Energy Carbohydrates are the main source of energy for the horse. Carbohydrates include the simple sugars, starches, and fibre. Sugar and starch are easily digested and absorbed while fibre is a more complex form of carbohydrate that is largely indigestible. Micro-organisms inhabiting the large intestine of the horse, however, break down fibre into simpler compounds that the horse then uses as an important source of energy. Fibre that is not broken down by the micro-organisms, passes through the horse undigested, adding bulk to the manure and maintaining regular bowel movements.
Grains are high in easily digestible carbohydrates, while hay and pasture are high in fibre.
Energy requirements for horses vary greatly depending on the activity level, whether the animal is growing, lactating or pregnant, and the harshness of the climate. It is very important that the correct amount of energy is supplied. Overfeeding will result in an obese pony with adverse effects on the health and performance of the animal. An overweight pony is prone to founder, colic, joint problems, and foaling problems in the mare. Likewise, failure to meet energy requirements will result in loss of body condition.