The Equine Practice Inc, Travels With Doc T

Supplements – Decomplexicating Equine Nutrition Part 10 of 12

The nitty-gritty of nutrition seems to lie in supplements which include 1) the elements we call minerals, 2) the electrolytes we call salts, 3) the molecules we call vitamins and 4) the herbs. I hear a lot of people proclaim that paying attention to and supplementing for the lack of these things will enhance the health of the horse measurably. One example of this is the addition of magnesium to help calm the horse.

I have said this several times in these blogs on nutrition and it’s worth repeating here. It is NOT the addition of things that makes the horse healthier. It is the removal of things harming the gut microbes that will turn the health your horse around. Before we go further, let me introduce you to what these things are.


Vitamins are organic (containing carbon) compounds occurring naturally in the foods eaten and several are required to prevent disease in humans. However in the horse, very few vitamins are required due to their very different diet and digestive system. Deficiencies have occurred in some vitamins but only in horses that are starved or have been fed poor quality pasture and hay. This include hay that is over a year old. In other words, if a horse is outside eating good pasture during the growing season and is fed hay during the dormant winter season then there are no known vitamin deficiencies in horses according to extensive research done in the field of equine nutrition.

Yup! All those vitamins you are feeding are not necessary as long as your horse is not experiencing starvation.

The elements that make up all vitamins are the same as proteins: Carbon, Hydrogen, Oxygen and Nitrogen. A few have Phosphorus or Sulfur and one has Cobalt. All of these elements can be found in the foods the horse eats and thanks to the bacteria in the gut and the functioning liver, it is unlikely that horses suffer from vitamin deficiencies unless they are starved.

Vitamin A – Deficiencies have been reported during severe droughts over a long period of time. It is derived from carotene found in plants. Carotene in stored hay will diminish over time. Deficiencies include loss of appetite, night blindness, excessive tearing, thickened corneas and skin, reproductive problems, respiratory problems, seizures, blindness, bone disease and decreased disease resistance. Chronic (3 to 4 months) over-supplementation can cause depression, unthriftiness and death. Prevention is good pasture and hay.

Vitamin D – deficiency is unlikely when fed sun cured hay or they have adequate exposure to sunlight. Deficiency causes loss of appetite and weight loss when deprived for about half a year. Over-supplementation with Vitamin D in horses has been shown to cause several system dysfunctions (bones, kidneys) that can lead to death in 3 to 4 months.

Vitamin E – There are no known deficiencies however in young horses a lack of Vitamin E helps with red blood cell stability. There is some evidence that Vitamin E combined with Selenium may prevent white muscle disease.

Vitamin K – This is not necessary in horses as it is produced by the gut microbes. Vitamin K given at the manufacturer’s recommended dose caused kidney damage in one study with bloody urine formation.

Vitamin B – Additional B vitamins are not needed in the horse due to sufficient amounts in good quality hay and the production of B vitamins by the gut microbes in the hind gut. However, in horses with colon damage (ulcers) or that are stressed, these microbes may not produce enough B vitamins.

B-1 (thiamine) deficiency may occur in horses fed poor quality forage, bracken fern or mare’s tail.
B-2 (riboflavin) deficiencies have not been reported in horses. The one disease associated with a deficiency in the past has now been attributed to another reason.
B-3 (niacin) deficiencies have not been reported in horses.
B-5 (pantothenic acid) deficiencies have not been reported in horses
B-7 (biotin) deficiencies have been shown to cause defects in the surface of hooves in pigs but no requirement has been made for horses.
B-9 (folic acid) low blood levels can occur in horses without pasture but no known diseases.
B-12 (cyanocobalamin) deficiencies have not been produced experimentally in horses

Vitamin C – not a requirement in horses as they produce enough vitamin C in the liver.


Minerals are elements (see the periodic table of elements, also known as atoms) required by horses to perform necessary functions in the body. For example, iron is needed to attach oxygen to the hemoglobin protein within the red blood cell. Minerals cannot be made by the horse and therefore they are considered essential for life and are consumed in the food they eat. The 5 major minerals in humans are calcium, phosphorus, potassium, sodium and magnesium. The remaining minerals are called trace elements and include sulfur, iron, chlorine, cobalt, copper, zinc, manganese, molybdenum, iodine and selenium.

Calcium (Ca) and phosphorus (P) are essential in bone formation especially in young growing horses. While a deficiency in calcium is almost impossible except in extreme cases, phosphorus deficiency can cause a series of problems. Remember ATP in the mitochondria? The “P” in ATP is phosphorus. On the flip side, too much phosphorus actually prevents the absorption of calcium and will cause soft bones (rickets). This is why dicalcium phosphate is added to all grain mixes because all grains, especially wheat bran, are high in phosphorus. This was called “Miller’s Disease” a long time ago when horses were fed the byproducts of the milling industry. Today, wheat byproducts are still fed to horses but because dicalcium phosphate is also added, the disease called Nutritional Secondary Hyperparathyroidism (big head disease, brain disease, miller’s disease), a nutritionally caused calcium deficiency, is avoided.

Magnesium (Mg) is often added by horse owners to calm their horses. A deficiency will cause hyper-irritability, tetany, glazed eyes and collapse so it makes sense to add magnesium to calm the excitable horse. However, the primary cause of magnesium deficiency is the blocked absorption of it caused by excessive feeding of calcium or phosphorus. So if horses are being fed excessive phosphorus from wheat bran and wheat middlings and then more calcium and phosphorus is being added in dicalcium phosphate to counter the high phosphorus, then it would be logical that the horse will become deficient in magnesium. Interesting… This would be an argument to avoid feeding grains with their high phosphorus content plus the added dicalcium phosphate rather than adding magnesium. Maybe this is the primary reason why removing grain from the diet causes horses to settle down quickly.

Potassium (K) – A deficiency in this element is not common in horses but an excess caused by a genetic mutation in Quarter Horses will produce muscle weakness called hyperkalemic periodic paralysis (HYPP).

Sodium (Na) and chloride (Cl) (salt – NaCl) – These elements are everywhere and are necessary for life in all systems within the horse’s body. This is why it is offered free choice to horses. I have rarely seen deficiencies but on occasion I have seen a horse over eat salt devouring a salt block in little time. This causes the horse to drink large amounts of water and urinate a flood of water. I call this kidney medullary washout requiring the normal kidney gradient to be reestablished.

Iodine (I) – Too much or too little iodine in the diet will cause goiter, a term used to describe an enlarged thyroid gland. A third cause of goiter has an unknown cause (idiopathic). In all cases I have seen there is usually being fed a supplement with seaweed, specifically kelp which is high in iodine. Removing this supplement reduces the goiter to a normal size. The horse shows no ill effects from a deficiency or an excess of iodine.

Iron (Fe) – The information about iron is extrapolated from humans and other animals and is presumed to be the same. Iron is conserved by the horse with very little loss with the exception of severe bleeding. This is called efficient conservation and because of this, iron is only absorbed when needed. A deficiency in iron is call anemia which leads to exercise intolerance. Excess iron supplementation (injected, fed or in the environment) can become lethal by replacing other minerals and causing tissue weakness (hemochromatosis, liver disease, diabetes). Older horses may have higher levels of iron due to chronic storing of excess iron. There is a blood test to determine iron levels in the horse.

Copper (Cu) – Deficiencies are not common in horses. It may be part of the development of osteochondrosis in growing foals. Toxicity has not been established in horses.

Zinc (Zn) – Deficiencies are not common but toxicity has been reported in fields located near smelters of metals.

Manganese (Mn) – This is not an essential element but in one case where excessive limestone was added to a hay field, the hay then became low in manganese and the subsequent foals born from mothers eating this hay had severely deformed limbs. However deficiency and toxicity are rarely found in horses fed good quality pasture and hay.

Selenium (Se) – This mineral is low in some soils and a deficiency can be seen in newborn foals as a muscular dystrophy called “White Muscle Disease.” They are often too weak to stand or swallow and die of starvation. Testing and then supplementing the mare before birth will avoid this disease. Deficiencies in horses older than newborns horses have not been shown to cause problems though most commercial feeds add selenium routinely. Toxicity with selenium is more of a concern in the western states in America (Wyoming, Colorado, South and North Dakota, Montana, Utah and Nebraska) because some plants store selenium which are then eaten by the horse. Horse owners living in these areas are aware of this and avoid these plants. Toxicity causes “Blind Staggers” which may include lethargy, unsteady gait, difficulty breathing, diarrhea, increased pulse, respirations and temperature and death. While toxicity is not common in commercial feeds, it is a potential threat to all horses eating commercial mixes. With great sadness, my friend watched 12 polo ponies die a terrible death in front of him after all the horses had been given an IV medicine made with an accidental 10 fold amount of selenium. Care should be taken when feeding anything with selenium supplementation.


Electrolytes are elements that when added to a solvent like water, either lose or gain an electron becoming a charged ion. If a positively charged electrode is placed in one end of the water and a negatively charged electrode is placed in the other, an electric current is created by the charged ions moving through the water to either gain or lose an electron and become balanced (no charge). This is how the nerves, muscles and everything else work in all animals including your horse.

The common elements in horses that can become “charged” include sodium (Na+), chloride (Cl-), potassium (K+), calcium (Ca++), magnesium (Mg++), carbonate (HCO – – –) and phosphate (PO4 – –). The + and – signs after the elemental abbreviation means that the element is in the charged or ionic state. Why is this important in horses? Because the only way to get these elements into a charged state is to keep them apart and separated. This is an activity every cell in the body expends energy on every moment of the life of the horse. It is just like two lovers each in separate rooms; there is great potential but a wall between them. When the potential between charged ions is signaled for and the charged ions come together, an action occurs through this created current by the movement of ions across the wall. Every action made in the body is because a potential between 2 charged ions created an electric current through an opening in the wall between them. Such actions include contracting a muscle, sending a nerve transmission, a heart beat, a thought, the scratching of an itch – everything. These currents are what is measured in the EKG of your heart.

The charged elements are physically forced into the spaces outside the cell (extracellular space) or inside the cell (intracellular space). Na+ is primarily outside the cell and K+ is primarily inside the cell. Their concentrations are precisely controlled in the horse with the gradient between the two constant. The same is true with all ions creating potentials across solid membranes. Whenever ions are allowed to come together, the potential is experienced, the current made and the action occurs.

The main causes of electrolyte loss in horses are extreme sweating and diarrhea. If your horse isn’t sweating (too cold, not exercising) or doesn’t have severe diarrhea, then there is no need to supplement with these elements because there are plenty of these elements in the food they eat. In addition, almost every electrolyte supplement for horses contains sugar in some form which is unnecessary to add to the diet.

Some signs of electrolyte deficiency in horses include muscle cramping (not exertion myopathy which is a genetic disorder), muscle exhaustion (calcium reserves are depleted) and synchronous diaphragmatic flutter (“Thumps” “Hiccups”).

HYPP is an electrolyte imbalance from a genetic mutation occurring in heavily muscled Quarter Horses within a family line. The potassium on the inside of the cell and the sodium on the outside of the cell are allowed to freely cross the muscle cell wall eliminating the potential to make a current and muscle contraction in a thoughtful manner.

Thumps occurs in dehydrated horses when the potential between ions accidentally is triggered by the electric current of the heart beat across the gap between the heart and the phrenic nerve lying across the heart on its way to the diaphragm. As the heart beats, the diaphragm contracts synchronously with the heart beat creating a jerk of the diaphragm (a hiccup) ranging from mild to severe thumping. It is cured with rehydration using electrolyte solution IV.

Herbs and Spices

It has become popular to add herbs (plant leaves or flowering parts) and spices (plant seeds, berries, bark, roots, and fruits) to the diets of some horses usually for a specific benefit. In humans they have shown a beneficial effect on the mitochondria of the cell. The part of these plants being attributed to these benefits are the polyphenols which are a group of plant chemicals that benefit cellular health and in particular, mitochondrial health. Coffee beans have the most polyphenols in human food but many other herbs and spices have them too including oregano, thyme, black pepper, turmeric and others.

There are no bad side effects of adding herbs or spices in moderation and in eastern (Chinese) medicine they are relied upon. Western medicine has not embraced these plant medicines as a form of therapy and I don’t think there are many good and reliable studies done on their use here. But lets look at it another way. Would there be any need for herbal therapy if the horse has a healthy and non-inflamed gut? Ginger helps an upset stomach in humans but why is the stomach upset? Herb and spice plants are found growing in the wild, but not everywhere and not year round. Could there be a lectin or carbohydrate conflict if used indiscriminately?

All herbs and spices are plants and therefore available to the horse if growing in their area. There are no known toxicities when eaten in the wild but some are toxic when given continuously and in excessive amounts for supplementation. The principles of feeding them are similar to all other plants – feed only when in season. Again, in a healthy horse with a normal gut microbiome, there is probably no need to supplement with herbs or spices unless guided by an experienced practitioner for medicinal purposes.


1) Adding vitamins to the horse’s diet is unnecessary unless they are starving or on severely poor pasture and hay.

2) Adding minerals beyond the requirements of the horse may cause health issues. Adding them to pregnant mares and new born foals may be indicated depending on the environment where they live and the quality of forage available.

3) Adding grain, especially wheat, with the addition of extra calcium and phosphorus may cause a magnesium deficiency with irritability as a result.

4) Adding electrolytes is only necessary when the horse is or will become mildly to severely dehydrated through excessive sweating or diarrhea.

5) Herbs and spices have a place when prescribed by a medical practitioner. However in a horse with a normal gut microbiome and not starved, adding these may be unnecessary.

6) Save money by not feeding extra vitamins, minerals, electrolytes or grain. Invest in feeding the best quality pasture and hay you can purchase.

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Comments 20

  1. This article about vitamins, minerals, etc was very interesting and helpful…investing in good pasture and hay makes good sense!!!

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  2. Informative article! I basically came to the same conclusion after years of dumping tons of money into mineral/vitamin supplements, testing hays to see what was missing, etc., etc. I quit supplementing and went back to the basics. I was never a supporter of feeding grain to my horses so don’t think I ever really did or if I did it was minimal, which may explain why they don’t look or act their age. My horses (ages 28 & 30) seem to be doing better now that I cut everything out. I do have a Redmond’s salt rock and some loose mineralized salt that they can eat or not. Someone recommended a product called Thrive Feed to me ( – are you familiar with it? If so, your thoughts? Based on your article, I think I know what your response might be. Thanks!

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      Thanks Lorraine – Remember, It’s what you take away, not add. Though I am an advocate of adding protein to most horses due to the chronic protein deficiency.

      Thrive seems to have its heart in the right place. But there are some things I would not feed based on their ingredients which are “Dehydrated alfalfa meal. Timothy grass meal. Grain sorghum. Whole soybean meal. Rice bran. Dried kelp meal. Calcium carbonate. Salt. Schidigera extract. (Yucca) L-Lysine monohydrochloride. DL-methionine. Potassium sulphate. Magnesium sulphate. Monodicalcium phosphate. Diatomaceous earth. Zinc sulfate. Ferrous sulfate. Copper sulfate. Calcium iodate. Cobalt carbonate. Vitamin E supplement. Niacin. D-Calcium pantothenate. vitamin A supplement. Thiamine mononitrate. (source of Vitamin B2) vitamin B-12 supplement. D-Activated animal sterol. (source of vitamin D-3) Pyridoxine hydrochloride. (source of vitamin B-6) Folic acid. Menadionine sodium bisulfite complex. Manganese methionine complex. Cobalt glucoheptonate.”

      What I like is alfalfa, timothy and soybeans (and salt). Keep it simple. What I possibly don’t like is the sorghum as many think this is a resistant starch in humans. The rest are supplemental and as you read, I think most of these in a healthy horse are unproven in their beneficial effects. Thanks again for posting and telling everyone about your vibrant elders.

      1. Thank you for your reply, much appreciated! Yes, there are a lot of ingredients I don’t like either. The recommendation was made because my horses’ molars are almost completely gone so they can’t eat enough hay to maintain their weight. They have access to Bermuda (only hay both can eat without a problem) 24/7 to keep them ulcer free and busy; plus they are supplemented with Timothy/alfalfa soaked pellets.

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          All they will need is pasture, hay (cubes or chopped so they don’t need perfectly functioning cheek teeth) and protein. It is the protein that seems to be forgotten (see the previous pillar 8 blog). Also, to maintain some fat on these elders, you can add coconut meal (Coolstance – or, if you can’t get that, Renew Gold (which has Coolstance in it). This will add the extra calories for winter in older horses without adding inflammation.

          1. Thanks again. They wad all pasture type hay (and any long-stem hay) and would not eat the CoolStance I bought for them a couple of years ago. I also tried chopped hay and they wouldn’t eat that either (tried 4 different brands). I’ve not tried cubed hay because it would have to be soaked and based on the chopped hay experience I doubt they’d eat it (I tried soaking regular hay and they wouldn’t eat it). They are definitely challenges to feed!! Feeding soaked pellets (Timothy/alfalfa mix) – they’ll eat them and it keeps their weight up – and 24/7 Bermuda hay seems to be the best combo I’ve found. So, looks like protein and fat are what they’re missing. I’m afraid they won’t eat the Renew Gold because of the CoolStance in it. I just hate buying things and having to throw them out because the guys won’t touch it. Will go back to your articles on protein and fat and see what I can add. These horses are really lucky (people tell me this all the time) that I spend so much time figuring out how to keep them healthy and happy!! That’s why, other than all the white hairs, they look and act 5-10 years younger than they really are. 😀

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            Adding fat is usually inflammatory. Coconut meal and their fat are NOT inflammatory.

            Horses get their fat from cellulose. Please read The High Fat Diet to learn about this. Adding oils is NOT helpful.

            As far as them “not liking” the hay types you bought them, if it gets cold enough and they get hungry enough, horses will eat down the wood of the barn. Believe it or not, once they start to eat what is good for them (grass / hay (any form)) they will actually keep their weight on. Remember that the definition of “weight” is mass times acceleration. What makes that mass is protein, fat, muscle, minerals, water and gas. Horse owners often confuse “weight” with just fat but in reality, as the horse loses fat the true loss of muscle is seen.

            You are in the best time of year to do these additions for your horses. No added fat necessary because they will get that from the grass and fresh hay. Add 1 gram of effective protein (NOT crude protein) per pound on body weight (about 1 pound of a good soy bean, whey protein and alfalfa mix) per day. Do this for all summer and then evaluate these horses before winter sets in. I’ll bet they will look even better than they do now – and do well over the winter.

  3. Hope you had a great Easter and didn’t eat to much. Thanks for the help and info on careing for my horse.

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      Pasture, hay, water, Himalayan salt, ProAdd (Nutrena). I could easily replace ProAdd with soybean meal without vitamins and minerals, but for our area this is just easier.

  4. Thank you, thank you, thank you! I just stumbled upon your website today and have literally been reading the hours away! I have been struggling with a direction for my small breeding operation… long story short, and many attempted avenues, I actually began my grain-free quest back in October. I put everyone, weanlings/yearlings/broodmares/performance horses/pasture puffs on alfalfa pellets and a mineral. I have already seen my “higher than a kite yearling” turn into a calm, cool, collected citizen, so that alone makes me a believer! I’m so thankful I read everything when I did, as my 16 year old performance horse is starting to look a little “light through the top” as we get into the worst of our winter… I literally have a bag of oats in my truck that I was to start supplementing her with, but after reading what I have, I’ll be returning them! I was recently concerning myself with not providing enough amino acids to my growing horses, but I think what I read today brought me a little reassurance that I didn’t totally ruin my babies yet… however –

    I plan to do the official switch/addition to soybean meal after the winter passes, so I can actually see the results rather than 4″ of hair (yes, it actually was -55 with the wind here in WI today) and at that point I’ll be out of my current vit/mineral supply and not going back… that being said, with many-year-old hay (I do have a recent test, it’s still very respectable – however VERY high in calcium vs phosphorus…), coupled with the mares/babies, what mineral supplement would you add? I’m slightly obsessed with the “calculations”, however after reading what I have today, I’m attempting to tell myself to relax… maybe those numbers don’t HAVE to read 100%?

    I checked into Barn Bag and Farriers Formula, but due to the “numbers” still being low in phosphorus, copper, and zinc, I found I’m getting a better balance with MVP Mare Foal II – first number of ingredients: Soybean meal, alfalfa meal, corn distillers dried grains with solubles, L-lysine monohydrochloride, DL-methionine, calcium carbonate, monocalcium phosphate – do you think that level of corn distillers will be a problem? I would be feeding a 1400# mare 2oz/day. Also, at what age would you stop supplementing “weanlings”? 9mo? 12? With an older hay supply, would you suggest supplementing all? Also, when the young ones hit training/competing (barrel horses), would you just add additional alfalfa pellets for calories, or at any time would you look to oats again? Mineral at that point?

    Gosh, I could go on forever, so sorry about the novel and so many questions! If I may suggest, it would be fantastic if your site had a “FAQ” section.. I’m loving your answers throughout these comments!

    Thank you!!

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      Why wait until spring to add soy bean meal? If your horse’s top lines are already affected then they are converting their own protein into fuel (glucose). They will need the amino acids provided by the SBM now. You don’t need to “see the results” because adding top line will take from 6 to 12 months to do. If the hoofs look bad then the results will be seen there in 2 to 4 months. And the hair coat should shed beautifully as the days get longer – with March 21st a target date for shedding (6 weeks away).

      I don’t add a mineral supplement for 3 main reasons. The first is that the best mineral supplement is the ground water they drink followed by salt with minerals. Second is the absorption of minerals is affected by gut inflammation and protein deficiency as well as the pH of the water. Without measuring the exact mineral content you really do not know the effectiveness of supplementing. Third, with the exception of starvation cases, I do not see mineral deficiencies in healthy horses. To my eye, the signs of protein deficiency is obvious but I do not see any mineral deficiencies. Adding SBM as a protein source provides a broad spectrum of absorbable amino acids which helps in the absorption and utilization of minerals.

      As a rule, if your horse is not sweating then they are not losing minerals as electrolytes. Iron in humans is highly regulated. The addition of dicalcium phosphate as a prevention of rickets in grain fed horses prevented the absorption of magnesium leading to hyper-excitability in most horses. Can the over supplementation of other minerals also have an adverse effect on the horse? I would rather let the horse find the minerals he needs in the water and food he consumes. The mantra here is to remove things from their diet, not add them except to help them survive in -55 degree weather. Hay is a supplement and so are blankets. Even a scoop of de-hulled (cleaned) oats won’t hurt for a bit until the temperatures get higher. But avoid “corn distillers dried grains and solubles.” This is inflammatory and is a by-product. Lysine and methionine are 2 of the 3 limiting amino acids and isn’t bad but is unnecessary when feeding SBM. Calcium carbonate is “Tums” and as an antacid is changing the pH of the stomach which may decrease the ability to break down proteins for absorption. It does help grain fed horses to feel better. The mono calcium phosphate usually is followed on the ingredient list with dicalcium phosphate. These ingredients prevent Ricketts caused by the high phosphorus of grains but also prevents the absorption of magnesium.

      Adding “calories” is a misconception. The energy produced from ketones derived from cellulose is more efficient at producing energy than energy derived from glucose in a starch meal (grain). In an ideal world, horses would only eat what they found in their travels. As grazers (technically speaking as opposed to browsers), the horse will get all the energy they need to perform with pasture, grass hay, a flake of alfalfa, 1 pound of SBM per day, salt and water. Supplementing is something horse owners do to avoid missing something and in doing this they really complicate things by dividing horses into age groups. Until I start seeing squirrels and other animals of the world eating different diets because of their age (for example senior squirrel feed or ration balancers), I would not recommend horses be fed anything but what they were designed to eat – ground plants. This is just marketing at its best which is geared towards people trying to do their best for their horses. Unfortunately there are too few horsemen old enough to remember what horses were like 50 or more years ago. They look great, had fewer illnesses and were fed less.

      To summarize – if it is extremely cold you must do what is necessary to help your horses survive. This includes extra hay and alfalfa (both equal in calorie production) and some cleaned oats (a source of sugar calories used to restore glycogen stores in the liver and muscles). Add SBM as soon as you can to restore any amino acid deficit. Have plenty of water available. Spring is coming and so is the pasture. Your goal right now is to eliminate gut inflammation and restore the amino acid reservoirs. The minerals will take care of themselves and if they don’t you can always add them once a deficit is discovered (but it won’t appear based on not seeing deficiencies reported in non-starved horses). See – I can write novels too. Doc T

      1. Hi Doc T, I have a question regarding your comments about why you don’t add minerals. I agree and 20 years ago my horses only got grass hay and think I had a salt block out for them. Very simple and they were healthy. But, they got older and so I started adding a whole bunch of expensive stuff to compensate for their age-related “deficiencies” and lack of quality forage. My horses are in the city, in the desert (Phoenix), on a dirt lot, no pasture, don’t have ground water to drink except when it rains hard and we have a small lake. I free-feed various hays (Bermuda, Timothy, Orchard, once in awhile a little Alfalfa) and am still trying to figure out how best to give them salt (loose plain OR loose mineralized OR plan/mineralized salt blocks – have tried all three ways over the years). Given that the nutritional content of cut & dried hay is not very high and they drink city water (we have a whole house water system so chlorine and other harmful chemicals are filtered out), are healthy horses still able to get/make all of the minerals they need? I think you are saying yes. The one thing I’ve not done is the SBM – I still haven’t gotten myself over my bias against soy, but may try it. If yes, my husband and our pocketbook will be ecstatic! Having gone through less is more to more is better and now back to less is more is liberating! Thanks!

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          Thanks Lorraine. You have a special case in that you have limited pasture and “clean” water. Are there any horses in your area suffering from a mineral deficiency? Maybe ask your vet. I’m not interested in the standard answer I hear everywhere, “This area is low in selenium.” What I want to know (and would love to hear your findings here), are there any cases of mineral deficiencies in horses fed the same way you are feeding your horses in your area. Starvation cases should not be included.

          If you decide to add minerals please remember that many mineralized salt licks have corn syrup and molasses added. A pure salt such as Himalayan or sea salt may be good enough. Also remember that electrolytes are minerals with added or lost electrons and most electrolyte powders have sugar added for absorption (think Gatorade).

          While so many horse owners focus on minerals, few seem to understand the importance of adding back the lost protein in horses either chronically deprived of broad spectrum amino acids in the diet or the chronic loss of amino acids from self absorption (gluconeogenesis). Minerals are transported across the gut wall and distributed within the body by proteins. For example, hemoglobin is a protein with iron incorporated into it for transport of oxygen to cells via red blood cells. Deficiency in just one amino acid causes a depletion of so many proteins just like a dictionary missing one letter prevents the use of a bunch of words (no “W” and you can’t write the sentence “Where will we be tomorrow?”).

          Soy bean meal is safe in horses with no reported evidence of illnesses from genetic modification nor feminization from estrogens. It is a legume which are accepted by horses as are all other legumes such as alfalfa and peanuts. As a meal, the lectin containing hulls have been removed and the inflammatory oil has been removed. I would dare say that the feminization of stallions by castration is more extreme than any SBM diet could dream of. But more importantly than knowing that genetic modification has occurred in 94% of all foods consumed is the observation that most of the horses I see across this country show chronic protein deficiency. If you want to add non-GMO SBM that’s fine and it does exist. There are also other sources of amino acids.

      2. When you say ground water, do you mean “Well” water? My water is not from a well, it is from a public source. (started the “no grain” Feb 11, 2019) ALSO, Wondering do horses become depleted of vit-min from hard work? I do 3 Day Eventing. Thank you.

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          Yes, ground water is well water. Treated water may have some of the minerals removed and others added such as chlorine and fluoride.

          Hard work in warm weather may cause a depletion in electrolytes. If it is severe then “thumps” may occur. However if you horse has access to minerals, the electrolytes lost will be restored.

          Vitamins are proteins and like all proteins, they have a half-life of 2 to 4 days. Exercise may shorten the life span of some connective tissue protein as well as vitamins and other proteins due to stress and cortisol. But actually exercise will demand more amino acids due to the horse building more connective tissue to support the forces applied to it. Most human exercise gurus suggest ingesting the protein supplementation within 1 hour post exercise. I would assume this to be true for horses though I have not read this. However the routine ingestion of maintenance protein should be adequate for vitamin production. Remember a healthy gut microbiome is important for many vitamins to be made.

  5. Thank you for your response – I always learn a lot from you. I am actually in between horse herds right now (my senior geldings passed on a couple of months ago and I’m almost ready to start my new herd) – I’m in the planning stages for feeding the new herd.

    Actually, most of the horse people I know around me have the same no pasture, no clean water, small space issues that I have. Horse property in the metro Phoenix area is very expensive and most people, including me, cannot afford 10 acres, nor 5 acres, not even 2.5 acres. Many horse people I know have less than an acre or board their horse who lives in a stall, isolated, fed twice a day and may be turned out for a couple of hours three times a week – thankfully, my horses have a lot better situation than they do. From time to time I toy with planting organic Bermuda grass in part of the horses’ habitat; may actually do that one day.

    I’m not keen on standard answers either and usually question them.

    My feeding regimen is always a work in process so it’s hard for me to compare to others. I’m not aware of mineral issues of anyone who feeds primarily grass hay, or for those who feed Purina Senior Feed and whatever joint supplement, colic prevention, vitamins, minerals, etc. their vet or Dynamite Specialty Company recommends. Most of us lay people wouldn’t recognize a mineral deficiency without a vet experienced in ways the deficiency(ies) would present itself. I so need to get back to your Horse Advocate nutrition program!

    When I was feeding minerals, it was Horse Tech’s Arizona Copper Complete ( – supposed to balance out the high iron and low copper issues here in the Southwest). The mineral block I last used was a Redmond Salt Block (no additives that I know of); the last loose salt I fed was Dynamite Natural Trace Mineral salt (no additives). I never fed electrolytes as I wouldn’t drink Gatorade myself. I learned the importance of protein when my seniors lost their topline (I looked but never found an amino acid supplement that was complete, so saved money there – I thought about adding SBM but my bias got in the way. I’ve now, based on your input, gotten over the bias). They had lost their molars a few years ago (years of vets power tooling them away before I learned the importance of a competent equine dentist) so feeding them enough to sustain them was a huge challenge. Had to resort to Nutrena Safe Choice Dry (minimal molasses) to keep them from looking like starved horses in addition to their many pounds of Standlee pellets three times a day.

    My new plan, based on my experience and your input: the new herd (younger horses) will get a variety of grass hays, some Alfalfa from time to time, non-GMO SBM (will add it to Standlee pellets so the horses will eat it), Redmond Salt Block (because I still have one — unless you think the Himalayan or sea salt is better). Will see how that goes. If I add anything it may be the Arizona Copper Complete (flax meal based – not sure if that will interfere with the SBM). I will definitely report back on how the new simplified (back to the original basics!) works out.

    P.S. If you know of any horses that need a great home (and within a day’s drive of Scottsdale, AZ), let me know! I’m partial to BLM mustangs, grade horses and minis. Pedigrees mean nothing to me, only the heart (good or hurt) of the horse is important. All my animals are/have been mutts. 🙂

Your thoughts are important for all to hear and may help others to learn from your experiences. Take the time to add to the discussion. However due to time limitations I will probably not answer direct questions to me. Thanks, Doc T

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