September 2012 - Fat in the horse's ration
The horse’s natural diet consists of leaves, stems and seeds of grasses and other plant material. In essence, such plant material consists of carbohydrates. Since most of the plants and plant ingredients are low in fat content, most diets we plan for horses will contain little fat. In forages, such as hay and haylage, there is usually 10-15 grams of digestible fat (lipids) per kg dry feed. In barley and wheat, the fat content is about 20 grams per kg, while oats are more fatty and contain about 50 grams per kg. There are also special kinds of oat available with a fat content of 90 to 100 g per kg.
Fat is rich in energy, and fat in the form of vegetable oils such as soybean oil and corn oil, can provide an important energy supplement in the ration. Vegetable oil contains around three times as much energy as the usual cereals and animal feed mixtures. This means that 0.3 kg of oil has approximately the same energy value as 1 kg feed.
Fats are digested in the small intestine of all animals. The fat is emulsified by means of substances in bile, cleaved by the enzymes from the pancreas, and subsequently transported through the intestinal wall into the bloodstream. Horses can digest vegetable oils well when given in moderate amounts, i.e. up to 1.0 decilitres (0.1 kg) per 100 kg body weight. Thus, a horse of 500 kg body weight can get up to 0.5 litres per day. However, most horses are not particularly fond of vegetable oils, so it is more common to give 0.3 to 0.5 dl per day. The oil should be given spread over at least two meals and mixed with other feed that the horse will eat readily.
Some horses have trouble regulating their blood sugar (insulin resistance), or experience recurrent muscle problems (muscle paralysis, tying up). These disorders are probably linked to a rapid absorption of glucose following meals with grain and concentrates. Such meals will give periods with elevated levels of glucose in the blood (“high blood sugar”). For such horses, diets with a low content of starch and sugar are recommended. Oats, barley and corn are high in starch (500-600 g per kg). This starch is absorbed after cleavage into glucose in the intestine. It is therefore important to reduce the amount of starch-rich concentrate in rations to horses with the mentioned disorders. To achieve this, fat comes in as a useful alternative source of energy. Fat is absorbed as fatty acids which have little impact on the horse's blood glucose concentration, and can therefore be fed as a replacement for parts of the concentrate in the ration.
Vegetable oil contains predominantly fat (triglycerides) and few other nutrients. It is therefore important to make sure that the ration provides balanced amounts of all the other nutrients needed by the horse. This is where the PC-Horse program will help. You can quickly check that the ration gives a balanced supply of nutrients, and correct any shortages or surpluses. You will also get information about how much fat the ration contains, and whether this is within the recommended range.