Fibre is the most important element of a horse’s diet, providing up to 70% of their energy needs. But what actually is fibre, and how does it work?
Fibre refers to the carbohydrates that make up plant matter and is found in two different forms.
Structural or complex carbohydrates
Structural or complex carbohydrates are nutrient-dense foods composed of sugar molecules that provide digestible energy. These carbohydrates make up the cell wall of plants, which includes cellulose and hemicellulose.
Most mammals, including horses, can’t digest these fibres and therefore rely on microbial gut bacteria to help with digestion. This process is called fermentation, where cell walls are broken down in the caecum and colon into volatile fatty acids (VFAs) to produce sustainable energy.
Non-structural carbohydrates (NSC)
Non-structural carbohydrates (NSC) are soluble sugars, such as glucose, fructose and sucrose, and starch, which are stored in plant cell walls. When the horse chews, these are released as the cell wall is broken down. These carbohydrates can be digested in the small intestine.
How can these vary?
The maturity level of a plant determines the level of structural or non-structural carbohydrates present in the cell walls.
Spring grass, or early cut hay/haylage has higher levels of non-structural carbohydrates and therefore higher levels of sugars and starch. More readily digestible, these NSCs are suitable for horses and ponies that require additional calories, such as those in harder work, broodmares, and youngstock.
Older, more mature plants or late cut hay has higher levels of structural carbohydrates and therefore less readily digestible energy. This is more suitable for horses and ponies who require less calories, such as those on restricted diets, or with metabolic syndromes.
The importance of fibre
Fibre is vital for horses to maintain a healthy digestive system and provide energy.
Benefits of fibre:
· Digestive health and motility: fibre digestion allows the digestive tract to keep moving, reducing the risk of impaction colic. It also serves as a reservoir for water in the gut, aiding hydration.
· Stomach acid buffering: when horses chew, the saliva that is produced and swallowed can neutralise stomach acid, reducing the risk of gastric ulcers.
· Hindgut fermentation: fibre is broken down to produce VFAs, a primary, healthy source of energy.
· Stimulation: as obligate herbivores, horses have developed to graze for long periods. High-fibre diets satisfy their innate need to chew, reducing boredom and lessening the risk of the development of stereotypic behaviours.
· Warmth: hindgut fermentation is the main way in which horses generate internal heat.
· Slow-release energy: the VFAs that non-structural carbohydrates provide are a form of consistent, slow-release energy that can reduce blood sugar spikes and associated ‘excitable’ behaviours
How can you provide fibre in the diet?
The horse’s main dietary intake should consist of fibre, which should always be offered at no less than 1.5% of bodyweight per day on a dry matter basis.
Fibre is most often provided in the following forms:
· Pasture
· Forage in the form of hay or haylage (and occasionally straw)
· Chaff, made from straw, grass or alfalfa
· Molassed or unmolassed sugar beet
Take Away
Providing fibre in the diet is crucial for overall health and nutrition, and can be provided in many different ways. When choosing a type of fibre for your horse, it is important that you take individual requirements into account, as some fibre types suit some horses more than others.
If you have any questions or queries regarding your horse’s diet, remember, our specialist nutritional helpline is on hand 9-5 Mon-Fri on 01604 263002 or at info@sciencesupplements.co.uk
Written by Anna Jones BSc (Hons) Equine Science - Customer Care & Marketing Associate