      1. Feeding hay has many of the ingredients found in grass so feeding any forage to an IR horse needs to go with caution. It actually takes a lot of effort to look and adjust weekly if not daily.

        You need to look for body fat and asses this with the overall health and attitude of the horse. IR, according to this research, is secondary to he daily feeding of glucose with its conversion into fructose. This sets off the pathway of uric acid production with subsequent inflammation of the pancreas which leads to metabolic syndrome including IR. I also believe fructose metabolism is behind mitochondrial exhaustion with secondary protein loss.

        Therefore even if you have no pasture, if you are feeding hay which provides glucose in excess of your horse’s needs then the excess will trigger the conversion into fructose. While this has not been shown in horses (yet), it has been shown in humans and other lab mammals. For me I have trouble finding another reason for the increase in metabolic syndrome in horses since the addition of grains and hay to our horse’s diets.

        Here is an experiment for you in southern CA where there is no pasture. Limit feeding hay to within an 12 hour window even if this thought makes you cringe. Remember that ulcers are caused by a dysbiosis of the gut microflora and not emptying of the stomach. The exception here is if you exercise your horse after an all night fast and before filling the stomach with hay. Don’t do that!

        Be sure to add a protein source if there are signs of protein deficiency (poor top line, poor hair coat, poor hooves, hay belly, connective tissue strains). I have several blogs on chronic protein deficiency. This will help to eliminate food aggression which is not hunger but the more looking for a missing need in their food. Adding the missing amino acids will satiate the horse as well as minimizing the excess glucose in the diet. The goal is to attain slow weight loss over the summer and through the winter. The test is for a normal blood insulin value next April. Please come back and let us know how you did.

  15. A friend mentioned that her gelding who is on The Diet is urinating a lot and seems to need additional calories. Would urinating a lot be any indication of excess UA stressing the kidneys?

    1. I do not know but humans excrete about 70% of their UA via their urine. This is due to a genetic mutation in humans where UA cannot be further oxidized by the enzyme uricase. Therefore there is more to excrete. This lack of uricase has not been demonstrated in other animals but the assumption is that it is still active. Therefore there should be less UA to excrete. But on the flip side the research also shows that there is an increased production of UA due to the things I discussed in this blog. Again I do not know if there is any evidence that there is an increased osmotic draw of UA into the urine. You will need to ask someone in this field.

      In the meantime your friend should have a urinalysis performed and discus the results with her vet.

      “Additional calories” is a common thought as a horse that is using body fat for energy will lose the fat and reveal the lost muscle. However these horses are usually lively and willing to perform their tasks. After the excess fat is removed and the amino acids / top line restored the diet can be adjusted using the eye as well as knowing the season (middle of winter or middle of summer).

      1. Great information Doc T ,once Java was off the grain there was a difference .No stocking up in hind legs,better top line.thanks to you and Kathy,more people should be educated on this and to stop giving sugar to their horses ,Thanks again for the wonderful information you share😀

        1. You’re welcome Rochelle. More and more people are listening and for those trying to understand why it works, this blog attempts to fill in the gaps. Hopefully a researcher will take the information we have today and discover all of this to be true in horses with hard data. But that will never happen because there is no money in it.

          Until then all we have are the hundreds of comments on these blogs and in the FB group “The Horse’s Advocate” where there are so many positive testimonials. I am grateful to all who have listened and tried removing the starch in their horse’s diet and have realized with their own eyes the improvement in their horses. Thank you ALL, Doc T

  16. Thank you for this blog….i will need to reread it tho….and thanks for answering my questions….

    1. We don’t have good data about horses other than measuring UA in exercising horses. However the process seems to be the same in all mammals according to the research being done in humans and lab animals.

      AMP normally is recycled into ATP to “recharge the battery” so to speak. But when fructose is used for energy production enzyme AMP deaminase converts AMP into uric acid.

      In humans, uric acid is associated with gout. This is when UA forms crystals which settle into joints. Foods high in purines also cause high UA. Purines are foods high in DNA and RNA such as meat, shellfish and yeast (think beer). However AMP is actually the best representation of a purine. And many horse feeds have yeasts added as a “probiotic.”

      So the high UA in tested mammals come from 1) the food we eat and 2) fructose. In humans table sugar is half glucose and half fructose. High fructose corn syrup is 60% fructose and when in liquid form, the fructose swiftly moves to the colon where it appears responsible for the formation of colon cancer.

      Finally, the most revealing evidence that fructose is causing problems is that in humans AND ALL ANIMALS TESTED, the removal of fructose from the diet eliminates metabolic syndrome, obesity, IR, diabetes and hypertension. So why not in horses?

        1. I do not know of horses eating fish though I did see the YouTube of the Icelandic horse eating fish whole as fast as they could put it in the horse’s mouth. Horses are hind gut fermenting animals specifically designed to eat cellulose.

          As far as humans go, I am not an expert. However shrimp and beer should be eliminated if you have gout. Eating raw or grilled fish have more advantages than disadvantages but all meat are high in nuclear material which are the definition of purines (UA being a purine). This new information presented here would also have us all eliminate all fructose as well as diminish or eliminate starch to improve our blood UA levels.

          And there is also evidence that if you are dehydration to any degree and you eat salt before rehydrating will trigger Aldos reductase and convert glucose into fructose. In other words, if you eat the salty fast food burger AND the salty French fries (high glucose) and THEN drink the soda with sugar or high fructose corn syrup it is too late. If you are thirsty you are already converting that meal into fructose with metabolic syndrome and hypertension following.