SMALL-INTESTINAL DIGESTION OF STARCH IN THE HORSE

In the present paper factors influencing small intestinal starch diges tibility in the horse are reviewed. The best method so far available i s small intestinal cannulation and the use of a marker. Post-mortem sp ot sampling may lead to considerable errors. Small intestinal starch d igestibility tends to decrease with increasing starch intake per meal. The small intestinal digestibility of oats and sorghum starch is usua lly high, while corn and especially barley starch are much less digest ible. Rough mechanical processing such as rolling or crushing does not significantly alter small intestinal starch digestibility of grains, while fine grinding of grain improves digestibility. Micronizing and e specially popping significantly increases starch digestibility in the small intestine of the horse. These effects can be explained by more o r less complete destruction of the botanical structure of the starch d uring processing. Feeding roughage with the concentrates leads to a de crease of starch digestibility in the small intestine. Addition of amy lase to ground corn increases digestibility. Individual factors of the horse, such as eating behaviour (chewing) and activity of amylase in the small intestine may also lead to considerable differences between horses on the same diet.