Fiber Digestibility and Starch Content of Corn Silage

Corn silage is a major forage crop in Idaho, supporting its dairy industry. Corn silage produces more digestible energy per acre than other forages. Nutritionally, corn silage is palatable when ensiled properly, and high in energy because it typically contains 50% corn grain. Digestibility of starch declines as the kernel matures. Effective roller processing of corn silage ensures that most of the energy in corn kernels is readily digested by dairy cows. Fiber digestibility can be measured as in vitro Neutral Detergent Fiber digestibility (NDFD) using different fermentation times (24, 30 or 48hour). The bm3 gene in corn plants reduces lignin content, increases NDFD in vitro, but may not increase NDFD in vivo. Brown midrib corn silage resulted in additional milk per cow per day from increased dry matter intake, but not improved digestibility. Corn silage production is most profitable when yield and dry matter digestibility are highest. High yield with low fiber digestibility, low starch availability, or ineffective fiber can result in nutritional problems for high producing dairy cattle.