An Equine Methionine Deficiency Crisis is Looming

I’ve written about soil sulfur and methionine deficiency often. Everything I’m seeing says it’s getting worse.

Methionine for hooves and a whole lot more

Methionine is an essential amino acid, meaning horses must get it from their diet. It is critical in protein synthesis since many proteins start with methionine and without it synthesis will stop.

Methionine is the king of the sulfur-containing amino acids which give strength to hair, hoof horn, skin and tendons/ligaments. It is the precursor for SAM-e, a mood stabilizer, and the major antioxidant glutathione.

Methionine is a methyl donor required for the synthesis of L-creatine and L-carnosine. These compounds are critical to muscle function and athletic performance.

Soybean, peas and beet pulp are poor methionine sources. Historically, grains, brans and other seed meals were adequate sources. Hays easily met the 0.2% sulfur content most authorities recommend to support production of good levels of sulfur-containing amino acids. This is changing.

I am increasingly seeing hay analyses with sulfur below 0.2%, even below 0.1%. This means soil levels are low so grains will also be affected. What’s going on?

A positive result of the industrial revolution and burning of fossil fuels was the release of sulfur into the atmosphere. Sulfur is essential for plants and became so abundant that farmers no longer needed to add it to fertilizers. However, with the appearance of pollution controls in the late 1980s and 1990s, sulfur emissions were curtailed. Cleaner, but soil sulfur has suffered.

It wouldn’t surprise me if methionine comes to rival lysine as the most commonly deficient amino acid. If you analyze your hay, make sure it includes sulfur. Otherwise, methionine should be supplemented as routinely as lysine at about half the lysine level, such as in Tri Amino, the original essential amino acid supplement which was ahead of its time and more important today than ever.

Very severe methionine deficiencies can cause poor muscling and stark coats which do not respond to mineral balancing. Brittle hooves with superficial or deep cracks are also common. In these cases, methionine supplementation at 10 grams/day or more is needed.

Eleanor Kellon, VMD

Posted in Equine Nutrition | 2 Comments

Fiber as a Food for Horses

Horses can derive significant calories from things that are indigestible for us.

You’ve heard your horse’s intestinal tract referred to as a furnace.  Obviously that’s not literally what happens.  It is where bacterial fermentation takes place.  Fermentation reactions produce cheese and your favorite adult beverage but that’s not what is going on either.

One of the attention grabbing factoids they threw at us early in veterinary school was that cows could survive by fermenting nothing but newspaper. They won’t be healthy for very long doing this but the point was that newspaper can be converted to calories to sustain life.  This hasn’t been tried with horses but all would agree that we couldn’t survive on hay the way horses do.

Fermentation is the enzymatic breakdown of a substance with the enzymes in this case coming from bacteria, yeast and protozoa.  Cellulose, hemicellulose, complex plant carbohydrates, fructans and soluble fibers like pectin and betaglucans are all indigestible by the horse’s digestive enzymes but can be fermented in the large intestine.  The organisms use some of the energy contained in these food fractions for themselves and what is left over, the products of fermentation, are readily absorbed into the blood stream and are what the horse uses as energy sources.

The products of fiber fermentation are primarily acetate, butyrate and propionate.  Simple sugars, starch and fructans also produce lactate.  These fermentation products can account for 60% or more of the calories absorbed by the horse.

Most people have a misguided poor opinion of lactate.  It is an important fuel that can be converted to pyruvate and burned for energy, or converted into glucose or glycogen.  Acetate is a very efficient energy source, ready as-is to enter the mitochondria to be burned.  Acetate also spares glucose which can then be used for other things like replacing glycogen stores.  Acetate is the major fermentation product of hay with even larger yields from beet pulp or soybean hulls.

If butyrate reaches the liver it can be converted to fat but most of it is used by the intestinal lining cells.  Propionate, also produced in smaller amounts than acetate, can be converted to glucose.

Now if someone asks you why horses don’t get drunk from fermenting their  food (don’t laugh, I’ve seen a claim that they can!), you’ll know why.

Eleanor Kellon, VMD

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Beware Supplemental Iron

It’s common knowledge that horses with anemia and performance horses should get iron supplements to build their blood – right? Wrong!

Iron deficiency anemia does not exist in adult horses

Close to 70% of the body’s active (not stored) iron is in the red blood cell pigment hemoglobin where it functions to bind oxygen from the lungs and carry it to the tissues. Iron is also the active binding element of myoglobin, the pigment that makes muscle red and acts to temporarily store oxygen in muscle and deliver it to the aerobic metabolic pathways for generation of energy. Iron is an indispensable component of hundreds of other proteins and enzymes in the body.

The body also takes advantage of iron’s high reactivity to shuttle free electrons in the chain reaction that generates energy from foods in the form of ATP. A few antioxidant enzymes also use iron and iron is used in body systems that detect dangerously low levels of oxygen.

However, iron’s free and easy contribution in free radical reactions can have a black side. In white blood cells it is used to generate free radicals which are used to destroy invading organisms. When unchecked, that same capacity to generate free radicals can easily damage tissues.

While horses can be anemic for a variety of reasons, iron deficiency is not one of them. Except for foals raised in stalls with no access to dirt, iron deficiency anemia has never been found in a horse.

On the other hand, iron overload as evidenced by livers turned black with extra iron is a fairly common finding on necropsy. In a study of horses at a slaughter house, 28% were found to be iron overloaded. Two studies have found iron overload is common in horses with insulin resistance. The common problem of coat bleaching is associated with high iron and/or low zinc and copper.

Before considering an iron supplement or injection for your horse, always have iron status checked by blood level of ferritin. This can only be done at the Comparative Hematology laboratory at Kansas State University.

Iron overload is a well recognized problem in people with a genetic predisposition to overabsorb iron as well as those with needs for frequent transfusions that release iron when the red cells die. Iron overload from the diet has also been documented from a host of animals kept in captivity, from birds to rhinoceros to lemurs and even dolphins.

Because free iron is so dangerous to the body, there is an intricate system to keep it under control. Iron can be absorbed through the gaps between intestinal cells, a process that is increased in the presence of products of fermentation of hay/forage. Otherwise, iron is absorbed into intestinal lining cells in the small intestine. From there, it’s release is controlled by hormones/regulators that can block movement out of the cell and control the electrical charge of the iron, which in turn determines if it can be picked up by its carrier protein, transferrin.

Hormones also regulate how much can be taken up by the body’s cells. Any excess is stored bound to the proteins ferritin or hemosiderin.

Iron overload probably occurs because the unregulated pathway of absorption between cells is very active in horses. Once inside the body, there is no pathway for excreting excess. It has also been shown in insulin resistant humans that this disorder increases iron absorption, and the high iron worsens the IR in a vicious cycle.

The bottom line here is that supplementing iron is not something you need to be worrying about, even for anemic horses, and for IR horses it is wise to restrict iron as much as possible.

Eleanor M Kellon, VMD

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Exercise and the Metabolic Horse

Much has been written about the diet for horses with metabolic syndrome and elevated insulin but the most effective control measure is exercise.

Exercise is the best insulin-buster for the horse

A very common story in the Arabian world is a horse that has been in active endurance training and racing is taken out of work and within a month has ballooned in weight and become laminitic. Part of the problem in some cases is failure to drop the calorie intake but the major factor here is lack of exercise.

Diet is very important, even with working horses, but it can’t compare to the benefits of exercise. Exercise flips a switch in the muscle cells that increases their uptake of glucose by pathways which do not require insulin. This greatly reduces the work that insulin has to do and insulin levels drop.

A 2019 study compared weight loss and insulin sensitivity in two groups of obese horses. One had calories restricted to 85% of their requirements while the other was exercised at a level that would burn the same amount of calories. Only the exercised horses had improvements in neck crest and some tests of insulin sensitivity over the 4 week study.

Exercise will not eliminate the need for diet control. Depending on the individual and level of exercise, some horses will be able to perform on the same restricted sugar and starch as they have when not working. Others may need diet liberalized.

Signs the horse needs a more liberal diet include early fatigue, failure to advance in training and possible muscle cramping. Addition of 30 to 60 minutes of pasture grazing or a small feeding of oats, fed only immediately after exercise, is often all that is needed. On the Equine Cushings and Insulin Resistance group we have guidelines for management of horses in work.

Evolution engineered the horse to move; a lot. Failure to provide sufficient exercise is one factor behind metabolic disorders. As with diet, this is completely within your power to control so make the effort and help your horse with exercise.

Eleanor Kellon, VMD

Posted in Equine Nutrition | 4 Comments

Nutrition in Late Pregnancy

Can you just increase the amounts you are feeding but basically feed the prepregnancy diet and maintain the mare’s weight in pregnancy?  Yes – her amount of fat anyway.  Can you get a live, full term foal?  Yes.  Are you risking problems?  Yes, absolutely.



Your average size horse mare is about to deliver 100+ pounds of newly formed skin, bone, blood, muscle and organs along with another 150+ pounds of membranes and fluids formed for support of the developing foal.  She didn’t build all that from air.

All successful species evolve with the ability to survive difficult times.  If a pregnant mare is deprived of a nutrient her developing foal needs, her body will sacrifice from its own supply to support the fetus.  Fat breaks down for calories, muscle for amino acids, bone and other storage sites like liver for minerals.  The foal will be born alive but her weakened condition impairs fertility, immunity and her ability to produce adequate milk. There are long term effects like risk of arterial rupture from copper deficiency.

If the mare still can’t fully provide for the foal by robbing her body, it can be born with issues like white muscle disease from selenium deficiency, weakness and goiter in iodine deficiency, contracted tendons or OCD lesions from copper deficiency, skeletal abnormalities in vitamin A deficiency.  More common than full blown deficiencies are foals born small, weak and spindly rather than the vigorous and robust foals of a properly fed mare.

In late pregnancy, calorie needs increase by 28% but protein needs by 100% and minerals 80%.  A diet formulated adequately for an adult nonpregnant horse won’t cut it.  Mare and Foal feeds are not necessarily the answer either.  Even at 14 to 16% protein they will provide only about 1/3 of what is needed.  Minerals add up better but still fall short and both the protein and mineral requirements still needed are less likely to be met because of greatly decreased hay fed when grains are given at their maximum recommended amounts. The pregnant uterus also takes up a lot of room.

To determine exactly what your mare needs, and how much, you should consult a professional. In general though, the answer lies in concentrated protein/mineral supplements with 25 to 30% protein, lysine 2+%, calcium 4+% and copper around 300 ppm with other minerals in correct balance.

When you see a truly robust foal you’ll know you have it right. There’s no comparison.

Eleanor Kellon, VMD

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Selecting Treats

There are many behavioral and safety reasons not to give your horse treats but for those who can’t resist, this is for you. 

If you must give treats, at least do no harm.

This feral horse skull shows remarkably clean teeth.

In choosing treats for your horse, please avoid the temptation to go with things that remind you of your grandmother’s kitchen or the pastry wall at Starbuck’s.  Cookies, buns, biscuits and muffins are not for horses.  While the horse is equipped to appreciate sweetness to help guide him to calorie rich plant material, feeding high sugar items is not good for oral health.  The fact he will eat fries, creme donuts or peanut butter and jelly on white bread then wash it down with Coke or Pepsi doesn’t mean you should let him do it!

The bacterial population in the mouth depends on what is in there to feed it. Sugar or starch rich foods support bacteria which thrive on these carbohydrates and release acid which damages the teeth and inflames gums. These are common issues in domestic animals and nonexistent in feral ones.

If purchasing treats, you have to be careful to actually read the ingredients list. One treat that calls itself  natural,  crunchy and carrot has wheat as the first ingredient.  It also contains wheat midds, molasses, corn and a long list of inorganic minerals.  The name doesn’t necessarily reflect what’s in them.

Why not keep it truly natural, simple and good for the horse at the same time?  There are many things the horse would appreciate eating that don’t belong in a candy dish or cookie jar.  Some you will have thought of  – others not so much.

To our senses they have all the appeal of driveway gravel but split dried green peas are relished by most horses.  I don’t know how they can tell it’s even something edible but horses will readily snatch up the rock hard little green peas. Avoid dried beans though. They interfere with digestion unless cooked.

Another one you would probably not think of is cubed Kudzu root. This is available inexpensively from bulk herbal suppliers.  The little cubes look like cork and have no human detectable aroma but the horses eat them right down. They are loaded with antioxidant bioflavanoids.  Speaking of crunchy antioxidants, many horses love Rose Hips as well.

Oldies but goodies on the list of things you can safely carry in your pockets are peanuts, sunflower seeds, cashews, almonds, pumpkin seeds, carrots and celery.  Very healthful but more of a challenge to carry around are grapes, prunes, bananas and berries of all kinds.

Last but far from least is a simple handful of freshly picked grass and/or clover. There’s really nothing they like more.  If you are going for the convenience of a bagged treat, look no further than alfalfa or grass hay as the base.  If you want to  mix up the flavor a bit, apple,  cherry, banana, fenugreek and peppermint are all favorites.  You can get the appeal of grains, without the high starch, from Brewers or Distillers dried grains which are grains with the starch fermented out of them.  Avoid molasses, dextrose or maltodextrin (all sugars) in favor of the natural herbal sweetness of Stevia which has been proven to not cause an insulin rise in horses.

Eleanor Kellon, VMD

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The Heart of Laminitis Care

I am personally very involved with medical causes but this is about a central issue for all laminitis cases – the trim.

Medications, diet and supplements can’t make up for an inappropriate laminitis trim

Whether the horse has true rotation – coffin bone/P3 out of alignment with P2 – or capsular rotation – hoof wall pushed away from P3 by swelling or laminar wedge – the goal of trimming is realignment.

A realigning trim also corrects for the elevated palmar angle (angle the bottom of the coffin bone makes with the ground) seen in horses with true rotation. Reduced growth at the toe compared to heel can also result in this problem in any laminitis horse.

It’s that simple and the realigning trim is as important today as it was when I learned it 45 years ago. Some things don’t change. The physiologically correct alignment between coffin bone, hoof wall and ground is one of them.

Many different shoeing and hoof appliance options have been suggested over the years. The one thing they all have in common is starting with a realigning trim. A major reason for failure of all these options is skipping the realigning trim or failing to maintain it.

In almost 25 years of dealing with hundreds of laminitis cases on the Equine Cushings and Insulin Resistance group, the most difficult ones we get are those where the correct trim was not instituted or maintained.

If all laminitic horses would have radiographs done early and trim corrections as needed from the beginning we would have far fewer treatment failures.

Eleanor Kellon, VMD

Posted in Equine Nutrition | 6 Comments

Hoof Care in Winter

Winter weather puts a strain on all body tissues with special challenges for the hooves.

Don’t skimp on hoof care over the winter

Cold weather reduces blood flow to the extremities and unless your horse is doing a lot of exercising hoof growth is going to slow considerably. This means problems like cracks or chips won’t be growing out. If the horse is shod, nail holes will enlarge and shoes become loose before enough foot has grown for a reset.

Pulling the shoes for the winter and putting a good roll on the hoof wall both protects the wall and encourages growth by improving circulation in the hoof. If you need a further boost, try Jiaogulan.

The combination of cold, low humidity and decreased circulation can lead to a dry hoof wall and heel cracks. For the wall and sole, my preferred dressing is a light coat of pine tar. For coronary band and heels/bulbs, simple is best – petroleum jelly or Cornhusker’s lotion. If painful cracks develop, nothing beats Zim’s Crack Creme (great for split skin on hands too).

For inside out support, maintain a mineral balanced diet with adequate methionine. Vitamin A supplementation should be 20,000 to 40,000 IU/day. Extra fat also helps the tissues. Simply curing hay reduces the fat intake an average of 200 mL/day (about 7 ounces) . A healthy hoof wall has a high concentration of fats and fat-derived waxes.

Want to pamper and treat those hooves at the same time? Put a small ball of Pine Tar hoof packing , one for each hoof, between the leaves of a folded piece of wax paper and microwave for about 10 seconds. Flatten then apply to the soles.

Eleanor Kellon, VMD

Posted in Equine Nutrition | 2 Comments

Electrolytes in Winter

Horses don’t need electrolytes in winter – right? Wrong.

Working horses sweat in winter too.

Electrolytes are minerals that exist in the body in an electrically charged form. The major ones are sodium, potassium, chloride and bicarbonate. The body makes its own bicarbonate but the others must come from the diet.

Sweat is a major avenue of loss, including in winter. Very dry air means easy evaporation and loss may be underestimated.

There are also losses that have nothing to do with sweating. Just standing around they are 10 grams/day for sodium, 25 grams/day potassium and 40 grams of chloride for an 1100 pound horse.

Electrolytes are needed by all cells but play especially important roles in the nervous system, heart, skeletal muscles, kidneys and digestive tract. They are critical to maintaining normal fluid levels in and around cells as well as normal water intake. Sodium is particularly important for thirst.

Unless the horse is working heavily and on minimal forage, potassium needs are met by the diet. Sodium is essentially absent from their food. Hay can be a decent source of chloride but levels vary widely.

The solution to sodium and chloride is simple – plain salt. An ounce of salt/day is a reasonable goal for average size horses. Add to meals or sprinkle onto moistened hay. This one simple addition goes a long way in preventing impaction.

It’s best to feed salt this way but fine to also offer it free choice. Coarse loose salt is ideal but blocks work for many horses. It’s a myth horses can’t get enough salt from a block because they don’t have rough tongues. It’s melting from saliva that lets them get salt from a block. Cows don’t have tongues rough enough to cut through a salt block!

Eleanor Kellon, VMD

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Alfalfa and Equine Gastric Ulcers

Alfalfa has a reputation of helping treat or prevent gastric ulcers in horses but where is the proof?

The evidence is weak for alfalfa being better than grass hay or pasture in horses with EGUS

EGUS is equine gastric ulcer syndrome. Gastric erosions have been found in horses of all ages, breeds and disciplines. Even 70% of horses turned out to pasture may have ulcers.

The difference between anecdotal evidence (people’s experience/stories) and research is that research strives to eliminate or control other factors that could influence the outcome. Let’s see what the research has to say about alfalfa and EGUS:

  • Vondran et al 2016. Alfalfa chaff actually associated with more ulcers at the pylorus. No difference between alfalfa chaff, alfalfa pellets and grass hay at other locations.
  • Nadeau et al 2000. Alfalfa + grain buffered stomach acid better and was associated with less severe EGUS than a bromegrass only diet.
  • Bauerlein et al 2019 found no benefit or harm feeding alfalfa versus meadow hay.
  • Lybbert et al 2007 (AAEP only, never published) alfalfa + grain resulted in fewer ulcers than grass hay + grain.
  • Juliland et al 2021. Trotters in very heavy work on high grain rations. Replacing 50% of the grain with alfalfa pellets made no difference in ulcer score.

Not very convincing – and the reasons proposed for alfalfa being good for EGUS don’t hold water.

The high calcium and magnesium in alfalfa are said to buffer stomach acid. This probably comes from the fact that salts of calcium or magnesium, like carbonates or oxides, can buffer stomach acid. However, it’s the carbonate or oxide portion that does the buffering, which is combining with H+ ions to neutralize them. Calcium and magnesium themselves also have positive charges. They can’t buffer.

It is true that protein can buffer stomach acid. The carboxyl and amino acid groups liberated as protein breaks down can bind H+. However, protein in alfalfa is not terribly high even compared to seed meals and protein also eventually stimulates acid secretion during digestion.

EGUS can be effectively moderated and treated but don’t count on alfalfa to do it.

Eleanor Kellon, VMD

Posted in Equine Nutrition | 3 Comments