Amino acids
The “building blocks” that form proteins. There are 20 different amino acids in total; the order in which they occur in a protein provides its specific characteristics.

Substances that protect the body’s cells from the harmful effects of free radicals and other oxidising compounds.

Average Daily Gain (ADG)
This describes the amount of weight increase seen in growing foals and can be used to monitor growth patterns. Usually expressed in kg per day with rates of 0.5 – 1.0kg being typical for a thoroughbred foal under 6 months of age.


Crib biting
This is classed as “abnormal behaviour” or a stereotypy, where the horse performs an action repetitively, in this case the horse bites, for example, the fence or stable door. Stereotypies are often associated with boredom or stress. Other stereotypies include windsucking, box walking and weaving.

Cushing’s syndrome
a condition caused by an overactive pituitary gland, symptoms include: long curly coat, patchy sweating, excessive thirst, excessive urination, laminitis and increased appetite without weight gain.

Cushingoid horse/pony
A horse or pony that is suffering from Cushing’s synd

Too little body water, Can results in a decline in athletic performance and can be life-threatening.

Normally refers to minerals and mineral salts (sodium, potassium, magnesium and chloride) present in the body’s fluids. Responsible for conducting electrical impulses for muscle contraction, internal water balance and skeletal tissue integrity.

Equine rhabdomyolysis syndrome (ERS)
Also known as tying up / azotoria / Monday morning disease - a muscular disorder that can cause varying degrees of muscle stiffness; factors thought to contribute to its occurrence include stress, high starch diets, exercising beyond fitness level and overfeeding of cereal on rest days.

Free Fatty Acids
Fat energy source created by the breakdown or mobilisation of stored body fat.

storage carbohydrates found in grasses; rapid fermentation of fructans in the hindgut may contribute to laminitis.

Gastric ulcers
Lesions formed in the lining of the stomach or duodenum.

Gastric acid
A gastric secretion which acidifies the stomach contents.

Gastric emptying
Term used to describe the mechanism and speed of the release of food from the stomach into the first part of the small intestine.

Humoral immune response
The immune response that recognises antigens on the surface of invading germs and then produces antibodies to inactivate them.

Describes a feed that may cause an increase in excitability, usually due to a relatively high cereal content. Opposite to this is a non-heating feed which is less likely to cause an increase in excitable behaviour when fed at the recommended rate.

Hindgut (Large intestine)
The portion of the digestive tract that includes the caecum and the colon; comprises approx. 65% of the digestive capacity of the horse’s gut and is the main site of microbial fermentation of fibre.

Insulin resistance
Failure of a normal amount of insulin to exert its physiological effect of promoting the uptake of glucose into cells from the blood.

Imune system
The body’s defence against infection.

Immunoglobulins (Ig)
Another name for antibodies. Different types of immunoglobulins are identified by letters e.g. IgA, IgE, IgG.

Insulin resistance
Failure of a normal amount of insulin to exert its physiological effect of promoting the uptake of glucose into cells from the blood.

Insulinaemic response
The increase in insulin seen following a meal in response to rise in blood glucose and amino acids.

Nutrients that are essential to the health and wellbeing of the horse but are only required in very small amount e.g. vitamins, minerals, trace elements

Commonly considered to result from a failure of bone formation, leading to retention of cartilage in the bones of growing horses.


Osteochondritis dissecans
(OCD) Commonly considered to be a manifestation of osteochondrosis; involves a lesion on the surface of a joint associated with the formation of a cartilage or cartilage and bone flap.

Non-structural carbohydrate digested in the main in small intestine by digestive enzymes and broken down to glucose. Essentially, the white part of cereals when the outer husk or bran is removed.

Synchronous diaphragmatic flutter (“Thumps”)
This occurs when an imbalance of electrolytes affects the nerve that controls the diaphragm, causing the diaphragm to contract in time with the heart, leading to a “hiccup-like” effect. This condition is most common in endurance horses.

Subchondral bone cysts
Usually result from cracking and fissuringof thickened cartilage often at the centre of the joint (unlike OCD where it tends to be at the periphery) leaving and entrance for synovial fluid and thus creating a cyst.

White blood cells that identify and destroy diseased cells or trigger antibody production by B-lymphocytes.

Volatile Fatty Acids (VFAs)
End product of the microbial fermentation of fibre in the horse’s hindgut; they provide a source of energy

live yeast prebiotic that helps to maintain a healthy hindgut by supporting fibre digestion.