Manipulating gastrointestinal starch digestion to improve the efficiency of feed utilisation

Abstract

We have reviewed the ways in which the site of starch digestion in the gastrointestinal tract can affect the efficiency of feed utilisation in feedlot cattle. The benefits of starch digestion in the small intestine, as opposed to the rumen, include reduced risk of acidosis and higher energetic efficiency, provided that starch is digested in the small intestine. Undigested starch reaching the colon and caecum is less efficiently used and can lead to fermentative acidosis. There may be an opportunity to use appropriate grain selection and processing to reduce fermentation and ensure efficient digestion of starch in the small intestine. The potential for genetic variation between animals in starch digestion is also discussed. Efficient utilisation of feed grains is likely to involve appropriate choice and treatment of grain, as well as identification and selection of animals capable of efficient digestion of starch in the small intestine.