Dry matter concentration and corn silage density: Effects on forage quality

Considering the hypothesis that density and dry matter (DM) concentration may be used as indicators of silage nutritional quality, the aim of the present study was to determine density and maturation stage (i.e. DM concentration) of corn silages under farm conditions in Brazil, establishing relationships between density and physical and chemical characteristics. In a completely randomized design, 20 bunkers of corn silage, each from a different farm, were used for data collection. Using a coring machine, 5 samples of silage were extracted from an exposed face of each silo and samples were analyzed for density of compaction, plus concentrations of DM, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), total digestible nutrients (TDN), total carbohydrate (TC), non-fiber carbohydrate (NFC) and starch (STA), as well as electrical conductivity. There was significant variation in many of the parameters measured with the greatest variation in density on a natural matter basis. Negative correlations were observed between percentages of DM, NDF and ADF in the silage and silage density on a natural matter basis (P<0.05). On the other hand, DM% was positively correlated with concentrations of STA, TDN and TC (P<0.05). Density on a DM basis showed positive correlation with STA but was negatively correlated with NDF and ADF (P<0.05) indicating that the more fibrous material is harder to compact. A technology transfer program seems warranted to inform Brazilian farmers of these findings and the importance of harvesting forage at a stage of growth when quality would be better to increase the probability of achieving adequate compaction of the ensiled material and hence better quality of material at feeding out.