Too little fat
The most common rations for horses contain little fat. Amongst forages such as hay and haylage, the fat content is usually 10-15 grams of digestible fat per kg of dry material. In barley the content of fat is approximately 20 grams and in oats 50 grams per kg.
Fat in the form of vegetable oils can be an important energy supplement for the horse, particularly for horses that have problems with the regulation of their blood sugar (glucose) levels, and whose ration therefore should be one with minimal amounts of cereals. Fat is therefore recommended for horses that have a history of laminitis or have problems with "tying up" symptoms and muscle degeneration.
Too much fat
The horse digests fat well, when consumed in moderate quantities. If we give vegetable oil in the ration, we expect that it is unproblematic to give up to 0.10 kg per 100 kg of body weight. This means that we could give 0.5 litres per day to a horse of 500 kg. The oil should be divided into at least two meals. The horse is not particularly fond of vegetable oil. You will therefore have to mix the oil with feeds that the horse will eat readily, such as grain or concentrates.
Fat is rich in energy, and usually contains around three times as much energy as conventional feed mixtures. This means that 0.3 kg of oil has about the same energy value as 1 kg of concentrates.