Horse & Hound
Simple science: sugar and starch
CARBOHYDRATES are one of the three main classes of foods, along with proteins and fats, and provide a horse’s primary source of energy.
Carbohydrates may form part of the structure of grass (termed structural carbohydrates), or are stored by the grass as sugar or starch. These non-structural carbohydrates can be digested easily and absorbed rapidly. Glucose, fructose and galactose are the simplest sugars and the building blocks for other carbohydrates. Starches are chains of simple sugars that are broken up easily and also readily digested.
Most sugars and starches are absorbed in the small intestine. Food and water move through the small intestine in around 45 minutes; any excess sugars and starches, along with structural carbohydrates and proteins, pass through it to reach the large intestine.
Structural carbohydrates, commonly termed “fibre”, are fermented in the large intestine by bacteria. The resultant volatile fatty acids produced can be absorbed by the horse and also provide him with energy. Sugars absorbed from the small intestine should provide a relatively small proportion of the horse’s energy requirements; far more should come from the fermentation of fibre in the large intestine.