Q: I am confused as to which type of oil I should be adding to my horse’s feed. So far, I have been feeding about half-a-cup of sunflower oil a day, but I’ve been told that corn oil is more digestible. I have also heard that some horses are allergic to rapeseed oil, which would seem to rule out blended cooking oils. Please can you give me some advice?

Christine Smy, an independent nutritionist, answers: “When choosing an oil, it is important first to determine the reason for feeding it. If it is for the essential fatty acid content, buy unprocessed oil that hasnot had heat treatment, which can destroy the essential fatty acids. This tends to rule out supermarket products such as sunflower, corn and vegetable oils.

However, if you are just feeding for body condition, supermarket oils are fine. Feed a pure oil, such as sunflower or corn oil, rather than a blended oil, such as vegetable oil, as some horses can have bad a reaction to these.

Although the taste of pure oils varies little, your horse may develop a preference for a particular type.

If you are after the benefits of essential fatty acids, you should buy unprocessed corn or soya oil from your local feed merchant. You can buy these in large quantities relatively cheaply. However, it can be a false economy as you may end up throwing away oil if it turns rancid – which tends to happen in hot weather.

The amount required by your horse will vary according to his exercise regime and the objective of adding oil to the diet. Start with a tablespoon three times a day and increase this gradually until you are happy with the results.

A good level of oil would be around 150g a day (around half a cup) for leisure horses and 300g (a full cup) for performance horses.

The benefits of oil

Oil is added to the diet:

  • To provide essential fatty acids (EFAs), which the horse is unable to process himself and are particularly useful for the production of hormones
  • To add body condition. Oil is very energy dense, having around three times the number of calories as carbohydrate. As it is easily digested and absorbed, it is an excellent way to maintain weight.
  • As an energy source. Oil is a very accessible source of muscle fuel for horses, particularly those in endurance-type work. Due to its relatively slow breakdown, it’s ideal for horses that tend to ‘fizz up’ or tie-up on cereal starch
  • To boost coat condition in healthy horses
  • To relieve stiff joints and arthritis in older horses. However, oil levels should be reduced if the horse has liver problems.