Topping Off Hay Diets

Hay is just dried grass and grass is the horse’s natural food so it shouldn’t need any supplementation – right? Wrong.

Hay is a natural feed for horses but it lacks key nutrients.

Variety is a major difference between the diet of feral horses and that of  domesticated horses fed hay.  The feral horse consumes many different plants grown on a variety of soils while the domesticated horse eats the same thing 24/7 for prolonged periods. The variety gives the feral horse a wide range of mineral intakes which tend to balance themselves out. No single hay is ever nutritionally complete and balanced.

Hay is also deficient in the most important nutrient – water.  Hay is like grass jerky. A constant supply of fresh, clean, palatable water is essential for digestion, normal gut motility and hydration. Snow is not good enough!   Very cold water may also not be consumed in sufficient amounts. Horses prefer water at body temperature.

Compared to fresh grass, hay is lacking in omega-3 fatty acids, vitamin E and vitamin C. These nutrients are rapidly destroyed in the drying process and are key to balanced immune function.  The horse can manufacture vitamin C in sufficient amounts to prevent full blown scurvy but studies have shown that levels drop precipitously in horses not on pasture.

As hay ages, levels of the vitamin A precursor carotene drop off to the point most hays fail to meet requirements by the time they are 12 months old.  Hays that are yellowed rather than green also have low levels.

Finally, both hays and fresh grasses of all types are deficient in sodium/salt. Feral horses make periodic pilgrimages to areas of salt deposits in their range. The domestic horse should have constant access to free choice salt and if they don’t consume enough either add it to bucket feeds or dissolve and spray on hay. “Enough” is 1 oz/day for the average full size horse in winter and 2 to 4 oz in hot weather.

Supplements based on flaxseed are ideal for omega-3 fatty acid supplementation.  Feed 4 to 6 oz/day. Vitamin E requirement is 1000 to 2000 IU/day.  Start vitamin A supplementation at 20,000 IU/day when hay is 6 months old; increasing to 40,000 to 60,000 IU after it reaches 12 months old.  Vitamin C should be used judiciously since large doses will increase iron absorption which most horses don’t need. If supplementation is thought to be desirable for tendon, ligament, joint or lung support keep it at 5000 mg per dose or less.

Mineral requirements for your hay will vary depending on the type, where it was grown, age at cutting, soil treatments used and even the weather.  The most accurate way to balance hay is based on a hay analysis. Your local agricultural extension agent can direct you to a laboratory.

If analysis isn’t possible because the supply changes too frequently, the Ag agent can help get you information on typical profiles for the area where the hay was grown. It’s not ideal, but better than blindly buying a supplement without considering the levels of minerals in it. If you own a metabolically challenged horse the analysis is critical to safety. Include tests for starch and ESC (ethanol soluble carbohydrates = simple sugars).

Like anything else new, correctly supplementing hay will seem like a lot of work when you first do it but the obvious benefits to the horse in terms of coat, skin, hoof, energy and immune system health are usually so obvious you will never go back.

Eleanor Kellon, VMD



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Feeding Wheat Midds

If you are a label conscious owner you have undoubtedly seen the ingredient “wheat midds” listed on many products. You may also have had an immediate negative reaction, writing them off as nutritionally inferior by-products. That would be a mistake.

The most nutritious portions of milled wheat end up in the midds.

Byproducts is not a synonym for waste material.  It also doesn’t mean that the product is “highly processed”, which is a very common claim by detractors.

The major end product of wheat is flour, especially white flour. Most people recognize that white flour is greatly deficient nutritionally compared to whole wheat flour. What you might not realize is that all the nutritionally dense components of whole wheat compared to white flour are what ends up in wheat midds.

The term “midds”, short for middlings, refers to parts of the whole wheat grain between the raw parent grain as harvested and the end product of wheat flour.  It’s removed in the middle of the process of flour production.

When wheat comes into the mill, the first few steps involve cleaning. The grain shipment is sent through a series of sieves/screens, blowers and even magnets to remove most of the contaminating material from harvesting.

The wheat then goes through grinding, screening and blowing which separates the starch/flour rich segment of the grain from the outer and inner layers. The midds include the bran and wheat germ, fractions all can agree are the most nutritious. In fact, if the wheat was being processed by a plant focusing on production of wheat bran or wheat germ, the high starch flour portion would then be considered the “byproduct”.

Wheat midds are high protein (18+%), moderate starch (average 25%) and moderate fat (average 5.5%) that comes from the wheat germ.  The only processing involved is physical means of sifting, grinding, etc. that separates these fractions.

Midds are not a worthless by-product. In fact, it would be a shame not to use them.

Eleanor M Kellon, VMD

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Avoiding Hay Belly

“Hay belly” refers to distention of the abdomen. When viewed from the front, the horse looks pregnant. However, it is not caused by hay per se. A horse can eat very large amounts of hay and still look trim.

As a rule, when viewed from the front the abdomen of a nonpregnant horse should not protrude wider than their shoulders.

A common cause, especially in young horses, is a heavy parasite load in the intestines. In broodmares and older horses with uncontrolled Cushing’s disease (PPID) it is caused by weak muscles in the abdominal wall.  Otherwise, it’s caused by poor fermentation.

The distention is from excessive fluid and gas. The usual cause of this is poor quality hay with excessive amounts of cellulose (part of acid detergent fiber – ADF) and lignin. These hays are overly mature and border on straw. Stems are thick and woody and/or large amount of stem compared to leaf.

Another cause is disruption of the microorganisms in the bowel. This may accompany poor quality hay because there is not enough fermentable material to support good populations of organisms.  Free fecal water may accompany it. It can be a consequence of the drop in diversity of the microbiome that accompanies aging. Insufficient protein can also cause problems since the organisms need a nitrogen source just like the horse does.

The check list for avoiding or dealing with hay belly includes:

  • Deworm the horse with a broad spectrum dewormer with activity against tapeworms
  • Talk to your vet about advisability of PPID testing
  • Switch to a high quality hay that is soft and pliable
  • Feed 8 oz/day of premoistened psyllium husk fiber as a prebiotic and to help regulate fluid content in the bowel
  • Feed a probiotic with high digestive enzyme activity including cellulase
  • Regular light exercise to improve tone of the abdominal wall and improve intestinal function

Feeding less hay is not the solution to a hay belly. High quality hay and supporting good fermentation is.

Eleanor Kellon, VMD


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The Facts About Feeding Straw

Straw is often recommended as an alternative to hay in a variety of scenarios – hay shortage, for weight loss, to decrease sugar/starch in the diet or simply to give the horse something to chew on for longer periods without increasing calorie intake. Straw is an especially common recommendation for feeding donkeys.

Straw is the dead stalks of grain plants, cut after the grain has been harvested. The plants are allowed to die and dry out before harvesting to reduce moisture in the grain.  In some areas the plants are sprayed with glyphosate to hasten their death and drying. This is a very different scenario from harvesting hay which is done when the grasses are still alive and green, at a nutritional peak.

The major reason most people feed straw rather than hay is to reduce the calories but there really is not that much difference – 0.789 Mcal/lb on average versus 0.913 Mcal/lb for grass hay which is a 14% drop. (Dairy One Feed Composition Database).  If you are already feeding a mature hay or one chosen for low sugar and starch levels, the difference is even less since they typically run about 0.850 Mcal/lb with straw then offering only a 7% reduction in calories.

Straw isn’t necessarily safe from a sugar and starch standpoint either. Sugar as high as 6.2% has been reported and starch up to 4.3%.  Straws with a large amount of grain left in the seed heads will be even higher.

There are significant differences in the fiber fractions – not in a good way. ADF and NDF are very high, making straw more difficult to ferment which may result in “hay belly” and diarrhea or free fecal water, in older horses especially.

Protein is also severely deficient, averaging 5.3% in straw versus 10.9% in hay, necessitating protein supplementation. Mineral levels are similar, except for lower average phosphorus and magnesium, but may be less available because of binding to the higher fiber fractions.

Straws have virtually no vitamin value. Because they are difficult to ferment, they are poor support for the microorganisms which would normally produce B vitamins for the horse.  To top it off, there is a higher risk of toxic nitrate levels in straw .

In summary, there is a small reduction in calories but a much higher loss of protein, vitamins and fermentability compared to feeding hay. With all the supplementing you will have to do, including for donkeys, you won’t save any money and analyzing for nitrates is advisable. You are better off investing in slow feeder nets and feeding a nutritionally appropriate hay.

Eleanor Kellon, VMD



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Current Status of the DCM Dog Food Scare

If you have a horse you probably have a dog and have been anxiously following this issue.

Back in 2018 when the scare about grain free dog foods causing dilated cardiomyopathy  started, I wrote that it was at best highly premature and ignored genetic factors, early reports linking it to mainstream, big name dog foods and the role of other key nutrients .

There is strong evidence of a genetic link to DCM in Golden Retrievers and the breed likely has a higher taurine requirement.

In 2019, the FDA went so far as to release the names of specific dog food brands it was investigating well in advance of any solid information to prove they were actually causing a problem.

The initial concerns seriously hurt the grain-free dog manufacturers but the tide has inexorably been turning away from focus on the food to a recognition that “It’s complicated”. .

That’s not to say nutrition isn’t important in heart health – it definitely is. The heart is the hardest working muscle with unique nutritional requirements, including for the amino acids L-taurine and L-carnitine.  These were abundant in the ancestral carnivore diet of meat and organs but are completely absent from all the plant based materials and grains in common dog foods.

Dogs have pathways for manufacturing L-taurine and L-carnitine from L-lysine and L-methionine in the diet. However, those latter two amino acids are commonly deficient in plant-based protein.

To further complicate the situation, high heat processing can damage or destroy critical amino acids like lysine and taurine even in meat based ingredients.  High fiber foods like beet pulp can interfere with normal recycling of L-taurine by reabsorption of bile (bile is taurine based). Other conservation methods like reabsorption of taurine from fluid filtered in the kidneys may vary by breed.

The complexity of the issues involved has essentially left us knowing nothing more than was known in 2018 when this whole thing started. Until there is more information on nutrient requirements down to the breed level and the effects of various processing methods on digestibility, we are back at square one. If you are not feeding your dog like a carnivore it is wise to supplement key nutrients that may or may not be adequately available from the “nutritionally complete” dog food.

Eleanor Kellon, VMD


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Winter Hoof Pain

Frozen and lumpy ground can make any horse hesitant and short-strided. This is something different.

Cold temperatures can trigger severe hoof pain in some horses – Plan ahead to mitigate this

Most horses are energized by cooler weather, bucking and playing exuberantly, but for  some temperature drops mean the temporary onset of relentless hoof pain. Thresholds vary by the individual but the onset can appear even with modest drops like 40 F (4.4 C) and it quickly disappears when temps rise above the threshold.

The syndrome is sometimes called “winter laminitis” because of the severity of signs and reluctance to move but there is no evidence of inflammation and typically no radiographic changes. The cause actually seems to be a failure of the hoof to effectively respond to cold induced changes in circulation.

Cold weather normally reduces blood flow to the limbs and hooves, which is why feet grow more slowly in winter. The hoof has a rich network of arteriovenous shunts, which are pathways for blood to be shunted away from the tissues and returned directly to the veins and from there to the body. Cold causes a reflexic opening of these shunts to quickly divert blood back to the core and preserve body heat in cold weather.

In horses not bothered by the cold, homeostatic mechanisms will periodically close off the shunts and perfuse the tissues to prevent oxygen and nutrient levels from getting too low. In horses with cold induced hoof pain, this process appears to fail and the tissues are not adequately perfused. Support for this being the cause comes from the response to efforts to support circulation.

Jiaogulan is a Chinese herb with a well documented ability to stimulate the production of nitric acid by the endogenous nitric oxide synthase enzymes (eNOS) located inside blood vessels.  Nitric oxide is a potent vasodilator in the body. The vasodilating effects of Jiaogulan can be further supported by providing arginine, citrulline and folic acid – the raw materials needed to generate nitric oxide.

Susceptible horses can be further supported by blanketing them to conserve body heat and the use of leg wraps. Lined shipping wraps work particularly well because they are easy to apply and won’t slip down, which can constrict the tendons. Felt lined boots or the use of wool socks over the feet before applying boots completes the picture. Another advantage of using shipping boots is they typically extend down to cover the heels and coronary bands, which keeps snow and rain out of the boots.

Cold induced hoof pain is temporary but a significant issue for your horse. Fortunately, it can usually be successfully managed.

Eleanor Kellon, VMD

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Can You Tell Good Hay By Looking At It?

Hay analysis is the only way to get nutritional details but appearance does yield some useful information.  Just the type of hay is a helpful start.  Legumes (clover, peanut, alfalfa) are always high protein and calcium.  Bermuda will be low protein unless fertilized.  Ryegrass and grain hays tend toward high sugar, plus starch in the grain hays.  Contrary to popular belief, there is no type of grass hay guaranteed to be low sugar and starch although some, like Teff, are often low.

Hay is the bulk of your horse’s diet – choose wisely

Seed heads are the easiest way to identify a grass hay. Timothy’s fuzzy, long seed heads look like a green or beige caterpillar.  Bermudagrass seed heads resemble the spokes of an inside-out umbrella. Teff grass seed heads are a bouquet of long, graceful sprays with the multiple thin straight strands having a chain of individual seeds.  If you don’t know what to look for, take a sample of the hay, including seed heads, to your local agricultural extension office.

Ideally you want an obvious green color.  Color isn’t necessarily a deal-breaker if you know why the hay is yellowed instead of green. It may be old, sun bleached or rained on after cutting.  All yellowed hay is low in the vitamin A precursor carotene.  If only sun-bleached, the inner layers will still be green and loss is minimal. If old and yellow throughout it will also be very dry and the leaf/blade portion more likely to crumble and be lost, greatly reducing nutritional value. Rained on hay will have lower sugar, thus lower calories, and lower (but likely still adequate) potassium.

Seed heads also yield clues to likely calorie and sugar/starch content.  If no seed heads or they are very green and firm, seed has not yet set and calories, sugar/starch will be higher in the hay. Seed heads that are tan but still contain seeds will contribute to the starch and overall caloric value of the hay, while old empty seed heads belong to very mature grasses with likely lowest sugar/starch, calories and protein.  You want to see a large proportion of leaf/blade  material compared to stiff stems.

Bales that feel unusually heavy for their size are often high moisture, moldy or contain stones/dirt. Always open a few bales even if you have to buy them first.  Never buy hay that feels moist or warm on the inside.  It’s going to mold.  It should have a fresh, “sweet” hay aroma.  No smell or an off odor indicates molding or very old hay.  When you open a bale, there should be no puff of fine dust. This may be dirt or it may be molding. You don’t want either. Obvious molding, chunks of dirt, stones or other foreign material, and presence of weeds are all reasons not to purchase.

If a hay has passed the important visual assessment you will still need hay analysis to get in-depth nutritional information.  Calories (DE – digestible energy), crude protein and important mineral levels are all part of the analysis.  Sugar and starch levels can be obtained.  Armed with the analysis you will be able to select the appropriate vitamin, mineral and amino acid supplement.

Hay (or pasture) is by far the major part of most equine diets.  The critical information you need to identify and correct deficiencies and/or imbalances can only be obtained from an analysis.

Eleanor Kellon, VMD

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Dewormer Effects on the Microbiome

We’re all familiar with the threats posed by parasite infections and the need to control them but the microbiome may be the victim of  friendly fire.

Deworming is necessary but may impact the microbiome

Dewormer drugs  (anthelminthics) are not antibiotics and do not directly harm the microorganisms in the gut but removing resident parasites may have a downstream effect on the microbiome.

Formal research on this issue has turned up some contradictory results.  Crotch-Harvey et al 2018 studied horses on a spring pasture. Five horses with small strongyle fecal egg counts over 200 were treated with fenbendazole while five others with lower counts were not.  They found no significant changes in the bacterial or protozoal populations as a result of the deworming.

However,  Walsh et al 2019 reported a very different story. They studied yearling and adult horses on two different premises that had a positive ELISA blood test for encysted small strongyles and positive fecal egg counts, as high as 2050 eggs/gram.  They were dewormed with either moxidectin or fenbendazole. They measured serum fibrinogen as a marker of inflammation and fecal albumin as a measure of disruption of the  intestinal mucosa. They found:

“Overall, the results demonstrate that removal of helminths through anthelmintic treatment induces a change in the faecal microbiota, including decreased alpha and beta diversity at Day 7 post-treatment, which mostly resolved by Day 14. This change coincided with local and systemic inflammatory responses, as indicated by serum fibrinogen and faecal albumin measurements. “

The same things were  found with both dewormers. The difference between the two studies was likely due to the heavier parasite burden in the second study.  The removal of the adult small strongyles probably triggered emergence of encysted forms in the fenbendazole group and a reaction to killed encysted forms would occur in the moxidectin group. However, the authors also discussed that when there is an established population of parasites there are going to be interactions between them and the microbiome which are disrupted when the horse is dewormed.

 None of the horses in this study showed signs of gastrointestinal upset from the deworming but the sample was relatively small and it’s well known that some horses do have reactions.  The findings of this study suggest it would be wise to support the microbiome and health of the intestinal lining when deworming your horse.

A probiotic product with both beneficial bacterial and yeast organisms is a good start.  The nutrition of intestinal cells is highly dependent on the supply of the amino acid L-glutamine. Glutamine also plays an important role in the immune health of the intestinal tract and assists in maintaining a healthful balance in the populations of microorganisms . Use 20 grams/day. Start supplementation a few days before deworming and continue for 2 to 3 weeks.

 Eleanor Kellon, VMD


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Calcium and Your Horse

Appreciation for the importance of nutrition lies in understanding the role of nutrients in body processes.

Calcium is an important structural mineral. Most of the body’s calcium is incorporated into bone and teeth where calcium in a crystalline structure makes these tissues very rigid and strong. Calcium also has multiple other roles. All complete horse vitamin and mineral supplements include calcium. You can also supplement your horse through food high in calcium or calcium supplements.

Alfalfa is an excellent source of calcium, about 5 grams per pound

Although it is only a tiny fraction of the total body calcium, free ionized calcium, Ca++, in the blood and tissues also has key functions. Ionized calcium is so important to how the body functions that it is one of very few minerals which has hormonal regulation of high and low levels. It’s the only mineral where both upper and lower possible concentrations must appear on feeds by law.

One job you may not realize is coagulation – blood clotting.  Along with vitamin K, calcium is a critical factor for the formation of clots to stop bleeding.

Calcium is the activator for release of chemicals from nerve endings, for constriction of arteries in regulation of blood pressure and calcium release from storage structures inside muscle cells causes muscular contraction.  The swimming of sperm requires calcium. Calcium is also needed for the release of insulin from storage areas in the pancreatic cells.

Other minerals work with calcium or are needed to balance out its effects. These include phosphorus, potassium and magnesium. All must be present in correct concentrations.

The average size adult horse at maintenance requires around 20 grams/day of calcium. Growing, pregnant and lactating horses have much higher requirements.  The best natural sources of calcium are alfalfa, clover, and beet pulp. Uckele calcium, Equi-Cal, incorporates three high available calcium sources with alfalfa in a palatable base for easy supplementation. Always consult your veterinarian or nutritionist for advice on how much to add.

Eleanor Kellon, VMD


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Truths, Half-Truths and Misconceptions about Grain

Domesticated horses have been fed grain since at least the time of the ancient Romans but in the last 20 years this has been questioned. As with most controversial subjects, it has generated many viewpoints that are factual, totally false or something in between.


Grain causes poor hoof quality.  This is a very common belief but has very little to support it. Poor quality can mean anything from cracks to thrush to poor white line connections.  Truth is that grain per se cannot cause any of these things.  If related to dietary mineral imbalance, it is that imbalance that is to blame, not the grain per se. Forages also have imbalances.

Grain causes laminitis.  There is more truth to this specific claim, but only in some scenarios.  If a horse receives an amount of grain large enough to spill over into the large intestine and cause a severe acidosis with intestinal wall damage, laminitis may result from leakage of bacterial products into the blood.  This does not happen with commonly fed amounts of grain.  Horses that are insulin resistant can also become laminitic when fed grain because of the very high levels of insulin it causes in those horses – a different mechanism from grain overload laminitis.  Normal horses do not develop these extremely high insulin levels when fed grain.

Grain Causes Hind Gut Acidity and Damage. This is related to the grain causing laminitis issue.  It’s a matter of amount fed. The digestive tract is designed to withstand considerable variation in pH/acidity before tissue damage occurs. Willard et al did a study where they fed horses either 8 kg of hay or 6 kg (13.2 pounds) of sweet feed and directly measured the pH in the cecum every hour for 12 hours. The pH in the cecum was only significantly lower at the 4, 5 and 6 hour time points but never dropped below 6 while the critical pH for causing even irritation is below 5.5.  The only consequences noted were increased wood chewing and manure eating – correlating with greatly reduced time spent eating. To completely avoid any pH disruption in the hind gut it has been suggested that meals be limited to 1 to 2 g of starch per kg of bodyweight per feeding which would be 2.5 to 5 pounds of plain oats for a 1000 lb horse.

Feeding grain causes insulin resistance.  When horses are fed high grain diets, intravenous testing shows insulin is not as effective in lowering glucose loads. However, their ability to clear glucose from the blood is still normal.  This is not the same thing as the extremely high insulins that develop in horses with metabolic syndrome and it is not associated with laminitis. Metabolic syndrome has its roots in genetics, not diet.

Horses don’t need grain.  For most horses, this is true and they may often be calmer without it.  However, the harder the horse works the more likely it is that some grain will be required to keep good levels of glycogen in the muscle.  Failure to progress in training, poor endurance and fatigue are signs the horse may need some grain.

Unless your horse needs grain to support muscle when working, or in some cases to support growth, there is nothing wrong with not feeding it. Just don’t make the change based on unjustified fears.

Eleanor M Kellon ,VMD

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