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Fats or oils in horse feeding

There is a growing interest in the use of oils in horses’ diets due to the benefits of using fewer concentrates to increase caloric intake, increased reproductive efficiency and energy during exercise as well as better modulation of the immune response. Let’s take a closer look at which fats and oils are most appropriate for the horse and how to use them for maximum benefit. There is a growing interest in the use of oils in horses’ diets due to the benefits of using fewer concentrates to increase caloric intake, increased reproductive efficiency and energy during exercise as well as better modulation of the immune response. Let’s take a closer look at which fats and oils are most appropriate for the horse and how to use them for maximum benefit.

Fats or oils in horse feeding

What are fats? Which ones are part of the horse’s diet?

Fats can be animal or vegetable; those intended for horses are unsaturated fats, usually in the form of oils, as they are in liquid form at room temperature. Fatty acids are fundamental components of lipids and include the most famous Omega 3 and Omega 6 which are defined as ‘essential’ as they cannot be synthesised by the body. Their intake is essential, as they are the precursors of molecules and substances that modulate the immune system and influence the cardiovascular system.

The sources of fat for the horse in the basic diet are hay and feed. Although hay and pasture have a low total fat content, typically less than 5%, most of the fat is omega 3 fatty acids, whereas the fat in cereals and horse feed is mainly omega 6. Unbalanced diets with little hay and high amounts of cereals shift the ratio in favour of omega 6, with bad consequences for the body.

Fat metabolism in the horse:

Once a horse ingests fat or oil, enzymes (called lipases) in the stomach begin to break it down. Most fat digestion takes place in the small intestine, particularly in the duodenum and jejunum. After absorption, fats move to the liver, adipose tissue or elsewhere, as needed, for storage or use. Fats that are not absorbed in the small intestine travel to the large intestine and colon and are excreted in the faeces.

How much fat can the horse digest?

In several studies researchers have found dramatic differences in the digestibility of various fat sources in the horse’s diet. Fats from forages appear to be 55% digestible, whereas oil fats are 100% digestible.

How much oil can I give to provide a good amount of fat?

If we give 70-80 ml of oil per day it will have a beneficial effect on the coat, this amount provides only 2.5% of the Digestible Energy (ED) required by a horse in moderate work. Larger amounts of oil are required for more demanding exercise. For example, a horse engaged in strenuous exercise should have a ration of 400 grams (about 450 ml) of vegetable oils per day. These amounts are difficult to achieve as oils are an expensive source of energy, costing twice as much per calorie as cereals.

Benefits of a high fat ration for the horse

    • Fat is important for the absorption of fat-soluble vitamins (A, D, E, K). Extremely low-fat diets have the potential to reduce the absorption of fat-soluble vitamins, as seen with the decrease in vitamin E levels in ponies fed an extremely low-fat diet.

Fats are important for reproduction, the role of omega 3 in fertility has been known for some time in stallions and mares both for heat induction and to improve the fat content of milk during lactation, which after the first 30 days declines as much as the protein content. In this situation, it is useful to use a complementary feed such as Omega Energy.

  • Fats are useful for horses below ideal body condition; they meet the need for weight gain by avoiding excess grain and starch.
  • Managing conditions where there are alterations to the immune system and normal skin, joint or gastric physiology.

Fats are useful in nervous horses Some researchers, such as Holland et al, have suggested that replacing typical grain-based diets with some fats can potentially reduce reactivity in horses. According to one study, foals fed a diet containing fat and fibre (such as Fat Fiber) also appeared less stressed and reactive after weaning than those fed a traditional grain-based feed.

Long-term fat supplementation combined with appropriate training results in lower glucose and glycogen expenditure, which may delay the onset of fatigue during endurance exercise. A recent study conducted by Kentucky Equine Research on Arabian horses demonstrated just such an energy-saving effect. After ten weeks of fat supplementation (10%) the horses used 30% less glucose and muscle glycogen during an endurance test exercise.

In the endurance horse, supplementation of at least 8% fat in the diet appears to keep blood parameters such as glucose and free fatty acids in range. With this type of diet, the researchers also found lower lactate levels in horses performing low-intensity exercise.

How long does it take to see these physiological changes associated with eating fat?

Nutritionists say a minimum of 10-12 weeks, although some researchers have reported changes in 3-5 weeks. Consistent nutrition is the key to seeing results.

Which oil to choose as a source of fat?

No source of Omega 3,6 is bad for the horse, but some sources are certainly better than others:

  • Flaxseed and Soya Seed Oil: these provide essential fatty acids with the best omega 3 to omega 6 ratio. Flaxseed oil is the most bioavailable, with an Omega 3/6 ratio of 4:1.
  • Flax or Chia seed oil? Chia seeds are superimposable on flax seeds in terms of Omega 3 essential fatty acids: 58% for flax and 60% for chia. Flax is more energetic because it provides 45% fat compared to 35% for chia.
  • Rice oil: contains mainly omega 6 and is characterised by the presence of phytosterols and gamma oryzanol.
  • Corn oil is certainly the most palatable and is an important source of calories. It improves coat appearance but is not beneficial to the horse’s immune system as it undermines the omega 3/omega 6 balance. Constant supplementation of the diet with corn oil can promote allergic and inflammatory problems.
  • Sunflower Seed Oil: as with Maize Oil very rich in Omega-6 but poor in Omega-3.
  • Cod Liver Oil: Animal fats tend to be more saturated than vegetable fats. Horses generally digest vegetable oils better than animal oils, so it is preferable to avoid the latter, also to follow the nature and physiology of the horse, which is a herbivore. In addition, this oil has an unpleasant smell and is not appreciated.

It is best to choose oil-based products with the best omega 3: omega 6 ratio, mechanically extracted such as Oil Performance. It is important to avoid chemically extracted products that may contain pollutants that can then damage the body of the horse, a long-lived animal, where the accumulation of harmful substances must be avoided.

What should I look for in the labelling of complementary feed based on vegetable oils?

The main characteristics to be assessed on the label are:

  • Percentage of crude fats: a good oil will contain well over 90%.
  • The source of the oil: soya, flax, maize, rice or others.
  • L’additivazione di vitamina E che dovrebbe essere sempre presente.

Adding fat to your horse’s diet can be a great way to increase caloric intake and maintain condition in horses during the approaching winter season. However, before adding a fat source, assess with an equine nutrition expert the starting situation, based on the horse’s fat status and ration. Also take time to determine which fat source makes the most sense based on your horse’s overall diet and contact us for personalised advice for your stable or horse.


  • Effect of dietary fats with odd or even numbers of carbon atoms on metabolic response and muscle damage with exercise in Quarter Horse-type horses with type 1 polysaccharide storage myopathy. Lisa A Borgia, 2010
  • A comparison of grain, oil and beet pulp as energy sources for the exercised horse. K. G. Crandel, 1999
  • Effect of feeding thoroughbred horses a high unsaturated or saturated vegetable oil supplemented diet for 6 months following a 10 month fat acclimation. Harris PA, Pagan JD, 1999
  • Dietary fat affects heat production and other variables of equine performance, under hot and humid conditions. D S Kronfeld, 1996
  • High fat intake lowers hepatic fatty acid synthesis and raises fatty acid oxidation in aerobic muscle in Shetland ponies. S N Geelen, 2001
  • Short-term effects of a moderate fish oil or soybean oil supplementation on postprandial glucose and insulin responses in healthy horses. Ingrid Vervuert, 2010
  • Effects of substituting starch with fat on the acid-base and mineral status of female horses. A Zeyner, 2002
  • Lipid metabolism in equines fed a fat-rich diet. S N Geelen, 2000
  • https://thehorse.com/164293/will-an-omega-3-fat-supplement-help-my-horses-allergies/
  • https://thehorse.com/18459/feeding-fats-to-horses-not-just-a-diet-fad/