Understanding starch utilization in the small intestine of cattle

Ruminants possess the capacity to digest very large amounts of starch. However, in many cases diets approach 60% starch and even small inefficiencies present opportunities for energetic losses. Ruminal starch digestion is typically 75-80% of starch intake. On average, 35-60% of starch entering the small intestine is degraded. Of the fraction that escapes small-intestinal digestion, 35-50% is degraded in the large intestine. The low digestibility in the large intestine and the inability to reclaim microbial cells imposes a large toll on post-ruminal digestive efficiency. Therefore, digestibility in the small intestine must be optimized. The process of starch assimilation in the ruminant is complex and remains an avenue by which increases in production efficiency can be gained. A more thorough description of these processes is needed before we can accurately predict digestion occurring in the small intestine and formulate diets to optimize site of starch digestion.