Feeding the working horse

Date: 01 Sep 2002


If a working horse has been bred for the job, is well trained and managed, is in good health and lives in a suitable environment, then nutrition will be the main factor influencing its performance.

Generally, horses undergoing only limited athletic activity or light work are fully nourished by good quality pasture. However, pastures vary greatly in nutritional value. At times, particularly in late summer and in winter, working horses might not get enough nutrition from grazing, and will need a supplement.

If you intend to feed a supplement you will first have to assess the nutritional value of the paddock feed. You will then have to assess the amount of work being done by the horse and the nutritional needs and performance of the horse before you can formulate an ideal ration. The supplement will have to be worked out for each horse in work.

Supplementary feeding

While pasture quantity and quality can be measured, experience is usually the best guide as to when and what supplements may need to be fed.

As pastures hay off in summer, their digestibility declines, and even though pasture quantity may appear adequate, its low digestibility means that the horse may not be obtaining sufficient nutrients. Provision of a supplement of high quality hay or grains may be adequate.

Feeding a supplement should be aimed at providing that part of the horse’s nutritional needs not available from the grazing. The supplement should not be a substitute for available grazing.

Quite often a horse in work does not have the opportunity (time) to graze, and therefore will require hand feeding.

Full hand feeding

When horses do not have access to grazing, a well-balanced ration which provides energy, plus protein, minerals and vitamins, needs to be supplied.

The energy requirement is the most important part of the diet of a working horse, the amount required depending on the weight of the horse and the amount of work being done. The amount of energy required is expressed in units of megajoules (MJ), and the amount of energy in feeds is expressed as megajoules per kilogram of dry matter (MJ/kg DM).

The protein requirement of a horse is expressed as a percentage of the total feed intake, mature horses requiring a level of 10% protein. It is generally assumed that any additional protein requirements for work are not great and can be met by the extra intake of the same diet used for maintenance.

When grazing is adequate, the addition of minerals and vitamins to the diet is not usually necessary. However, when hand feeding grain diets in the absence of grazing or lucerne hay or chaff, a daily supplement of 35 g of limestone should be provided. The provision of a balanced mineral/vitamin supplement may also be necessary, particularly if roughage quality is poor.

Salt should be supplied freely to working horses because considerable quantities are excreted in sweat. The provision of salt blocks or rock salt in feed boxes will help ensure adequate intake.

Feeds for horses

Two basic types of feeds are available to provide the nutrient requirements of the horse. These are:

  • roughages—feeds that have bulk but the percentages of digestible nutrients are low, for example hays, crops and pastures;
  • concentrates—less bulky feeds with higher percentages of protein or energy or both, for example grains, grain by-products and protein meal.

Tables outlining the average composition of feeds are available. A comparison of some of the more commonly used feeds is given in Table 1. These are only average compositions. Concentrates are usually labelled with their protein level. Check this, as the protein level varies between feeds.

Table 1. Comparison of the more commonly used feeds (‘as fed’)
Feed Crude protein (%) Metabolisable energy (MJ/kg DM)
Soybean meal 50 12
Peanut meal 42 11
Cottonseed meal 28–43 10.5
Skim milk powder 36 12.8
Linseed meal 30–35 11.5
Lupins 28–35 13
Bran (oaten) 8 9
Lucerne hay 15–20 8.5
Oats 10 12.5
Sorghum 9 13
Barley 11 13
Maize 9.5 13.5
Pasture hay 11 8.5
Wheaten hay 6 8
Oaten hay 5.8 9.3

Pasture, legumes, cereal chaffs and hay are the most common roughages fed to horses, but quality is variable. Only the best quality hay, free from mould and dust, should be used. Oats is the safest and best of the grains, but other grains can be substituted for up to 50% of the oats in the ration. Protein meals, if required, are lupins, soybean meal, cottonseed meal, sunflower meal, linseed meal and peanut meal.

Vegetable oils have been found to be useful as a substitute for some of the grain in the ration if grains cause the horse to become excessively excitable. As a guide, 250 mL (1 cup) of oil provides the same amount of energy as 2.5 kg oats, and this is generally sufficient. No more than 500 mL of oil should be fed per day, as grain intake will decrease if oil is fed above this level. Oils need to be introduced to the horse gradually until the horse gets used to the taste, and should be added to the mix just prior to feeding to avoid rancidity. Vegetable oils also have the advantages that they reduce dustiness of feed and, because they have no fibre, do not cause heating or contribute to founder.

Designing the ration

The first step in designing a ration is to determine the weight of the horse and the amount of work it is doing. (As a guide to the weight of a horse, the approximate weight of a pony 10–12 hands high is 250–300 kg, and of a light hack 14–16 hands high is 400–500 kg.) The amount of energy required to be fed can then be determined from Table 2.

Table 2. Energy requirements for horses at various levels of work
Weight (kg): 400 500 600
Energy (MJ) required for maintenance per day: 58 68 79
Additional energy (MJ) required per hour for:
Walking 0.84 1.05 1.26
Slow trotting, some cantering 8.4 10.5 12.6
Fast trotting, cantering, some jumping 21.0 26.2 31.4
Cantering, galloping, jumping 38.5 48.1 57.8
Strenuous activity (polo, racing at full speed) 65.3 81.6 97.9

Source: NRC Tables—Nutrient Requirements of Horses

Horses will, if allowed, eat 1.5–2.5% of their body weight in dry matter per day, depending on the type of food and on the individual horse. This means that a 500 kg horse could eat up to 12.5 kg of dry matter per day.


A 500 kg horse doing 2 hours of slow trotting with some cantering, and 1 hour of fast trotting, galloping and jumping, will need:

Maintenance 68.0 MJ
Slow trotting 2 × 10.5 = 21.0 MJ
Fast trotting 26.2 MJ
Total: 115.2 MJ

In formulating a suitable ration for such a horse, the ingredients selected will be on the basis of availability and cost. As a guide, the amounts of roughage and concentrate are given in Table 3.

A suitable ration for the 500 kg horse in this example could be:

7 kg lucerne chaff: 7 kg × 8.5 MJ ME/kg = 59.5 MJ
5 kg oats: 5 kg × 12.5 MJ ME/kg = 62.5 MJ

122 MJ

Remember that these calculations are made on a ‘dry matter’ basis and need to be converted to an ‘as fed’ basis when determining how much to feed. For example:

5 kg oats at 90% dry matter = 5 ÷ 90 × 100

= 5.5 kg fed

As a guide to formulating the ration, Table 3 gives approximate amounts of roughage and concentrate required for fully handfed horses doing varying amounts of work.

Table 3. Roughage and concentrate requirements of fully handfed horses
Type of work Feed per 100 kg liveweight
Roughage (kg) Concentrate (kg)
Idle 1.5 Nil
Light (2 hours/day) 1.25–1.5 0.5–0.75
Medium (2 hours/day) 1–1.5 1.0
Heavy (4 hours/day) 1.0 1.0–1.5

Feeding management

  • Treat each horse as an individual, learn its feeding habits, and adjust rations accordingly.
  • Feed and water according to a regular routine.
  • The daily ration for working horses should be split into at least three feeds per day, with half the ration fed as the evening feed.
  • When fully hand feeding, feed a quarter of the concentrate requirement at each of the morning and midday feeds, and feed the remaining half at night.
  • Reduce the amount of concentrate by 50–70% on days when the horse isn’t worked.
  • Make any changes in the ration gradually over a period of 10–14 days.
  • Keep feed and water troughs clean, and remove leftovers.
  • Measure feeds by weight, not volume.
  • Mix feed carefully and only in sufficient amounts for each day’s feeding.
  • Do not allow a hot horse to drink large quantities of water. Allow the horse to drink only 2–4 L, then let it cool before allowing free access.
  • Avoid working the horse on a full stomach. Allow at least 2 hours for digestion.
  • Control parasites with a regular drenching program.
  • Inspect teeth periodically and have problems corrected by a veterinarian or competent equine dentist.
  • Some horses get ‘fizzy’ on grain. If this happens, reduce the grain ration and try supplementing with vegetable oil or rice-based supplement.

Author: Bruce Mackay