Oil as a safe energy feed for horses

By Amanda Grimmett (BAgSc(Hons)).

The modern, domesticated horse lives in an environment quite dissimilar to the evolutionary one. This, coupled with paddocks and stables that restrict the grazing of quality pasture, can make safely meeting horses energy needs quite a tall order.

The grain solution and the problem with it:

Traditionally, horse diets have often included large quantities of grain (ie. starch) in an attempt to sate horses energy needs.  However, horses have a limited capacity to digest starch and a high starch intake can result in starch overload into the hindgut.  A number of metabolic disorders are associated with high grain diets, such as tying up, laminitis, colic, and ?hot' behaviour.  Advances in feed processing technologies have reduced the risks associated with high starch feeding, but not altogether eliminated them.

Alternative energy sources:

So what else can provide energy to working horses safely?  Long fibre present in roughage feeds (ie. hay, pasture), is digested by microbes in the horse's hindgut.  Volatile fatty acids are released from this digestion, which supply energy to the horse.  Although vital and irreplaceable in the equine diet, long fibre alone is often insufficient to meet energy demands of performance horses.  Dietary proteins can also be used to some extent to yield energy.  However, protein is not an efficient source of energy and it is better used to meet amino acid requirements rather than supply energy.

Oil as an energy source:

Dietary oil is a useful source of energy for horses.  Oil is more energy dense than starch or protein and once horses are adapted to it, oil is well accepted, digested and metabolised. Because horses are not accustomed to consuming oil in their diets, a gradual introduction to dietary oil is essential.  However, horses readily adapt to diets higher in oil and utilise this in the form of fatty acid oxidation during aerobic exercise. (Aerobic exercise is slower/submaximal exercise, which may require stamina).

The sensible inclusion of oil in equine diets does not carry with it the metabolic risks of high starch diets.  Studies show that oil inclusion rates of up to 10% do not adversely affect digestibility of other nutrients and in some cases appear to actually increase fibre digestibility in the hindgut.  Compared to other sources of energy feeds, oil does not produce as much heat waste, which may be of benefit to horses living in hot climates.

Oil sources:

There are a variety of oil sources available that are suitable for inclusion in equine diets.  Oil sources range from pure oils to feedstuffs such as copra meal which are rich in oil.  In practical feeding terms, the oil source you chose for your horse must be palatable, not rancid and must be introduced into the diet slowly, in a stepwise manner.  Fed sensibly, dietary oil can certainly help to meet the energy challenge for the modern horse.