<![CDATA[Optimizing nutrient utilization from forage and residue combinations is crucial for advancing sustainable ruminant feeding systems. This study evaluated the dynamics of calcium (Ca) and phosphorus (P) in a mixture of Napier grass (Pennisetum purpureum) and banana peel (Musa acuminata × balbisiana) fermented by Trichoderma at various addition levels. A completely randomized design with four treatments was applied, and mineral concentrations were determined using standard laboratory procedures. Results showed a consistent increase in Ca content with higher banana peel additions, while P levels decreased, indicating a differential mineral response to fermentation. Relative changes showed an enrichment of Ca up to 24.05% and a decrease in P concentration, reflecting fermentation-mediated transformation of the substrate matrix. The Ca:P ratio increased from 1.39 to 1.96 across treatments, remaining within the acceptable nutritional range but approaching Ca-dominant conditions at higher addition levels. These findings indicate that microbial fermentation not only improves feed utilization but also re-establishes the mineral balance in the forage-residue system. Moderate inclusion levels provide a more balanced mineral profile, highlighting the importance of optimizing feed composition. Overall, integrating agro-industrial residues through fermentation offers a viable strategy to improve nutritional efficiency and support sustainable livestock production.]]>
