Published in European Trainer, January - March 2018, issue 60.
Oil is a regular addition to modern racing diets, either by feeding a high oil-containing racing feed or through extra addition of liquid vegetable oil. Research over the years has shown that oil is palatable to horses and digested very well, and that there is little difference in digestibility between the main types of vegetable-based oils used.
Oil that is integral to feed ingredients, such as that found in rice bran, linseed, naked oats, soya, etc., may have a marginally lower digestibility, as this will depend on how digestible the encapsulating matrix is to the horse. However, in the main both free oil and integral oil is well tolerated and digested in horses.
In a natural environment, horses can easily consume between 2-3% of their body weight as dry matter from pasture. Oil has always been a natural part of the horse's diet, as grass contains about 2-3%, which may seem low but can provide the equivalent of 200-400mls of oil per day. Other forages, such as hay, haylage, and chaff, will also contain oil at a similar level on a dry matter basis.
Horses can tolerate up to 20-25% of their total energy intake coming from oil, and this has been exploited successfully....