Use of post-harvest sugarcane residues as complete feed silage for sheep: effects on nutritional value, fermentation characteristics, and digestibility.

This study was conducted to evaluate the potential of incorporating post-harvest sugarcane residue (PHSR), consisting of tops and lateral leaves, as a partial replacement for corn forage (CF) in complete feed silage (CFS) technology for ruminants, using both in vitro and in vivo assessments. The experimental design involved four CFS treatments: a control diet containing 700 g/kg dry matter (DM) of CF and three treatments in which CF was replaced with PHSR at 100, 200, and 300 g/kg DM levels. After 60 days of ensiling, silages were evaluated for fermentation characteristics, chemical composition, and in vitro gas production (GP). Subsequently, the silages were fed to 20 Lori-Bakhtiari ewes (3–4 years old; average body weight: 47.2 ± 1.12 kg) in a completely randomized design with five replicates per treatment. The chemical composition of the silages revealed that increasing PHSR inclusion in CFS resulted in a linear (L) increase in DM and fiber fractions including neutral detergent fiber (NDF), acid detergent fiber (ADF), and lignin (L, P < 0.01), while organic matter (OM), ether extract (EE), and non-fiber carbohydrates declined (L, P < 0.01). In vitro GP at earlier time points and up to 72 h showed no significant differences (P > 0.05), but GP at 96 and 120 h, as well as the GP potential (b), decreased linearly (L, P = 0.01) with increasing PHSR in CFS. In vivo findings indicated no significant effect of CFS treatment on the intake of DM, OM, CP, and NDF (P > 0.05), although ADF intake increased (L, P < 0.01) and EE intake decreased (P < 0.01) with higher PHSR levels. Apparent digestibility of most nutrients was unaffected, except for a linear decline in ADF digestibility (L, P < 0.05). From rumen fermentation profiles, pH and volatile fatty acid concentrations remained stable across treatments. However, ruminal ammonia-N and blood urea nitrogen concentrations increased linearly (L, P < 0.05). The results demonstrate that PHSR can be effectively used as a partial replacement for CF in CFS innovation up to 300 g/kg DM without negatively affecting intake, digestibility, or rumen fermentation. Although some shifts in nitrogen metabolism were observed, overall silage quality, feed intake and digestibility remained acceptable.