Effect of olive cake on the fermentation quality of corn stalk silage

This study was conducted to investigate the effect of olive cake on the fermentation quality of corn stalk silage. Five treatments were prepared: corn stalk (C), 5% olive cake + 95% corn stalk (T₅), 10% olive cake + 90% corn stalk (T₁₀), 20% olive cake + 80% corn stalk (T₂₀), and 30% olive cake + 70% corn stalk (T₃₀), with four replicates per treatment at 300 g per replicate. After being stored at room temperature and the dark for 45 days, the fermentation indicators and nutritional components of the silage were measured. The results showed that the sensory score of C, T₅, and T₁₀ was excellent, while T₂₀ and T₃₀ were good. In terms of fermentation quality, the pH of T₃₀ was significantly higher than those of the other treatments (P < 0.05), while the pH values of T₁₀ and T₂₀ were significantly higher than those of C and T₅ (P < 0.05). The lactic acid content of T₅, T₁₀, T₂₀, and T₃₀ was significantly lower than that of C (P < 0.05). The lactic acid:acetic acid ratio of C and T₅ was significantly higher than that of T₁₀, T₂₀, and T₃₀ (P < 0.05); whereas the lactic acid ꞉ acetic acid ratio of T₁₀ and T₂₀ was significantly higher than that of T₃₀ (P < 0.05). However, there were different trends in the ammonia nitrogen ꞉ total nitrogen ratio for which T₂₀ and T₃₀ was significantly lower than that of C (P < 0.05). The contents of dry matter, neutral detergent fiber and acid detergent fiber in mixed silage increased significantly with the increase of olive cake (P < 0.05). However, the water soluble carbohydrate content decreased significantly (P < 0.05). After comprehensive analysis of sensory scores, fermentation indicators, and nutritional value, the maximum addition ratio of olive cake is 20%. The mixed silage of olive cake and corn stalk provides a strategy for the feed utilization of olive cake.