Deciding what to feed your horse can be tricky and the terminology used doesn’t make things any easier!


An antioxidant is a molecule that inhibits the oxidation of other molecules. Iron turning rusty is an oxidative reaction, and oxidation can damage cells, tissues and potentially the very molecule of life – DNA.

In humans, oxidative damage has been shown to contribute to cancer, heart disease and is even involved in the aging process. Antioxidants are molecules that can terminate these dangerous chain reactions. They include vitamin E, vitamin C, selenium and polyphenols, which are natural compounds found in plants. This is why we should eat our five a day!

Amino Acids

Amino acids are the building blocks of protein and there are 25 in total. Horses can synthesise 10 of these, but the other 15 must be supplied by the diet and are known as essential amino acids – eg, lysine. Proteins are broken down to amino acids during the process of digestion.


Fibre is a structural carbohydrate that is vital for keeping horses’ digestive systems healthy. The main sources of long fibre in a horse’s diet should come from sources such as grass, hay or haylage, and should take up at least 50% of the diet, even in competition horses.

Micro and macro minerals

There are two types of minerals – macro minerals, which are needed in relatively large quantities (grams per day), and micro minerals or trace elements, which are only needed in tiny quantities (milligrams per day).

Non-structural Carbohydrates (NSC)

Carbohydrates are split into two groups depending on their chemical structure – structural and non-structural carbohydrates. Non-structural ones include starch and sugar that can be broken down by the horse’s own enzymes, unlike structural carbohydrates that need to be fermented by the bacteria present in the hindgut.

Omega-3 Fatty Acids

Omega-3 fatty acids are fats typically found in plant and marine oils. Although not extensively researched in the horse, omega-3 oils are thought to have some health benefits in humans, including supporting the immune and cardiovascular systems, and it’s possible that it could have similar benefits for horses.


A probiotic is a live yeast or bacteria that is introduced to the gut to help promote ‘good’ bacteria and maintain gut health.


A prebiotic is a fermentable food source that is utilised by ‘good’ bacteria in the gut, helping to support a healthy microbial population. FOS is an example of a prebiotic.


Proteins are compounds that consist of a chain or sequence of amino acids. Protein is needed in order to synthesise enzymes, immune cells and cartilage, and to help build and repair muscle.

Horses in light work require 8-10% in the total diet, 10-12% for older horses, breeding horses or those in heavy work and 14-16% for a young, growing foal. Contrary to popular belief, protein does not cause excitability or swelling in legs.


This is the sugar you put in your tea! Sucrose is a disaccharide sugar consisting of fructose and glucose. Sucrose is the main sugar found in grass and is used for energy within the body.

Water-soluble Carbohydrate (WSC)

WSC refers to carbohydrates that are soluble in water and they are primarily sugars, such as fructans found in forage.


This is a type of complex polysaccharide found in plant cell walls, and is a component of dietary fibre.