Amino Acid Supplements for Horses : When to Feed More Protein?

By Alberto Roy

Updated on:

Is your steed obtaining a balanced range of vital and also non-essential amino acids from their feeding program? Amino Acid Supplements for Horses are recommended by most of us. Your steed needs sufficient amino acids in their diet regimen to make healthy proteins.

Proteins are complicated particles needed for virtually every physical function, including muscle contraction and neural communication.

They additionally regulate the metabolism of sugars, fats, immune reactions, as well as various other functions.

Steeds can experience a vast array of symptoms from low degrees of protein or amino acids in their diet regimen.

Amino Acid Supplements for Horses

  • Loss of muscle mass
  • Poor growth
  • Slow recovery from illness
  • Poor performance
  • Rough coat
  • Weak hooves

These signs and symptoms are not only referring to healthy protein scarcities and also can additionally be created when power requirements aren’t met or when there are nutrition lack.

Amino Acid Supplements for Horses 3

A diet plan regimen evaluation that includes an examination of hay is one of the most effective method to create if your steed is getting ample amino acids with their feeding program.

Does Your Horse Need A Lot More Amino Acids? Requirements?

Pets that are expanding young are extra vulnerable to shortage in amino acids because they are much more in need for healthy protein in order to assist in their fast development.

Protein needs are additionally higher in mares in the late stages of pregnancy along with in the beginning of lactation to help sustain the growth of the fetus and also optimal milk production.

Just like various other animals, can not conserve the excess amino acids to be utilized in the future. Healthy protein is called for to be frequently supplied through diet regimen.

But, eating too much protein isn’t only costly as well as can place unnecessary tension on the liver as well as kidneys.

Horses of senior age that are in intense exercise as well as those who have metabolic issues should have their healthy protein intake kept an eye on to stop surplus.

Amino Acid Supplements for Horses 5

Certain amino acid supplements could be beneficial to horses on the occasion that their diet plan is not sufficient in the particular amino acid. Methionine, threonine, and also lysine are the most often lacking amino acids discovered in horse diet plans.

Ensuring that their needs are met will certainly help make certain an ideal healthy protein synthesis for the general well-being of horses.

Essential Amino Acid Supplement with Lysine Methionine Threonine

Three Amigos

  • Optimal protein synthesis
  • Hoof & coat quality
  • Topline development
  • Athletic performance

Amino Acid Nutrition in Horses

If an Equine Nutritional expert regulates proteins in the diet plan of the equine’s diet, what they’re most concerned about is meeting your private amino acid requirements.

Equines don’t absorb intact healthy proteins from their diet regimen. Actually, proteins found in forages, grasses and also grains are gotten into smaller pieces by enzymes within the small intestine.

The numerous amino acids, also called Peptides (brief chains comprising 2 to 3 amino acids) are then taken into blood. They are made use of by all cells in the body to create the protein that steeds require.

Proteins can only be created only if all amino acids remain in area. Otherwise, your body will certainly break down other proteins in order in order to provide the required amino acids which might lead to unfavorable health and wellness impacts.

Types of Amino Acids for Horses

There are 21 amino acids that are made use of to make healthy proteins in horses. These all have a comparable chemical structure, but differ in the plan of atoms in a part of the particle described as the amino acid side chain.

Amino Acid Supplements for Horses 6

Amino acids can be broadly divided into three categories:

Essential: 10 amino acids that must be provided in the diet because they can not be made in the body (endogenously).

Non-essential: Amino acids that can be made from amino acids or other compounds in the body and do not need to be supplied by the diet.

Conditionally essential: Amino acids that might be necessary in the diet because their supply can not keep up with demand under certain circumstances such as rapid growth or illness.

We will consider the features, resources, symptoms of deficiency and also excess and also requirements of each amino acid. We will certainly additionally review the amino acid profiles of different healthy proteins.

If you are thinking about making modifications to your feeding routine Before making any type of modifications to your feeding program, you can send your equine’s diet regimen to us for an evaluation or one of our Equine Nutritionists will aid you in reviewing the requirements of your horse.

Essential Amino Acids Supplements for Horses

The 10 amino acids that must be supplied by the horse’s diet are:

Amino Acid Supplements for Horses 2

  • Lysine
  • Threonine
  • Methionine
  • Tryptophan
  • Leucine
  • Isoleucine
  • Valine
  • Histidine
  • Phenylalanine
  • Arginine

All amino acids vital to life are used to develop proteins. Specific healthy proteins require even more of a particular amino acid to ensure that the healthy protein has the ability to fold into the appropriate form to fulfill its function.

Amino acids might additionally be changed right into various other particles with specific features within the body.

Lysine Amino Acid Supplements for Horses

Lysine is typically considered the first rate limiting amino acid in equine diets. It is the amino acid that is most commonly deficient to the point of limiting protein synthesis in the horse.


  • Is converted to carnitine, a vitamin-like compound that supports key enzymes involved in breaking down fat for energy.
  • Increases calcium levels in the body by increasing calcium absorption and minimizing calcium loss in urine.
  • Is involved in making collagen and elastin, important proteins found in high levels in skin and connective tissue including tendons, ligaments and cartilage.
  • Lysine is a critical component of the muscle proteins actin and myosin that interact to facilitate muscle contraction.
  • Supports the immune system by helping fight viral and bacterial infections.

Sources: Legumes like soybeans and soybean meal are high in lysine. Canola meal can also provide good levels of lysine. We also carry supplements that supply L-lysine alone or in combination with threonine and methionine to supply these limiting amino acids in the correct balance.

Deficiency: Even with adequate protein intake, horses are likely to be low in lysine, especially if they have limited forage or fresh grasses in their diet.

Amino Acid Supplements for Horses 1

Low levels of lysine in the diet can result in a variety of symptoms reflective of suboptimal protein synthesis, including poor exercise performance, muscle loss, rough coat and weak hoof structure.

Excess: Lysine competes with the amino acid arginine for uptake into cells. Very high levels of lysine could interfere with how arginine is used in the body and affect nitric oxide production which influences blood flow. This is unlikely to occur with levels typical in equine diets.

Lysine Amino Acid for Horses


  • Healthy skin & joints
  • Hoof & bone growth
  • Muscle growth
  • Carnitine synthesis

Threonine Amino Acid Supplements for Horses

Threonine is often considered the second most limiting amino acid in equine diets after lysine. Low levels of threonine in the diet can affect gut health and protein synthesis in all cells of the body.


  • Supports gut health and optimal nutrient absorption. It is involved in making mucin proteins which form a protective mucous barrier between the acidic environment of the gut and cells of the stomach and intestine.
  • Is converted to another amino acid called glycine which is required to make creatine, a high energy compound naturally found in muscle tissue.
  • Can be used to make glucose in a process called gluconeogenesis in the liver and can be broken down for energy.
  • Threonine in proteins is often modified through cell signaling networks to change how the protein functions in response to signals from outside the cell.
  • Support a healthy body condition by turning on genes involved in burning fat and turning off genes involved in storing fat.

Amino Acid Supplements for Horses

Sources: Threonine is found in most plant and animal proteins. It is highest in potato and pea proteins, soybean meal and alfalfa. It is low in cereal grains like wheat and oats. We carry threonine as a single ingredient supplement for horses, or in a 5:3:2 ratio with lysine and methionine.

Deficiency: When there are low levels of threonine in the diet, most of this amino acid is used for making mucins in the gut. This causes low levels of threonine in other tissues which could manifest as low energy levels and loss of muscle mass.

Excess: No specific consequences of excess threonine intake have been reported in horses.

Threonine Amino Acid for Horses


  • Gut barrier function
  • Nutrient absorption
  • Collagen & elastin
  • Muscle growth

Methionine Amino Acid Supplements for Horses

Methionine is a sulfur-containing amino acid that can be converted to the non-essential amino acid cysteine. It is also used to make several compounds that have important biological functions in the body.


  • Cysteine, derived from methionine, is important for making keratin proteins found in high levels in hoof and hair. The sulfur in cysteine molecules forms bonds which help give hooves and hair a strong structure.
  • Methionine is converted to s-adenosyl methionine (SAMe) which is a methyl donor involved in regulating gene expression and protein function.
  • Is converted to adenosine, the key component of adenosine triphosphate (ATP), the main energy currency of the cell.
  • Is used to make taurine, an amino acid that is not used for synthesizing proteins but supports cells of the nervous system.
  • Is important for making phosphatidylcholine, a phospholipid found in cell membranes.

Sources: Methionine is high in animal proteins, soybean meal, alfalfa protein and canola meal. It is low in cereal grains and grasses. DL-methionine can be fed as a single ingredient supplement for horses or with lysine and threonine.

Deficiency: Low levels of methionine in the diet can contribute to rough coat and weak hooves because deficiency will result in low sulfur levels.

Excess: No specific consequences of excess methionine intake have been reported in horses. Experiments in rats have shown that high methionine intake can increase plaque formation in arteries, but this is unlikely to occur in horses under normal dietary regimens.

DL-Methionine Amino Acid for Horses


  • Hoof & coat quality
  • Maintain healthy joints
  • Exercise recovery
  • Antioxidant status

Tryptophan Amino Acid Supplements for Horses

Tryptophan is often marketed as an equine supplement that has a calming effect on nervous horses. However, the evidence to support this claim is not clear.


  • Required to make the neurotransmitter serotonin in the brain which is associated with appetite regulation, decreased anxiety, aggression and fearfulness.
  • Although tryptophan is often marketed as a calming agent for nervous horses, this has not been reliably demonstrated in horses.
  • In fact, research that looked at behavioural responses following tryptophan supplementation have shown no calming effect in horses.
  • Required to synthesize the hormone melatonin which is critical for sleep onset in horses and other animals.
  • Used to make vitamin B3 (niacin) in the liver which is important for blood flow, nutrient metabolism, skin health and many other biological functions.
  • Converted into kynurenine, a pro-inflammatory compound that is generated in response to oxidative stress.
  • Helps proteins such as hormone receptors “anchor” into the cell membrane so they can stay in the correct position for cells to respond to hormones appropriately.

Sources: Soybeans, oats, sunflower seeds, spirulina, animal proteins.

Deficiency: Tryptophan deficiency might be related to changes in mood including excitability.

Excess: In experimental studies, high doses of tryptophan were associated with lower stamina in endurance exercise training. Too much tryptophan is also associated with hemolytic anemia and respiratory distress in horses and ponies. [5] [6] These side effects are unlikely to occur with tryptophan levels commonly found in protein or amino acid supplements.

Leucine Amino Acid Supplements for Horses

Leucine is one of the three branched-chain amino acids (BCAAs), along with isoleucine and valine. In human nutrition, BCAAs are often used for muscle building. Similar to their role in human physiology, leucine and lysine are the most abundant amino acids in the horse’s muscle.

Based on recommendations from Dr. Eleanor Kellon, performance horses might benefit from 10 grams of L-leucine along with a sugar source after exercise to help with exercise recovery and rebuilding glycogen stores.

This is especially recommended for horses with poor topline and frequent muscle soreness.

Selenium, vitamin E, and magnesium are also critical for proper muscle function.


  • Leucine is high in skeletal muscle where it can be used to make new proteins or burned as an energy source.
  • Leucine activates the enzyme mTOR which stimulates protein synthesis, helping to build and repair muscle tissue.
  • Leucine itself is not gluconeogenic but it can be converted into the amino acid alanine which can be used to make glucose in the liver.
  • Involved in making hemoglobin – a protein found in red blood cells that binds oxygen to deliver it to various tissues of the body, including muscle.
  • Is part of enkepalins which are opioid-like compounds that can diminish the perception of pain.
  • Helps maintain blood glucose levels during exercise to support muscle endurance.
  • Stimulates insulin secretion when given after exercise which might help restore muscle glycogen levels that are depleted in exercise.
  • Is converted to HMG-coA (B-Hydroxy B-methylglutaryl-CoA) – a precursor for cholesterol which is important for maintaining healthy cell membranes. HMG-coA also forms ketone bodies that can be broken down for energy.

Sources: Leucine is widely available in horse feeds. Soybeans, hemp, oats, and corn are good sources of leucine.

Deficiency: Deficiency in the branched chain amino acids (leucine, isoleucine, valine) can limit exercise capacity and lead to early fatigue in exercise.

Excess: Excess leucine can interfere with niacin (vitamin B3) production in the liver.

Isoleucine Amino Acid Supplements for Horses

Isoleucine is a branched-chain amino acid, as are valine and leucine. These are often considered “muscle building” amino acids because they can stimulate protein synthesis in muscle which promotes muscle growth and tissue repair.


  • Isoleucine can be converted into propionyl-CoA that can be used to make glucose for energy.
  • Can be converted into acetyl-CoA which enters the Kreb’s cycle and generates ATP, the main energy source for cells. Acetyl-CoA can also form ketone bodies which can be used for energy, therefore isoleucine is considered “ketogenic”.

Sources: High in legumes including soybeans and alfalfa.

Deficiency: No specific symptoms related to isoleucine deficiency have been reported in horses.

Excess: No issues linked to too much isoleucine have been reported in horses.


Valine is a branched-chain amino acid, along with isoleucine and leucine.


  • Valine is needed for muscle coordination and proper muscle contraction.
  • It can be broken down for energy in all cells of the body. It is converted to succinyl-CoA which enters the Kreb’s cycle to generate adenosine triphosphate (ATP).
  • Valine is a “glucogenic” amino acid, meaning it can be used to make glucose which can be used immediately for energy or stored as glycogen to be burned for energy later.

Sources: High in legumes such as soybeans and alfalfa. It is also found in oats.

Deficiency: No specific issues due to valine deficiency have been reported in horses. In other animals, severe valine deficiency can cause neurological symptoms such as poor coordination.

Excess: No specific issues due to excess valine intake have been reported in horses.


Histidine is incorporated into various proteins in the body. It is also converted into other compounds that have important physiological roles, especially histamine which is important for the immune system, and carnosine – a possible neurotransmitter and acid-buffering molecule in muscle.


Histidine is converted to histamine which has several important functions in the body:

  • It is released from immune system cells called mast cells to fight infections.
  • Histamine release by immune cells causes blood vessels in the area to expand (vasodilation) which helps bring other immune cells to the area.
  • Histamine release during allergic reactions causes itchiness, sneezing and swelling. Antihistamine drugs can be used to treat these symptoms in horses.
  • It is a neurotransmitter in the brain where is involved in regulating sleep/wake cycles, memory and learning, anxiety, movement, feeding and drinking, and release of hormones.
  • Histamine stimulates gastric acid secretion by parietal cells in the stomach. Ranitidine is a histamine H2 receptor antagonist that has been used to treat gastric ulcers in horses by blocking the effects of histamine.
  • Histamine is involved in sexual arousal in males. In stallions, it affects contraction of blood vessels in erectile tissue.
  • Histamine negatively affects the protective layer that surrounds nerves called myelin. Antihistamines have been investigated as a treatment for multiple sclerosis. Whether this is relevant to horses is unknown.

Histidine is also used to make carnosine, a dipeptide of beta-alanine and histidine. Carnosine is found mostly in muscle and brain where it acts as an antioxidant that can protect cells from oxidative damage.

In the brain, it might act as a neurotransmitter and might protect against cognitive impairments associated with aging. In muscle, it acts as a buffer to neutralize acids created during exercise and improve exercise endurance.

Sources: Histidine is high in alfalfa and soybean proteins, canola meal, and cottonseed meal.

Deficiency: No specific issues due to histidine deficiency have been reported in horses.

Excess: No specific issues due to histidine excess have been reported in horses. Over-supplementation in rodents can reduce food intake causing weight loss and poor growth. It can also lead to high cholesterol levels.

Phenylalanine Amino Acid Supplements for Horses

Phenylalanine is the third-most abundant amino acid in equine diets. It is found at high levels in most forages and grains.


  • Phenylalanine is converted into the nonessential amino acid tyrosine which is used to make the neurotransmitter dopamine. Dopamine is important for signaling rewards and pleasure in the brain, control of movement, focus, and executive functions.
  • Changes in how dopamine works in reward and motivation centres of the brain are associated with stereotypic behaviours in horses including crib-biting, weaving and box-walking.
  • Phenylalanine is converted to epinephrine and norepinephrine, also known as adrenaline and noradrenaline. Epinephrine is a hormone released by adrenal glands in response to stress.
  • Norepinephrine is a neurotransmitter produced by the brain to activate the sympathetic nervous system. These are important factors in the fight-or-flight stress response that increases heart rate, breathing, and blood sugars. In horses, chronic disease, laminitis, and abdominal pain can also raise levels of these hormones and create a stress response.
  • Phenylalanine eases pain by preventing degradation of endorphins in the nervous system. Phenylalanine is sometimes included in joint health supplements for horses to help lessen the pain associated with arthritis and other joint problems.

Sources: Phenylalanine is abundant in the horse’s diet. It is high in soybean meal, alfalfa, pea, and potato proteins.

Deficiency: No specific issues due to phenylalanine deficiency have been reported in horses.

Excess: In excess amounts, this amino acid can interfere with serotonin production in the brain because it uses the same transporter as tryptophan to pass the blood-brain barrier (BBB).

If phenylalanine is very high in the blood it could prevent tryptophan from reaching the brain to make serotonin. This is unlikely to be an issue in typical equine diets.

Arginine Amino Acid Supplements for Horses

Some sources classify arginine as a conditionally essential amino acid for horses because of its role in supporting the immune system. Arginine deficiency might impair the immune system and cause illness to persist for longer than it otherwise would.

For this reason, arginine is considered conditionally essential during times of illness. However, other sources suggest arginine should always be considered an essential amino acid for horses.


  • Used to make nitric oxide which dilates blood vessels (vasodilation) to increase blood flow. L-arginine supplementation might benefit exercising horses by increasing blood flow to the lungs and muscles.
  • Supports reproductive health by improving blood flow to the uterus. L-arginine supplementation in pregnant and postpartum mares decreased uterine fluid levels which might improve conception rates for a subsequent pregnancy.
  • Supports immune cells, especially T cells that are important for protecting against viruses, bacteria, and cancer cells.
  • Is used to make creatine, along with metabolites of the amino acids glycine and methionine. Creatine is considered an energy boosting compound because it is involved in regenerating ATP, the main energy currency of the cell.

Sources: Arginine is high in soybean meal and linseed meal. Arginine alpha-ketoglutarate (AAKG) is sometimes used as a supplement to add arginine to the diet.

Deficiency: During periods of infection or disease, an arginine deficiency might impair the immune response and prolong the illness.

Excess: Excess arginine can affect lysine absorption and use by cells. This can exacerbate symptoms of protein deficiency by decreasing lysine availability in the body, which is usually already the most deficient amino acid in equine diets.

Conditionally Essential Amino Acids

The remaining 11 amino acids are considered non-essential because they can be made within the body and do not need to be provided by the diet. As such, deficiency is generally not as much of a concern with these amino acids because they can be made endogenously.

Some amino acids are considered “conditionally essential” because the endogenous production does not meet demands under certain circumstances.

During periods of high demand, including rapid growth, stress or heavy work load the following amino acids can become essential for horses:

  • Cysteine
  • Glutamine
  • Glycine
  • Proline
  • Serine
  • Tyrosine

Cysteine is synthesized from methionine and serine. When diets are low in methionine there may not be enough for adequate cysteine synthesis. This could impair keratin protein synthesis in hooves leading to weak, brittle hooves over time.

Glutamine and serine are conditionally essential under intensive training conditions because they are lost in sweat and broken down at faster rates than they are synthesized.

During the exertion and recovery period, they become temporarily conditional and must be supplied by absorption from the gut.

Glycine and proline are conditionally essential during periods of rapid growth. Collagen protein found abundantly in cartilage of joints is high in glycine, proline and lysine.

During growth, the high rate of collagen synthesis outpaces the endogenous supply of glycine and proline, therefore they must be supplied in the diet of weanlings.

Tyrosine is made from the essential amino acid phenylalanine. Tyrosine is used to make neurotransmitters and the stress hormones epinephrine (adrenaline) and norepinephrine (noradrenaline).

Prolonged stress that induces ongoing production of these hormones can deplete tyrosine levels, making it conditionally essential.

Non-Essential Amino Acids

The remaining amino acids are always considered non-essential in all mammals:

  • Alanine
  • Asparagine
  • Aspartic acid (Aspartate)
  • Glutamic acid (Glutamate)
  • Selenocysteine

For these amino acids, the endogenous supply and dietary levels are sufficient to meet the needs for protein synthesis even during periods of high demand.

Even though these are non-essential, they have some interesting characteristics in equine physiology that are worth noting.

Alanine Amino Acid Supplements for Horses

Alanine is part of the glucose-alanine cycle (Cahill cycle) that is important for supplying energy to the exercising muscle. In muscle, glucose is a major source of energy during exercise.

When it gets broken down for energy, lactate and alanine are produced. These travel to the liver and are re-formed into glucose which can travel back to the muscle to provide energy.

Beta-alanine is a naturally occurring amino acid that is different from alanine. It is not incorporated into proteins. Instead, it is used to make carnosine, a dipeptide of beta-alanine and histidine.

Carnosine is an antioxidant found at high levels in muscle. It can buffer the acid produced during exercise and support exercise endurance.

Asparagine Amino Acid Supplements for Horses

Asparagine can be made from other amino acids, namely glutamate, glutamine and aspartate.

In horses with laminitis, changes in the gut microbiome were associated with increased asparagine, but it remains to be seen what role, if any, asparagine plays in laminitis. [20]

Aspartic Acid (Aspartate)

The enzyme aspartate aminotransferase (AST) is found mostly in the liver and muscle. It is often measured in blood tests as an indicator of liver damage. When liver cells are damaged, they release AST into the bloodstream, leading to increased levels in the test.

In horses, high levels of AST can indicate acute liver damage due to infections related to gut issues, such as enteritis. It could also indicate chronic liver damage due to high iron intake.

High levels of AST could also reflect muscle damage due to “tying-up” or exertional rhabdomyolysis. It might also identify horses that experience rhabdomyolysis without showing clinical signs such as muscle stiffness and pain.

Glutamic Acid (Glutamate)

Glutamate is very similar in structure to the amino acid glutamine.

It is an important excitatory neurotransmitter, a chemical that nerves use to send signals to each other. It is found in over 90% of connections (synapses) between nerves.

The enzyme glutamate dehydrogenase (GLDH) is found in the liver. Similar to AST, it is measured in blood tests and high levels indicate possible liver damage.

Selenocysteine Amino Acid Supplements for Horses

Selenocysteine is a form of cysteine that contains selenium in place of sulfur. It is an important for making several so-called “selenoproteins”.

Selenoproteins include the antioxidant enzymes glutathione peroxidase and thioredoxin reductase.

The selenoprotein iodothyronine 5-deiodinase is important for making the thyroid hormone T3 which circulates in the blood. It converts the thyroid hormone T4 to T3 by removing an iodine atom from T4.


Conditionally-essential and non-essential amino acids are not as much of a concern for diet formulation as essential amino acids because they can be made within the body.

However, in certain conditions it is worth looking into their roles in the physiology of horses.

For instance, exercising horses could gain from beta-alanine supplements to increase the buffering power of carnosine.

Animals that are growing or who undergo intensive exercise and exposed to stressors, such as trailering or competition could be benefited by amino acid supplements.

Our Equine Nutritionists will evaluate your horse’s diet and offer suggestions on amino acid nutrition at these times.

Amino Acid Requirements

Of the essential 10 amino acids Of the essential amino acids, only the need for lysine was carefully determined by conducting scientific tests on horses.

Horses of mature age with the bodyweight of around 500 kilograms (1100 pounds) need a minimum of 18 grams daily of lysine in order to avoid the deficiency.

However, the suggested amount to ensure the optimal rate of protein synthesis is 27 grams daily of Lysine.

The most common suggestion is that lysine accounts for 4.3 percent of the crude protein consumed in our diet.

Since the skeletal muscle is the most significant protein storage facility within the body and is the largest protein reserve in the body, researchers analyzed the amino acid composition of the muscle in horses and utilized this to determine the optimal levels of essential amino acids, in comparison to the requirements for the amino acid lysine.

If the lysine requirement has been fulfilled, it can be concluded that all amino acids essential to life are present in sufficient quantities to aid in the synthesis of proteins within the body.

Table: Essential Amino Acid Requirements for Horses at Maintenance

Amino AcidProportion of LysineRequirement (g / day)

Common Protein Sources for Horses

The very best protein resources have the 10 necessary amino acids in proportions that are close to preferred proportions. Practical factors to consider like palatability, expense, uniformity of the product, and also schedule are likewise essential variables to think about when picking a protein source.

Alfalfa Proteins Amino Acid Supplements for Horses

Alfalfa is a nutrient-dense grass forage that is commonly given to horses. It is a great source of protein, fiber, and digestible energy . It also is low in Non-structural carbohydrate (NSC) which comprise glucose and other starches. Alfalfa hays are an excellent option for horses who have heavy workloads or are difficult keepers.

Protein content: Typically composed of 17 – 25% crude protein (on a dry matter basis).

Amino acid composition: Low levels of lysine, threonine and methionine.

Pros and cons: Alfalfa is a readily available, nutrient-dense forage that can support gastric health by keeping the stomach full for longer and providing calcium as a buffer to stomach acid.

However, excessive amounts of alfalfa consumed in the diet can offer excessive calories for horses that are sedentary and cause overweight and equine metabolic syndrome as well as the condition known as insulin resistance.

Certain horses are sensitive to the proteins found in alfalfa hay and may suffer the symptoms of an allergy. The signs of the intolerance to alfalfa may include itching and excitability, as well as irritable behavior, weight loss as well as changes in skin and hoof condition, diarrhea and other digestive issues.

Soybean meal Amino Acid Supplements for Horses

Soybean meal is frequently included in equine diets since it is easily available and offers significant amounts of amino acids. Soybeans that are raw should not be given to horses since they have antinutritive components. They are destroyed in the process of extraction of oil that leaves soy meal as a healthy by-product.

Protein content: Typically contains 44-48% crude protein, on an as-fed basis.

Amino acid composition: High in lysine (up to 30g/kg), threonine (up to 15g/kg) and arginine (up to 39g/kg). Low levels of methionine (up to 4g/kg).

Pros and cons: Soybean meal is a great option to meet the requirements for lysine in horses with the typical inclusion rate. A few reports suggest that horses are susceptible to allergies to soy protein, but there isn’t any evidence that supports this idea.

Canola meal Amino Acid Supplements for Horses

Canola meal is widely used for horses due to an similar appearance like soy meal and is relatively cheap. It is a by-product from canola oil production that is extracted using solvent or mechanical extraction.

Protein content: 36-41% crude protein (on a dry-matter basis).

Amino acid composition: Lysine (up to 25 g/kg), threonine (up to 18 g/kg), methionine (up to 5 g/kg). Also high in leucine (up to 30 g/kg) and arginine (up to 25 g/kg).

Pros and cons: An abundant protein source that offers the same nutritional profile as soybean meal, and is highly tasty. It is not to be confused with the rapeseed (an older version of canola) that has glucosinolate, which can affect thyroid function and shouldn’t be fed to horses.

Ground Flax Amino Acid Supplements for Horses

Flax that is freshly ground (also called Linseed) is a great energy source for horses. It is also a good source of alpha Linoleic acid (ALA) – an essential omega-3 acid which is essential to the diet of horses. It’s also a great source of protein, however it contains lower levels of the amino acid lysine than soybean meal and canola meal.

Protein content: Ground flax provides 26% crude protein, on a dry-matter basis.

Amino acid composition: Lysine (10g/kg), threonine (8g/kg), methionine (4g/kg). High in arginine (21g/kg).

Pros and cons:A cost-effective and readily available feed that offers a balanced mix of amino acids, fats, and minerals.To avoid rancidity products should be bought or freshly ground prior to feeding.

Corn gluten meal Amino Acid Supplements for Horses

The corn gluten meal can be a byproduct of corn syrup and corn starch production, which is often used in commercial feeds for horses. While it has a protein level that is very high but it is not able to offer high levels of lysine, and shouldn’t be considered to be a the primary source of protein for horses.

Protein content: Approximately 65% on a dry-matter basis.

Amino acid composition: Low in lysine (7 g/kg), moderate levels of threonine (17 g/kg) and methionine (13 g/kg).

Pros and cons: Although readily available, it can vary greatly in energy content and has undesirable ratios of phosphorus to calcium.

Dried Distiller’s Grains Amino Acid Supplements for Horses

Dried distiller’s grain is distilleries’ by-products that are created from a range of grains. They’re a protein that is a fuel source for horses. They contain significantly lower levels of sugar and starch than the grain that was originally used.

But, the composition of the product can differ from batch to batch and feeding this product could result in mineral and vitamin imbalances when not included in an appropriately designed diet.

Protein content: Typically around 25% crude protein (on a dry-matter basis).

Amino acid composition: Amino acid content varies depending on the type of grain, but cereal grains are generally low in lysine.

Pros and cons: Accessible, delicious and cheap in areas that are close to distilleries. Do not confuse with Dried Distiller’s Grain with Solubles (DDGS) which is the primary by-product of the production of ethanol, which is not recommended to feed to horses. DDGS may contain large amounts of mold, and also has high levels of phosphorus possibly causing imbalances in calcium.

Spirulina Amino Acid Supplements for Horses

Spirulina can be described as dried blue and green algae that’s utilized as an equine supplement to help improve respiratory and immune health in horses. It is not commonly utilized as a main protein source, but it could boost the protein content in the horse’s diet and provide significant levels of vitamins and minerals.

Protein content: Approximately 52% crude protein (on a dry matter basis).

Amino acid composition: Complete protein that provides all the essential amino acids but is low in lysine.

Pros and cons:

Spirulina is considered to be an horse “superfood” because it contains all the amino acids that are essential and minerals and vitamins that offer antioxidant and anti-inflammatory benefits.

Certain horses might be reluctant to eat this powder initially due to its distinct scent. Spirulina may be rich in iron and should be taken into consideration when feeding it to horses suffering from equine metabolism syndrome, or Cushing’s disease or PPID.

Bulk Spirulina Powder Equine Supplement


$33.99 per 1 kg

  • Supports immune function
  • Used in horses with allergies
  • Supports metabolic health
  • Rich in vitamins & protein

Potential Equine Protein Sources

Proteins are the most costly macronutrient found in the horse’s diet. The competitive demand for common protein sources like canola meal and soybean meal in all livestock industries increases their price as well as the total cost of feeding horses.

There are also concerns about sustainability of the environment in the case of many protein sources because of the increasing demand for them.

Proteins derived from insects are being developed as an environmentally sustainable and high-quality alternative to these conventional sources.

The idea of eating insects may not sound appealing initially However, when you consider that horses are likely to consume a variety of insects and larvae when they graze, this is not a shady protein source for them.

Of the numerous options of insect-derived proteins Black crickets and soldier fly larvae are the most suitable as a source of mass manufacturing and are available for human and pet consumption.

Black Soldier Fly (BSF) Larvae

Black soldier fly ( Hermetia illucens) is the common household fly found across North America and Europe. The larvae transform organic waste from food production into protein of high quality..

Protein Content: Protein content in the crude form is different based on the food the animal is being fed usually between 30 and 45 percent.

Amino acid composition: BSF larvae are high in lysine (22 g/kg) and methionine (9 g/kg).

Pros and cons: As the production of BSF larvae grows and expand, this source of protein will be more readily available and provide a reliable, protein source of high-quality.

There are no studies published on the palatability, inclusion or digestibility BSF on horses. For monogastric animals, it’s believed that BSF larvae that are ground BSF larvae may replace about 50 percent of the soybean meal.

Cricket Amino Acid Supplements for Horses

Crickets are a second option to source insect protein. The ground cricket is abundant in protein, and is considered to be a total protein as it has all the amino acids that are essential. It’s also a good source of trace minerals zinc, copper, and manganese.

Protein content: Cricket powders contain 42 – 46% crude protein.

Amino acid composition:

Cricket protein is comprised of 3.5 percent lysine and 33% threonine and methionine, which is 1. It’s also a great supply of leucine.

Pros and Cons: Like BSF larvae with the same characteristics, and as production grows, cricket powder will become more readily accessible. Horse studies aren’t as thorough research, however studies in chickens and goats suggests that it could be able to replace as much as 50 percent of the soybean meal without any negative impacts and may even improve the health of some reproductive indicators.

With all the possibilities for nutritious protein sources and their comparative cost when compared to other ingredients that are active It is always recommended to consult with an expert in horse nutrition to help you improve the diet of your horse.

This is about ensuring that the essential amino acid requirements are met to ensure protein synthesis that is healthy and improves overall health and to reduce excessive intake of healthy protein.

You could send your horse’s diet regimen and Mad Barn’s experts in horse nutrition will provide a comparable assessment and specific recommendations.

Equine Challenge™ Pro Amino contains all 10 major essential amino acids* plus 6 non essentials (Alanine, Arginine*, Cystine, Glycine, Histidine*, Isoleucine*, Leucine*, Lysine*, Methione*, Phenylalanine*, Proline, Serine, Threonine*, Tryptophen*, Tyrosine, Valine*). Equine Challenge™ Pro Amino comes in a milled flaxseed base with added chia seed. Both flaxseed and chia seed are excellent sources for amino acids.

Equine Challenge™ Pro Amino can be used to boost the amino acid content of your equine diets and contains no added vitamins or minerals.

Healthy proteins are made up of devices called amino acids. PROteins are synthesized from offered amino acids that are ingested or synthesized by the horse and are utilized to develop Muscular tissue, Bone, Blood Components, Hormones, Peptides, Antibodies.

Amino acids are needed for healthy protein synthesis, and also numerous can be made by tissues of the body. Nevertheless, ten of these amino acids, known as important amino acids, have to be provided to the horse with nutritional sources:

Arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, as well as valine. If you’re not sure your horse is getting sufficient, supplementing with Equine Challenge ™ Pro Amino will certainly alleviate your mind.

For circumstances in which healthy protein requirements will be greater, such as development, pregnancy, and also lactation, make sure to re-evaluate your horse’s supply to see to it all requirements are being met.

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