A starch-heavy diet predisposes the horse to blood sugar fluctuations
A horse’s nutritional needs vary widely depending on workload and the individual horse’s absorption of nutrients. However, a horse’s performance level can be influenced to some extent through feeding. During a lighter training period, the horse should also be fed more lightly, so that when the energy allowance is increased during harder training, the additional energy produces a clear effect on performance.
Healthy, functional musculature and normal muscle function are the cornerstone of performance. During heavy exertion, however, muscle-related problems can also occur. Sweating and defecation during intense performance or competition remove fluid from the horse’s body. Fluctuations in fluid balance can cause issues, because dehydration thickens the blood and weakens blood flow in the vessels. As a result, part of the musculature is left without the substances needed for effective muscle work—substances that help muscles cope and recover, including from the effects of lactic acid. With fluid loss, the removal of metabolic waste products from the body also becomes less effective.
Adequate fibre intake is important for maintaining the horse’s fluid balance. Fibre in the large intestine binds water for the body’s needs. For example, the fibres in hay are well suited to supporting a horse’s fluid balance during heavy work.
Blood sugar swings reduce performance
One of the most common reasons for muscle disturbances is overfeeding. A diet high in starch may impair muscle function. A concentrate-based diet—where the feed consists largely of ingredients high in sugar and starch—binds substantial amounts of water in the large intestine. However, this water does not get absorbed into the body. Instead, it weakens fluid balance.
The starch in concentrates raises the horse’s blood sugar. As long as blood sugar remains elevated, performance is good. When the performance ceiling is reached, blood sugar levels begin to drop. At that point the horse starts using its sugar reserves and performance declines. When blood sugar values return to a normal level, performance also returns relatively quickly.
Pushing a horse to the upper limit of its performance should be considered carefully, because in these situations blood sugar drops and the horse has to rely on its sugar reserves. A horse that is fed concentrates 3–5 hours before exertion ends up in the “risk zone.” A surprisingly poor competition performance may in fact be explained by an unsuitable interval between feeding and competition for that particular horse.
Fats, on the other hand, are a relatively easy energy source for the body. When they are burned, they produce less metabolic waste than carbohydrates. When microorganisms in the large intestine break down plant fibres, energy-yielding fatty acids are produced. Fatty acids obtained directly from feed are stored in the body as fat and, in their own way, help protect the body from harmful waste products. For this reason, the diet of competition horses and horses in hard work should contain a moderate amount of fats and a fairly high amount of fibre.
In feeding, it is advisable to use ingredients that do not raise blood sugar unnecessarily high, because the counter-reaction is always an equally steep drop. Preparing for a competition, for example, is best started with fibre-rich nutrition already a few days before the event, so that the horse’s energy “loading” begins via the absorption processes of the large intestine. A supplement that is high in fat and contains amino acids increases the body’s energy reserves and reduces the formation of waste products in the musculature.
