Composition of Corn Silage Harvested in 2011

Dr. Maurice L. Eastridge, Extension Dairy Specialist, The Ohio State University

The weather conditions this crop year presented several challenges. It was a very wet spring and crops were planted quite late, resulting in a late harvest. Overall, the yields of forage appear to be quite good for this year's cropping season, but a considerable amount of variation occurred in time of planting and the precipitation during the growing season varied by month and area of the State (or even county). The first frosts in some areas and the intermittent rains during harvest presented several challenges in getting corn silage harvested that was planted late. Based on the data from the Dairy One Forage Laboratory in Ithaca, NY, the corn silage harvested this year have similar concentrations of NDF and starch as compared to the 2010 crop, but both 2010 and 2011 crops have higher starch and lower NDF concentrations compared to the 2009 crop (Table 1).  This likely reflects a higher ear to stalk ratio in the corn. At first glance, one would think that this means a higher energy value for the 2010 and 2011 corn silage. However because of the rapid dry down in some cases and the delayed harvest caused by rain, some farmers may have harvested the silage at higher DM than desired (harder kernels), and if a silage processor was not used, digestibility of the carbohydrates may be low. Digestibility should improve with advancing storage time. On the other hand, with proper stage of harvest and the higher starch (lower NDF) concentrations, rations need to be formulated with careful attention to physically effective fiber, particle size of the dry corn grain, and source of grain (dry versus high moisture versus steam flaked) that can affect ruminal pH and rate and extent of starch fermentation. Also due to the weather conditions, some bunkers were not filled and covered very quickly. In these situations, presence of molds and potential mycotoxins need to be assessed. The new crop corn silage should be analyzed, be allowed to stay in storage for at least several weeks if possible based on forage inventory, rations reformulated, and then observe cow performance (yield and composition of milk).

Table 1. Composition of corn silage harvested in 2009, 2010, and 2011.¹

¹CV = Coefficient of variation [(standard deviation/average)*100], DM = dry matter, CP = crude protein, ADF = acid detergent fiber, and NDF = neutral detergent fiber.