Elephant grass silages have high moisture content, causing nutrient loss, mainly by effluent production. The use of moisture absorbent additives, such as patauá, Oenocarpus bataua meal, can be a strategy to reduce losses in these silages. The aim of this study was to determine the fermentation losses, microbiological composition, fermentative characteristics, and chemical composition of elephant grass silage with increasing levels of inclusion of patauá meal. The experiment was conducted in a completely randomized design, with four concentrations of patauá meal (7%, 14%, 21%, and 28%, based on fresh matter) and a control without patauá, and five replicates. The elephant grass was collected manually after 60 days of growth. After chopping, the grass was homogenized, mixed with the patauá meal according to the established treatments, and ensiled in experimental silos of 15 L. The inclusion of patauá meal in elephant grass silage had positive effects on the chemical composition and effluent loss. It significantly increased dry matter, organic matter, crude protein, nitrogen insoluble in neutral detergent and acid, ethereal extract, lignin, and non-fibrous carbohydrates of the silages. It also reduced effluent losses, neutral and acid detergent fiber contents, and cellulose. Our findings contribute towards reducing the environmental impact caused by the production of effluents during ensilage of tropical grasses and providing a potential use for the residue from the production of patauá oil, thus avoiding disposal in the environment. (AU)