A

ADF (Acid Detergent Fibre)
In hay and pasture tests for horses, ADF is an important indicator of the fibre content in forage and plays a significant role in digestibility. It refers to the portion of the plant cell wall that remains after a sample has been treated with an acidic detergent, typically sulfuric acid. It primarily includes cellulose and lignin, which are the structural components of plants.

The higher the ADF, the less digestible the forage is likely to be because cellulose and lignin are harder for horses to break down compared to other plant components like starches or simple sugars.

Amino Acids
Amino acids are organic compounds that serve as the building blocks of proteins, playing a role in numerous biochemical processes within a horse. They are crucial for the synthesis and repair of muscle tissue, enzyme production, hormone regulation, and immune system function.

Antioxidants

Antioxidants are compounds that protect the body from oxidative stress caused by free radicals, preventing cell damage and inflammation. Horses experience oxidative stress from exercise, aging, and environmental factors. Antioxidants support immune health, reduce inflammation, and protect against conditions like muscle soreness and joint degeneration.

B

Big Head
Big Head, or the technical name, Nutritional Secondary Hyperparathyroidism (NSH), is a metabolic bone disorder in horses resulting from an imbalance between calcium and phosphorus in the diet. This condition typically develops when there is a deficiency of calcium or an excess of phosphorus in the diet which is often due to the consumption of high oxalate forages or a poorly balanced grain diet.

Certain tropical grasses contain high levels of oxalates, a naturally occurring compound which binds calcium, magnesium and potassium, preventing absorption and contributing to the development of a secondary calcium deficiency. Secondary deficiencies occurs when the horse is receiving enough of a certain nutrient, but the absorption or availability is impaired, which lead to signs of that deficiency.

The signs of Big Head arise as bones lose their mineral content, in an attempt of the horses body to maintain blood calcium levels. This leads to, bone weakness, and cartilage disruption. Early symptoms include shifting lameness, muscle tremors, joint tenderness, reluctance to move, incoordination and a stiff gait. As the condition progresses, the loss of bone integrity causes distortion of the affected bones, particularly in the facial region, resulting in the hallmark “big head” appearance.

Diets with less that 0.5% oxalates are considered safe and not likely to contribute to calcium deficiencies.

Bioavailability
Bioavailability is the proportion of a nutrient or substance that is absorbed and made available for use in the body after ingestion

Beet Pulp
Beet pulp is a byproduct of sugar beet processing and is commonly used as a high-fibre feed ingredient for horses. It is made from the fibrous residue left after the sugar has been extracted from sugar beets. Beet pulp is typically available in either dried flakes or pelleted forms usually fed soaked in water first.

Beet Pulp
Beet pulp is a byproduct of sugar beet processing and is commonly used as a high-fibre feed ingredient for horses. It is made from the fibrous residue left after the sugar has been extracted from sugar beets. Beet pulp is typically available in either dried flakes or pelleted forms usually fed soaked in water first.

C

Chromium
Chromium is an essential trace mineral that plays a key role in carbohydrate metabolism by enhancing the action of insulin, which helps regulate blood sugar levels. It is often included in horse diets, particularly for performance horses, to improve their metabolic efficiency and help with the processing of glucose.

C3 Plants
C3 plants are a type of plant that primarily uses the C3 pathway for photosynthesis, which is the most common photosynthetic pathway in plants. In horses, C3 plants are particularly relevant because they make up a large portion of the forage in their diets, especially cool-season grasses and legumes. C3 plants prefer temperate climates with moderate sunlight, are more tolerant of frost, grow in both wet and dry conditions and have an optimum temperature range of 15-30 degrees Celsius. C3 plants store their excess energy as fructans, which can accumulate to high levels.

C4 Plants
C4 plants are a group of plants that use the C4 photosynthetic pathway, which is an adaptation to hot, dry environments. This pathway allows plants to fix carbon dioxide (CO2) more efficiently under conditions of high temperature and low water availability, making C4 plants better suited for tropical and subtropical climates. C4 species like temperatures of 25-40 degrees Celsius and love warm, strong sunlight. C4 plants store their excess energy as starch and generally have a higher fibre content than C3 plants, but lower protein quality. Some C4 grasses and hays contain oxalates which can reduce the absorption of calcium in the horses diet.

Calcium
Calcium is an essential mineral that plays a role in bone and tooth formation, muscle function, nerve transmission, blood clotting, and hormonal regulation. Approximately 99% of calcium is stored in the bones and teeth, where it contributes to strength and structure. It is essential for bone growth and maintenance, working in balance with phosphorus. Calcium also facilitates muscle contraction and relaxation by influencing muscle fibres, and it is crucial for the transmission of nerve impulses. Additionally, calcium is involved in blood clotting, aiding in wound healing and preventing excessive bleeding.

Calories
Calories is a term often used to describe energy in horse feed, though technically we measure energy in megajoules per kilogram (MJ/kg) of Digestible Energy (DE).

Chelated
Chelated refers to the process by which minerals are bound to organic molecules, typically amino acids or peptides, to form a stable complex. This binding enhances the mineral’s bioavailability, meaning it is more easily absorbed and utilised by the horse’s body compared to non-chelated minerals.

Chlorine
Chlorine is a mineral for horses, primarily found in the form of chloride, which is the negatively charged ion (anion) that combines with sodium to form salt (sodium chloride or NaCl). It plays a crucial role in maintaining fluid balance, electrolyte balance, and acid-base equilibrium within the horse’s body. Chlorine is vital for the production of gastric hydrochloric acid (HCl) in the stomach, which aids in digestion and helps break down food. It also supports the proper functioning of nerve cells and muscle contractions by helping to regulate osmotic pressure and fluid distribution inside and outside of cells.

Cobalt
Cobalt is a trace mineral for horses, playing a role in vitamin B12 synthesis. Vitamin B12, also known as cobalamin, is necessary for the production of red blood cells, as well as for proper nerve function, DNA synthesis, and metabolism of fatty acids and amino acids. Cobalt itself is a central component of vitamin B12 and is absorbed from the horse’s diet primarily through the hindgut, where gut microbes synthesise the vitamin.

Colic
Colic in horses refers to abdominal pain caused by a variety of conditions affecting the digestive system. It is one of the most common and serious health issues in horses, ranging from mild discomfort to life-threatening situations. Colic can result from many causes, including gas accumulation, intestinal impaction, twisted intestines, enteritis, or blockages. The severity and type of colic can vary, and its symptoms may include rolling, pawing at the ground, sweating, looking at the abdomen, and lack of appetite.
The digestive system of horses is particularly vulnerable to colic due to their non-ruminant digestive system, which is designed to process a high-fibre, forage-based diet. Colic can occur when horses are fed improperly, such as when they are given too much grain, too little roughage, or sudden changes in diet. Poor dental health, dehydration, lack of exercise, or stress can also contribute to colic.

Complete Feed
A feed formulated to provide all essential nutrients, including vitamins, minerals, and sufficient fibre, to support overall health and promote digestive well-being.

Condition Score
A system used to assess and quantify the body fat of a horse based on its physical appearance. It provides an objective method for evaluating a horse’s nutritional status.

Copper
Copper is a trace mineral in horses that plays a role in numerous functions. It is involved in the formation of haemoglobin (the protein in red blood cells that carries oxygen), the production of collagen and elastin (important for connective tissues, bones, and joints), and the proper function of the nervous system. Copper also acts as a cofactor for several enzymes involved in the metabolism of iron, energy production, and the maintenance of immune function.

Crude Fibre (CF)
Crude Fibre (CF) with horses refers to the portion of plant material in their diet that is primarily composed of cellulose, hemicellulose, and lignin. It is a measure of the indigestible carbohydrates in forage, which are found in the cell wall of plants. While these fibrous components cannot be fully digested by the horse’s stomach, they play an essential role in the digestive process, particularly in the hindgut, where fermentation occurs.

Cushing’s Disease
Cushing’s disease, also known as Pituitary Pars Intermedia Dysfunction (PPID), is a hormonal disorder in horses caused by a tumour or enlargement in the pituitary gland, located at the base of the brain. This abnormal growth leads to the overproduction of pro-opiomelanocortin (POMC), a precursor protein that, when secreted in excess, results in an increased release of hormones such as adrenocorticotropic hormone (ACTH). This disruption in hormonal balance causes the characteristic symptoms of Cushing’s disease.

Common signs of Cushing’s disease include a long, curly coat that fails to shed properly, excessive sweating, lethargy, muscle wasting, and abnormal fat distribution (often seen in the crest of the neck, above the eyes, and around the tail head). Affected horses may also experience delayed wound healing, increased thirst, and frequent urination. These symptoms are more commonly observed in older horses, typically those over 15 years of age, and can worsen over time if left untreated.

Diagnosis of Cushing’s disease is typically made through ACTH testing, which measures the level of ACTH in the blood, or the dexamethasone suppression test, which evaluates how the pituitary gland responds to a corticosteroid. Since early symptoms can be subtle, it’s important to consult a veterinarian if you suspect your horse may have Cushing’s disease. A vet can provide a proper diagnosis, guide treatment options, and help develop a management plan to improve the horse’s quality of life and prevent complications like laminitis and insulin resistance.

D

Developmental Orthopaedic Disease (DOD)
Developmental Orthopaedic Disease (DOD) in horses refers to a group of conditions that affect the growth and development of a horse’s bones and joints, typically seen in young, fast-growing horses. These disorders are caused by abnormalities in the normal development of the skeletal system, which can result in bone or joint deformities, lameness, and other musculoskeletal problems. DOD is most commonly observed in foals and young horses, particularly those that are growing rapidly, overfed, or genetically predisposed.

Digestible Energy
The portion of the energy in a horse’s diet that is absorbed and utilised by the body after the feed has been digested. It represents the energy available for maintenance, growth, work, and other bodily functions. DE is calculated by subtracting the energy lost in the faeces (undigested material) from the total energy in the feed, which provides an estimate of the energy that the horse can actually use.

E

Ethanol Soluble Carbohydrate (ESC)
Ethanol Soluble Carbohydrate (ESC) refers to a specific fraction of carbohydrates in a horse’s feed that is soluble in ethanol. These carbohydrates, primarily consisting of simple sugars such as glucose and fructose, are readily digestible by the horse’s digestive system and can rapidly elevate blood sugar levels. ESC is an important measure in assessing the sugar content of forage or feed ingredients, as it indicates how much of the carbohydrate content is available for quick energy release.

Equine Metabolic Syndrome (EMS)
Equine Metabolic Syndrome (EMS) is a complex metabolic disorder in horses, characterised by insulin resistance, adiposity (particularly in the neck and crest area), and an elevated risk of laminitis. It commonly affects horses that are overweight or have an excessive accumulation of body fat, although it can also occur in horses of normal weight. The hallmark of EMS is insulin resistance, where the horse’s cells become less responsive to insulin, a hormone responsible for regulating blood glucose levels. In response, the body compensates by producing higher levels of insulin, which can lead to hyperinsulinemia, a condition that disrupts normal metabolic processes and increases the susceptibility to laminitis, an inflammatory condition of the hoof.
It is recommended that the total amount of WSC and starch in the diet be kept below 10%, for horses suffering from EMS.

F

Fatty Acids
Fatty acids are lipid components that play a role in energy metabolism and cellular function. These long-chain hydrocarbons are key for the formation of cell membranes, the synthesis of hormones, and the regulation of various physiological processes, including inflammation and immune function. Horses are unable to produce certain fatty acids, called Essential Fatty Acids (EFAs), so these must be supplied in the diet. Fatty acids are categorised into saturated, monounsaturated, and polyunsaturated types, each with distinct functions. Within these fatty acids are the three main omega fatty acids, including omega-3, omega-6 which are polyunsaturated and omega-9 which are monounsaturated.

Folic Acid
Folic acid in horses is a water-soluble B-vitamin (also known as vitamin B9) that plays a role in various metabolic processes, particularly in the formation of red blood cells and the synthesis of DNA. Folic acid is essential for cell division and growth, making it especially important for pregnant mares, young horses, and horses undergoing periods of growth or recovery from illness.

Flax
Flax (or flaxseed) in horses refers to the seeds of the flax plant (Linum usitatissimum), which are commonly used as a dietary supplement due to their rich nutritional profile. Flax is an excellent source of omega-3 fatty acids, particularly alpha-linolenic acid (ALA), which is beneficial for reducing inflammation, promoting healthy skin and coat, supporting joint health, and improving overall cardiovascular health in horses. It also contains fibre, protein, vitamins, and minerals that contribute to digestive health.

Fructan
Fructan is a type of carbohydrate found in certain grasses and plants, particularly in cool-season grasses. It is a polymer of fructose molecules and serves as a storage carbohydrate in C3 plants, similar to starch’s role in C4 plants. Unlike starch, which is easily digested by horses, fructan can be more difficult for horses to digest, as they lack the enzymes necessary to break it down effectively in the small intestine.

Fructans are primarily fermented in the cecum and colon by the horse’s gut bacteria, which can lead to the production of gases and lactic acid. This fermentation process can cause digestive upset or discomfort, particularly when horses consume large amounts of fructan-rich forage.

G

Gastric Ulcers
Gastric ulcers in horses, also known as Equine Gastric Ulcer Syndrome (EGUS), are sores or lesions that develop in the lining of the horse’s stomach, most commonly in the squamous mucosa (the upper part of the stomach) and glandular mucosa (lower part of the stomach). These ulcers occur when the stomach’s protective mechanisms are overwhelmed by the constant production of gastric acid, leading to damage of the stomach lining.
The condition is often linked to factors such as intense exercise, fasting, stress, and high-concentrate, low-fibre diets, all of which contribute to increased stomach acid production. Additionally, continuous feeding practices (such as grazing or constant access to hay) help buffer stomach acid, whereas intermittent feeding or limited access to forage can worsen the condition.
Signs of gastric ulcers in horses can vary, but common symptoms include poor appetite, weight loss, poor performance, irritability, behavioural changes, excessive salivation, colic, and bloating. In some cases, horses may be reluctant to eat or exhibit signs of discomfort, especially after exercise.
Diagnosis of gastric ulcers is typically confirmed through gastroscopy, where a camera is inserted into the stomach to visually inspect for the presence of ulcers. Treatment options include the use of proton pump inhibitors or H2 blockers to reduce stomach acid production, along with dietary changes to ensure more consistent forage availability, low starch diets and the inclusion of buffers or supplements to support gastric health.

Good Doer
A horse that is able to maintain or gain weight easily, often with minimal feed intake.

H

Hay Belly
Hay belly in horses refers to a condition where the horse appears to have a swollen or distended abdomen, typically caused by an accumulation of undigested hay or fibre in the digestive system. It is most commonly seen in horses that are fed large amounts of low-quality hay, which is high in fibre but difficult to digest.
Symptoms of hay belly include a large, soft, or sagging belly, particularly in horses with poor muscle tone in the abdominal area. While it can give the appearance of excess weight, it does not necessarily mean the horse is obese or unhealthy.

Hind Gut
The large intestine of a horse.

HYPP (Hyperkalemic Periodic Paralysis)
HYPP (Hyperkalemic Periodic Paralysis) is a genetic disorder in horses that affects the regulation of potassium levels in the blood and muscles. It is caused by a mutation in the SCN4A gene, which affects the function of sodium channels in muscle cells. The disorder is most commonly seen in Quarter Horses, Paint Horses and Appaloosas particularly those with the impressive bloodline.
When a horse with HYPP is stressed, exercised, or fed a high-potassium diet, the mutated gene causes an abnormal flow of sodium and potassium in the muscles, leading to muscle weakness, tremors, or even paralysis. These episodes, known as attacks, can range from mild muscle stiffness to severe paralysis, and in some cases, they can be life-threatening.
The most focal management strategy for horses with HYPP is to restrict their dietary potassium intake to less than 1% of their total diet. Grass and hay are the primary sources of potassium in a horse’s diet, with forages often containing more than 3% potassium. Factors like moisture content, maturity stage, and type of forage (legumes generally have higher potassium levels than grasses) can all influence potassium concentrations. While grains also contain potassium, the levels are typically lower, usually under 0.5%. To manage HYPP, it is recommended to feed tested hays or pastures where possible, particularly those cut at a later growth stage, such as grass hays, Oaten hay rather than legume hays like lucerne, which are higher in potassium.

I

Iodine
Iodine is a trace mineral in horses that plays a key role in the proper function of the thyroid gland. The thyroid gland uses iodine to produce thyroid hormones, which are critical for regulating metabolism, growth, and energy production. These hormones, thyroxine (T4) and triiodothyronine (T3), help control the body’s metabolic rate, influence digestion, support muscle function, and regulate the horse’s overall growth and development.

A deficiency in iodine can lead to hypothyroidism, which may cause symptoms such as lethargy, poor growth, weight gain, rough coat, and, in extreme cases, goiter (enlargement of the thyroid gland). On the other hand, excessive iodine can also be harmful, potentially leading to thyroid dysfunction and other metabolic issues.

Insulin Resistance
Insulin resistance (IR) in horses is a metabolic disorder where the body’s cells become less responsive to insulin, a hormone that regulates blood glucose levels. As a result, the pancreas produces excess insulin to compensate, leading to high levels of insulin in the blood, known as hyperinsulinemia. This condition is commonly associated with obesity, particularly around the neck and belly, and is often seen in older horses, ponies, or those with Cushing’s disease (PPID). Insulin resistance increases the risk of developing laminitis, a painful hoof condition. Symptoms include obesity, fatty deposits around the tailhead or eyes, lethargy, poor performance, laminitis, and increased thirst or urination. The causes of insulin resistance include high-starch or high-sugar diets, obesity, genetic predisposition, and conditions like PPID. Management focuses on dietary changes, including feeding a low-sugar, low-starch diet, regular exercise to improve insulin sensitivity, and weight control. In some cases, medication may be prescribed under veterinary supervision. Regular monitoring through veterinary checkups, including blood tests for insulin and glucose levels, is crucial to managing the condition and preventing complications like laminitis.

Iron
Iron is a trace mineral in horses that plays a role in the production of haemoglobin, the protein in red blood cells responsible for carrying oxygen throughout the body. Iron is also involved in various enzymatic processes and is necessary for the metabolism of cells and tissues. It helps maintain healthy blood and supports overall growth, development, and energy production.

K

Keratin
Keratin in horses is a fibrous structural that is primarily found in the skin, hair, hooves, and connective tissues.

L

Laminitis
Laminitis is a painful and potentially debilitating condition that affects the laminae, the sensitive tissues within the hoof that connect the hoof wall to the underlying bone (the coffin bone). In laminitis, these tissues become inflamed, weakened, and damaged, which can cause the coffin bone to shift or rotate within the hoof. This condition can lead to lameness, discomfort, and in severe cases, permanent damage to the hooves.
The causes of laminitis are varied, but common triggers include overconsumption of lush pasture (especially high-sugar grasses), obesity, trauma or injury to the hooves, infection (such as from severe colic or endotoxemia), and metabolic disorders like insulin resistance or Cushing’s disease (PPID). Other contributing factors can include excessive grain intake, high levels of non-structural carbohydrates (sugars and starches), and poor circulation to the hooves.
Symptoms of laminitis include lameness (often in the front hooves), heat in the hooves, increased digital pulses, and a rocking horse stance where the horse shifts weight off the painful feet. As the condition progresses, the coffin bone may rotate, and the horse may develop chronic, long-term hoof issues.
Prevention and management of laminitis focus on addressing the underlying causes, such as limiting access to lush pasture during high-sugar times, controlling body weight, and managing metabolic conditions like insulin resistance or Cushing’s disease. In severe cases, prompt veterinary intervention is necessary to provide pain relief, manage inflammation, and prevent further damage to the hooves. Regular hoof care, such as trimming and the use of appropriate footwear, may also help manage the condition and improve comfort for affected horses.

Lignin
Lignin is a complex, fibrous compound found in the cell walls of plants, particularly in the xylem of trees and other plants. It provides structural support and rigidity, helping plants maintain their shape and resist environmental stresses. In horses, lignin is an important component of plant fibre, especially in forages such as hay and grasses.
Lignin is considered an indigestible fibre for horses because their digestive system cannot break it down effectively. Unlike cellulose or hemicellulose, which can be partially digested by the horse’s hindgut (via fermentation in the cecum and colon), lignin passes through the digestive tract largely unchanged. As a result, it contributes to the overall fibre content of a horse’s diet but does not provide significant nutritional value in terms of energy or digestible nutrients.

Lysine
Lysine is an essential amino acid in horses, meaning it must be obtained through their diet because the body cannot produce it. Lysine plays a role in protein synthesis, growth, and muscle development. It is particularly important for the formation of collagen and elastin, which are key proteins in connective tissues, cartilage, and muscles.

M

Mannan-Oligosaccharides (MOS)
MOS (Mannan-Oligosaccharides) in horses refers to a type of prebiotic compound derived from the cell walls of yeast. MOS is used in equine nutrition as a feed additive to support gut health and improve digestive function. It works by binding to harmful pathogens in the digestive tract, preventing them from attaching to the gut wall, and promoting the growth of beneficial gut bacteria.

Methionine
Methionine is an essential amino acid in horses, meaning that it must be obtained from the diet since the body cannot produce it. It plays a role in protein synthesis, growth, and various metabolic processes. Methionine is particularly important for the health of a horse’s coat, hooves, and tissue maintenance.

Mycotoxin Binder
A feed additive designed to bind and neutralise mycotoxins—poisonous substances produced by moulds (fungi) that can contaminate feed, particularly grains and forages. Mycotoxins are harmful to horses and can cause a range of health issues, including gastrointestinal disturbances, immune suppression, poor performance, reproductive problems, and even toxicity in severe cases. Mycotoxin binders are typically made from natural substances like clays, yeasts, or activated charcoal, which have the ability to absorb the toxins in the gastrointestinal tract. Once bound, the mycotoxins are prevented from being absorbed into the bloodstream, reducing their toxic effects on the horse’s body.

N

NDF (Neutral Detergent Fibre)

NDF is a measure of the total fibre content in hay or forage, including cellulose, hemicellulose, and lignin. NDF indicates the bulkiness of the forage and affects how much a horse can consume. Lower NDF values typically indicate more digestible and palatable forage, while higher values suggest coarser forage that may limit intake.

NSC (Non-Structural Carbohydrates)

NSC refers to the sugars and starches in a horse’s diet. It is calculated by adding the starch and WSC results together. These carbohydrates are quickly digested and provide energy but can impact blood sugar levels. Managing NSC intake is critical for horses prone to metabolic issues like insulin resistance, laminitis, or equine metabolic syndrome. High NSC diets can trigger or worsen these conditions.

O

Omega Fatty Acids

Essential Fatty Acids (EFAs) play a crucial role in a horse’s overall health. The three main types of omega fatty acids for horses are omega-3, omega-6, and omega-9:

Omega-3 fatty acids include alpha-linolenic acid (ALA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA). They are important for brain health, vision, immune system function, exercise recovery, reduction of insulin sensitivity, joint health and the nervous system. Omega-3s can support anti-inflammatory mechanisms, particularly EPA and DHA (which commonly come from marine sources). Horses can convert ALA (obtained through fresh grasses, forages and other plant sources) into DHA and EPA, however this process is inefficient and doesn’t generate enough to benefit from their anti-inflammatory properties.

Omega-6 fatty acids include linolenic acid (LA) and arachidonic acid (ACA) which support the horse’s coat condition, joints, wound healing, bone growth and reproduction. Omega-6 fatty acids also play a very important part in inflammatory response, a natural process of healing. If horses receive too much omega-6, or it is not in balance with the omega-3 in the diet, it can be profinflammatory.

Omega-9 fatty acids include oleic acid (which is abundant in olive oil) and erucic acid (which is abundant in canola oil). The horse is able to manufacture omega-9 fats in their body from other unsaturated fats, so is considered nonessential to supply (unless the horse isn’t receiving enough omega-3 or 6 FAs) . Omega-9 fatty acids can help maintain a healthy hormone balance in horses.

P

Poor Doer
A horse that struggles to maintain or gain weight, despite being fed adequate amounts of food and receiving proper nutrition. These horses may have difficulty retaining condition, often appearing underweight, with a poor coat quality, and sometimes showing signs of lethargy.

Postbiotics

A postbiotic is a non-living byproduct of the fermentation process that occurs when prebiotic and probiotics are combined in a horse’s hindgut. Postbiotics improve the GI tract environment, allowing beneficial microorganisms to multiply and reduce the ability of harmful microorganisms to do the same. This can help with digestion, reduce inflammation, and improve the strength of the gut lining.

Prebiotics
Prebiotics are non-digestible food components, usually fibres or carbohydrates, that promote the growth and activity of beneficial bacteria (probiotics) in the gut. Unlike probiotics, which are live microorganisms, prebiotics serve as a food source for the beneficial microbes living in the horse’s digestive system, especially in the hindgut (cecum and colon). By stimulating the growth and activity of these beneficial bacteria, prebiotics help maintain a healthy balance of gut microflora, which is essential for optimal digestion.

Probiotics
Probiotics are live microorganisms, typically bacteria or yeasts, that provide health benefits when consumed in adequate amounts. They are commonly referred to as “good bacteria” because they help maintain or restore a healthy balance of gut microflora, particularly in the hindgut (the cecum and colon), which is essential for proper digestion.

Q

Quidding
Quidding in horses refers to the act of dropping partially chewed ‘balls’ of food from the mouth while eating, a behaviour that typically signals difficulty with mastication. When a horse is unable to properly chew its feed, it often leaves behind clumps of food, known as “quids,” either in its mouth or on the ground. This behaviour is often indicative of underlying issues affecting the horse’s ability to chew efficiently.

S

Selenium
Selenium is an essential trace mineral that plays a crucial role in various physiological processes, particularly as an antioxidant. It is involved in the protection of cells from oxidative damage, supports the immune system, and is important for the proper function of muscles and the cardiovascular system.

Slow Release Energy
Refers to a form of energy that is gradually made available to the horse over a longer period of time, as opposed to fast-release energy, which is quickly absorbed and utilised. This slow and sustained release of energy is typically derived from sources that are more fibrous and complex in structure, such as forages (hay, grass) and fibre-rich feeds.

Starch

Starch is a carbohydrate that provides an energy source for horses, generating fuel for exercise, growth, and metabolism. It is found in plant cell walls and in cereals like barley, corn, and oats. 

When a horse eats starch, the small intestine breaks it down into glucose molecules, which are then absorbed into the bloodstream. The pancreas releases insulin in response to the increase in blood glucose levels, which helps move glucose into cells for energy. Excess glucose is stored as glycogen in the horse’s liver and muscle cells. 

Starch can be problematic for horses if fed incorrectly or if they have unlimited access to high-starch feed. Some issues that can arise include high blood glucose levels, undigested starch passing into the large intestine, where it can ferment and cause undesirable consequences, and endotoxin shock if a horse consumes large amounts of cereals in one go, micro-organisms that die off can release endotoxins that enter the bloodstream and lead to toxic laminitis. 

Some horses, like those with pituitary pars intermedia dysfunction (PPID), may need a lower-starch diet. However, eliminating starch entirely for horses that do more than moderate work may also be risky and could reduce their performance.

Super Fibres
Super fibres are high in fibre and digestibility and are used to support digestive health, improve nutrient absorption, and provide slow-releasing energy. These fibres are typically more fermentable in the horse’s hindgut (cecum and colon) compared to traditional forages like hay or grass, making them ideal for horses that require additional support for their digestion or energy levels.

T

Topline
Topline in horses refers to the muscles along the back, with particular emphasis on the muscles over the withers, back, loin, and croup.

Tying Up
Tying up, also known as exertional rhabdomyolysis (ER), is a condition in horses that causes muscle cramping, stiffness, and pain, often following intense or unaccustomed exercise. It can occur in horses that are not properly conditioned, or those with underlying metabolic or genetic conditions, such as polysaccharide storage myopathy (PSSM). The symptoms of tying up include muscle rigidity, excessive sweating, reluctance to move, and discomfort, with the muscles often feeling firm to the touch. The condition can be triggered by factors like electrolyte imbalances, excessive carbohydrate intake, stress, or sudden, intense exercise.

V

Vitamin A
Vitamin A is a fat-soluble vitamin for horses that plays a role in maintaining healthy vision, skin, immune function, and cell growth. It is primarily obtained through the diet in the form of beta-carotene, a precursor found in green, leafy forage and certain vegetables. Once consumed, beta-carotene is converted to active Vitamin A in the liver. Vitamin A is particularly important for supporting the health of the eyes, helping to prevent issues such as night blindness, and maintaining healthy mucous membranes and skin. It also plays a key role in the immune system, helping the horse fight infections.

Vitamin B1
Vitamin B1, also known as thiamine, is a water-soluble vitamin for horses that plays a role in their metabolism. Thiamine is primarily involved in the conversion of carbohydrates into energy, making it essential for muscle function, nerve health, and overall energy production. It helps the body break down glucose into energy and is important for the proper functioning of the nervous system, supporting the transmission of nerve impulses.

Vitamin B2
Vitamin B2, also known as riboflavin, is a water-soluble vitamin that plays a role in energy metabolism for horses. Riboflavin is crucial for the proper functioning of multiple enzyme systems involved in the conversion of carbohydrates, fats, and proteins into energy. It also supports healthy skin, the eyes, and the nervous system.

Vitamin B3

Vitamin B3, or niacin, is a water-soluble vitamin that supports energy metabolism, healthy skin, and proper nervous system function. While horses typically synthesise enough niacin in their gut, supplementation may be beneficial for those with high energy demands or certain health conditions.

Vitamin B5

Vitamin B5, or Pantothenic Acid is a vital nutrient for horses that aids in energy production, fat metabolism, and the synthesis of essential compounds like coenzyme A. Horses generally produce sufficient amounts in their gut, but additional supplementation may support performance and recovery in high-stress situations.

Vitamin B6
Vitamin B6, also known as pyridoxine, is a water-soluble vitamin that plays a role in various metabolic processes in horses. It is primarily involved in amino acid metabolism, protein synthesis, and the production of neurotransmitters, which are vital for proper nerve function. Vitamin B6 also supports the horse’s immune system and helps maintain healthy skin and coat condition.

Vitamin B12
Vitamin B12, also known as cobalamin, is a water-soluble vitamin that plays a role in the metabolism of every cell in the horse’s body. It is involved in red blood cell formation, the synthesis of DNA, and the metabolism of fatty acids and amino acids. Vitamin B12 is particularly important for nerve function and the health of the nervous system.

Vitamin C
Vitamin C, also known as ascorbic acid, is a water-soluble vitamin that plays a role in antioxidant protection, immune function, and collagen formation in horses. Unlike humans, horses can synthesise Vitamin C in their liver from glucose, so they do not typically require it from their diet under normal circumstances. However, during times of stress, illness, or injury, a horse’s demand for Vitamin C can increase, and supplementation may be beneficial in such cases.
It is involved in the maintenance of healthy connective tissues, including ligaments, tendons, and cartilage, and is crucial for wound healing and the overall integrity of the skin. It also helps support the immune system by protecting cells from oxidative stress and promoting the function of white blood cells. Additionally, Vitamin C enhances the absorption of iron from the gastrointestinal tract, which is important for preventing anaemia.

Vitamin D
Vitamin D is a fat-soluble vitamin that plays a role in calcium and phosphorus metabolism in horses. It helps regulate the absorption of these minerals from the gastrointestinal tract and ensures proper bone health by promoting calcium deposition in bones and teeth. Vitamin D also helps maintain appropriate levels of calcium in the bloodstream, which is essential for muscle function, nerve transmission, and overall cellular processes.

Vitamin E
Vitamin E is a fat-soluble vitamin that plays a critical role in maintaining the health of horses. It functions primarily as a potent antioxidant, protecting cells from oxidative damage caused by free radicals. This is particularly important for the health of muscles, nerves, and the immune system. Vitamin E helps maintain the integrity of cell membranes, supports muscle function, and promotes normal immune responses. Deficiency in Vitamin E can lead to a condition known as equine neuroaxonal dystrophy (ENAD) or equine motor neuron disease (EMND), both of which affect the nervous system.

Vitamin K
Vitamin K is a fat-soluble vitamin essential for blood clotting in horses. It plays a vital role in the synthesis of clotting factors in the liver, which are necessary for the proper coagulation of blood and the prevention of excessive bleeding. Vitamin K is also involved in bone health by regulating calcium balance in the body, helping maintain strong and healthy bones.

Volatile Fatty Acids (VFA’s)
Volatile Fatty Acids (VFAs) in horses are short-chain fatty acids produced as by-products of the fermentation process in the horse’s hindgut. These fatty acids are primarily produced when fibre in the diet, such as grasses and hays, are broken down by microbial activity in the cecum and colon. The most common VFAs in horses are acetic acid, propionic acid, and butyric acid.

W

Water Soluble Carbohydrate (WSC)
Water Soluble Carbohydrates (WSC) refer to a group of carbohydrates that are easily dissolvable in water and can be rapidly absorbed into the bloodstream. They include simple sugars such as glucose, fructose, and sucrose, which are quickly available for energy. The current method for determining non-structural carbohydrates (NSC) is to add the Water Soluble Carbohydrates (WSC) and starch content. It is recommended that the total amount of WSC and starch in the diet be kept below 10%, for horses suffering from EMS, Cushing’s or Laminitis. 

Z

Zinc
Zinc is a trace mineral in horses that plays a role in immune function, wound healing, protein synthesis, and enzyme activity. It is involved in the formation of collagen, which is necessary for healthy connective tissues, and supports the proper function of the skin, hooves, and hair. Zinc also helps in the metabolism of carbohydrates, proteins, and fats, and is essential for proper growth and development in young horses.