Fibre, (also known as ‘structural carbohydrate’, bulk, roughage and crude fibre) is made up of several different types of carbohydrate, and is essential in the horses diet. It cannot be digested in the small intestine, instead it is fermented in the hindgut. It therefore keeps the horse fuller for longer, and provides a source of slow release energy.
- Like humans, horses do not have the necessary enzymes to break the fibre down. Instead, the fibre is fermented in the hindgut by billions of bacteria that take up residence there. In return for giving the bacteria a home, the bacteria provide the horse with (most) of the energy (calories) held in the fibre on a little-bit-at-a-time basis. For this reason, fibre is considered a source of slow-release energy.
- The horses gastrointestinal tract is a MASSIVE organ, and it must be kept full. This, again, is where fibre comes in, it provides the bulk of the horses diet, and keeps this great hulk of an organ full.
- Lastly, fibre can mimic the action of a sponge, and absorb water and store it until the horse needs it. So, as we have seen, fibre is incredibly important, and should make up the largest part of a horses diet, but from where can it be obtained?
Fibre is found in significant amounts in the feeds listed below:
- Hay, Haylage and chaff
- Pasture (Grass and legumes)
- Oat hulls
- Sugarbeet pulp
- Lupin, sunflower and soybean hulls
If a horse doesnt get enough fibre in their diet, major problems can occur, such as;
- Colic – If a horses gastrointestinal tract is not kept full, it is prone to twisting, and moving in abnormal ways which are usually inhibited when it is full of fibre.
- Diarrhoea – Low fibre diets cause water moves too fast through the gut, and it is not absorbed, or slowed down by fibre. This results in loose sloppy manure, which reduces gut efficiency and can cause electrolyte deficiencies.
- Dehydration – If a horse has a low fibre reserve in the gut, they wont have a large reserve of water available, and for that reason if they sweat profusely or are away from water for an extended period of time, they become dehydrated
- Lack of Energy – Fibre provides slow release energy, and and a lack of fibre, causes a lack of energy, which results in fatigue and weight loss.
- Boredom – Not having access to enough fibre fills hour which would have been spent eating, with boredom. This causes horses to develop vices such as weaving, box walking, cribbing, windsucking and dirt eating.
- Constant Hunger – The enormous gastrointestinal tract will not be full, and therefore the horse will be constantly hungry. This will result in bad habits, such as dirt licking/eating and eating poisonous plants, or those that are not usually considered palatable.
- Sand Colic – Boredom can cause sand licking/ eating, and this dirt has no place in the horses digestive system. This can cause sand colic from blockages and impactions. Another way for this dirt to enter the system is if the horse is grazing on loose or sandy soil, and vacuuming large amounts of dirt with the (little) food it does manage to obtain.
So, as we have seen, fibre is essential in the horses diet, but how much should be fed?
Fibre should be fed in the horses diet at a bare minimum of 1% of the bodyweight. This would mean 1 kg of fibrous feed per 100kg of bodyweight, thus a 500kg horse would be fed 5kg of forage. This would be adequate for a cob as they do not need so many calories to gain or maintain weight, and for a horse with EMS, but a warmblood or thoroughbred would ideally need 2-2.5% their bodyweight.
At least half the fibre in the horses diet should be long ‘stem’ fibre, namely, grass and hay, as this is what the gut is naturally built to cope with. It takes longer to eat, keeping them happier for longer, and it makes them chew more, which stimulates saliva production, which, in turn, helps to keep the gut healthy.
