Energy cannot be created or destroyed, it can only be changed from one form to another – Einstein

Now Einstein may have been speaking about thermodynamics, but it applies to nutrition as well. Energy is an important nutrient for all horses as too little, or, too much can cause problems.

If you give your horse more energy in the wrong form, it may not be used for the job that you intended and according to the above statement has to be used for something!

That 'something' is generally fat storage or explosive behaviour, it all depends on what you and your horse need.


Energy is required by your horse for maintenance.

Energy for maintenance is just as it sounds – the amount of energy required to keep the horse in its current condition with no weight loss or gain (energy is required for all the various processes in the body).

Extra energy is required for any work the horse does, growth or lactation etc.

All horses are different in their maintenance requirements and this is affected by genetics, size, age, environment and temperament. Energy for work also differs according to the type of horse that you have.

Different feeding stuffs provide different amounts and types of energy, knowledge of the different energy sources available is important to ensure that you select the correct feeding regime for your horse and its requirements.

Energy sources

Energy can be supplied to the horse from three main sources; fibre, starch and oil/fat.

In severe conditions energy can be provided from protein but the metabolic path ways are not efficient and can produce some nasty by-products.

Fibre and 'super fibres'

The most important energy source to any horse, be it performing or otherwise, is fibre.

This not only keeps the horse’s gut healthy by helping to prevent complications such as ulcers and colic, it also can provide the majority of leisure horses with the majority of their energy requirements.

In the past, fibre would not have been considered as being important to performance but attitudes have changed and many horses perform at high levels on a mainly fibre diet.

Alfalfa is a great energy source providing as much energy as your average cool mix. Super fibres, such as beet pulp and soya hulls, are now widely used in horse feeds, and provide highly digestible fibre. (80% and 75% respectively).

The type of energy provided from fibre is slow release energy so it is ideal for horses that have a tendency to be fizzy or exuberant, it is also crucial for horses from which stamina is required (e.g. eventers, and endurance horses).

Forage in the form of hay,

haylage and grass is very important to the horse and should contribute an absolute minimum of 1.5% of the horses body weight but preferably more like 2%.

The horse is a trickle feeder and as such the digestive system is healthiest and most efficient when it is almost constantly occupied with forage. Ad-lib forage should be the first energy source provided to your horse with anything else required being added to his diet beyond this. Most horses in light work will do very well on just forage and chaff alongside a mineral supplement or balancer pellet to fulfil their trace element and vitamin requirements.


Starch provides quick release energy and, as such, has traditionally been fed to working horses and horses that are required to perform bursts of speed. Cereals are the largest source of starch; oats, barley, maize.

Cereals play an important role in horse feeds, particularly in feeds designed for horses that are working at light-medium level or above.

They provide fast release energy and are therefore important in diets for horses that require bursts of energy or those that require a little more oomph. Care must be taken when feeding cereals however, as the horse’s digestive system can only handle so much starch at once.

The stomach of the horse is where starch digestion should occur and any overspill due to overlarge meal sizes (eg more than 2kg concentrate) means that starch will pass into the large intestine where fermentation will occur and the good bacteria population will be upset and allow proliferation of bad bacteria. Ironically this upset in the gut balance will mean that the horse is unable to digest and make use of the energy provided to it by its well meaning owner. Ensure that meal sizes are kept small.

Oats have been a much maligned energy source, with an unjustifiably bad reputation. In actual fact oats are the easiest cereal for the horse to digest and consequently the least heating.

Whole oats also provide good levels of fibre and oil, and are the only cereal that can be fed to the horse unprocessed. Maize is the most heating closely followed by wheat and barley. Cooking these cereals does improve their digestibility however and consequently these should be fed in this form. As already mentioned cereals provide fast release energy and because of this are an important constituent of diets for working horses. Starch is broken down by the body and stored as glycogen in the horse’s muscles for future use.

Fats and oils

Most people are very aware of the benefits of feeding oil to their horse as an energy source, there have been countless article written on the benefits of this in the horsy press. Fat is a slow release energy source and as such is ideal for feeding to those with a slightly fizzy temperament to provide the energy required for performance without the potentially explosive side effects of too many cereals.

Oil provides 2.25 times more energy than the equivalent weight of cereal and so is also ideal for increasing the nutrient density of the diet. In other words a lot of energy can be provided in a small amount for fussy eaters, poor doers or hard working horses.

The use of oils in feeds for performance horses also has other benefits. One of these is the fact that there is a glycogen sparing effect when high oil diets are used. This basically means that the fat stores are used up when the animal is performing aerobically at slower speeds and the glycogen stores are reserved for the fast anaerobic sprint work.

This means that there is more fuel left in the tank and less muscle damage post hard exercise due to lower levels of lactic acid accumulation in the muscles. It must be remembered that when high levels of oil are fed extra vitamin E should also be fed, with the current recommendations being an extra 100 IU of vitamin E per 100ml of oil fed.

Different sources for different horses

There are many ways of providing energy to your horse. Use good quality fibre sources (including super fibres) and oil to provide energy where possible, with cereals being used to provide a bit more oomph when required and in hard working animals.

Look for feeds with a high oil content (5% plus) and fibre content (eg. Harbro Country Horse and Pony Nuts and Mix and Conditioning Cubes for harder working animals) and select a feed according to the level of work your horse is doing. As always, if in any doubt, or you would like any advice on how best to feed your horse, please consult a reputable nutritionist.