When considering appropriate food for horses, there are many factors which affect a horse’s individual requirements. These include, age and health, bodyweight and general condition and amount of work the horse does.  Also, is the horse able it to source feed naturally in its environment and is this plentiful or is food rationed and controlled by the owner or trainer?

Nutrients are obtained from carbohydrates, fat and protein. Horses also require vitamins, minerals and a plentiful source of fresh, clean water. There are simple calculations which should be used to establish the correct amount of feed based on each horse’s individual requirements.

Firstly, the total amount of food a horse needs on a daily basis depends on its bodyweight and condition.  The easiest way to measure a horse’s bodyweight, if appropriate scales are not available, is to use a commercial weigh tape.  These can be bought from specialist horse feed suppliers.  The weigh tape is placed around the horse’s barrel, just behind the elbow.  It will give a fairly accurate body weight reading which can then be used to work out the amount of food.  

Horses generally need to be fed between 1.5% and 3% of their body weight in food, on a daily basis.  A native pony who is a ‘good doer’ may only need 1.5% of its bodyweight in feed while a rangier, naturally lighter thoroughbred, for example, may need closer to 3% of its bodyweight.

As an example, a 500 kg horse will need between 7.5 kg and 15 kg of feed a day.

Once an appropriate total amount of feed has been calculated, the amount needs to be split into a roughage ration and a concentrate ration. This calculation depends very much on the type of work the horse does.

For example, a 500 kg horse, in good condition with no health problems and doing light work (say 1 hour of work each day in walk, trot and canter) will need a total daily ration of 10 kg of food (based on 2% of its bodyweight).  This amount is split into 8 kg of roughage and 2 kg of concentrates.

Roughage (Forage)
Grass is the most common forage food and will provide the horse with essential nutrients including carbohydrates, proteins and vitamins.  Minerals are also available to horses from grass; however the quantity and sort vary depending on soil quality and location. Grass quality also changes throughout the seasons. So for example after long growing period throughout spring and summer, grass will contain more fibre and fewer nutrients.

Hay or dried grass (dried to 5-15% moisture) is also commonly fed as forage. This is normally lucerne or grass (it can be greener depending on the length of drying time).  The quality of hay feed is extremely important and hay should never be mouldy or dusty, which can lead to digestive upsets and respiratory problems. The hay quality can be affected by the way it is stored, what species is used and when in the harvesting season it was originally cut.

Concentrate feeds provide additional energy and protein in the diet and are particularly important for horses in hard work, young growing animals and pregnant mares. Concentrates can be divided into two groups: straight cereal grains or manufactured compound feeds e.g. mixes/pellets/cubes. Rationing of concentrates should be carefully considered as otherwise the horse may experience stomach upset and changes in behaviour. The horse has a relatively small stomach, so no more than 2.5 kg of concentrates should be fed at any one time – this should be also be adjusted according to the size of the horse. When introducing new concentrates into the diet, introduce small amounts at a time to the horse’s existing ration.

The most common straight cereal grains fed to horses are oats and barley:

  • Oats are a natural whole food for horses that provide lots of energy, as well as helping to condition the horse’s coat and hooves. They do not provide all the nutrients required however and additional mineral and vitamin supplements may also be needed.  The amino-acids, lysine and methionine, are also worth adding as their concentrations are low in oats. Oats can have ‘heating’ effects for some horses, resulting in changes to temperament and ‘rideability’, so introduce slowly to prevent problems occurring.

  • Barley is more energy dense than oats. Again certain minerals are lacking, the ratio of calcium and phosphorus in barley is the opposite of what is required by horses so supplements are normally recommended. Additionally vitamins A and D are lacking from barley so vitamin supplements are essential. Barley is particularly useful to put additional body weight onto an underweight horse.

Additives in the diet include mineral supplements such as salt. There are also innumerable vitamin supplements, enzymes and amino acids as well as some chemical additives including pellet binders and mould inhibitors for example. Some additives are there for the specific purpose to benefit the health and nutrition of the horse, whereas other additives are hidden within certain foods and you may not even realise they are there.  

The effective use of supplementation in feed is complex and should not be oversimplified.

Providing clean water is absolutely essential to a horse’s health. Without water, a horse will die. The regulation of internal body temperature, all chemical reactions, all sweat and urine production and movement and removal of toxins in the blood, all require water. Horses can drink up to 70 litres per day, so a fresh and constant supply should be available.