Using by-products added to grass silage in the total mixed ration (TMR) silage form can bring advantages to the ensiling process, raising DM levels, absorbing moisture, and improving the silage’s chemical composition. The aim of this study was to evaluate the effect of babassu by-products’ inclusion substitution for corn in Guinea grass silage in the total mixed ration as an alternative feed for ruminants. The experiment was a completely randomized design with four treatments (silage) and five replications (silo). There was a significant difference in the fermentation profile and losses of silage (p < 0.001), some organic acids (lactic and butyric acids, p < 0.001), and the percentage of lactic acid in fermentation products (LA:FP, p < 0.001). The TGS showed the highest average for the variable’s maximum temperature (p < 0.001) and hours/max temperature (p = 0.011). Babassu by-products could eventually replace 50% of corn in total mixed rations silage containing Guinea grass, meeting the suggestion for the total mixed ration silage.