Animal feeds under ruminant production are a challenge, and ruminants are mostly fed on fibrous plants including high-moisture plant by-products (HMPBs). These HMPBs are available during the food processing periods and cannot be fed entirely in their fresh form. These resources are conserved in the form of silage for future feeding. Silage-making entails the anaerobic preservation of forages with the aid of additives that reduce the pH of the ensiled materials and preserve the forage. Most silage research work focuses mainly on the preservation of forages/plants, with less attention on HMPBs. This review focuses on the silage production from HMPBs (e.g., pulps/pomaces), challenges involved in the ensiling of these resources, use of additives (e.g., chemical additives), and growth performance of ruminants fed silage from these resources. This review will assist farmers from developing countries who rely on HMPBs as sources of animal feed.

The study evaluated the effects of replacing soybean meal (SBM) with marula oilcake (MOC) at equal inclusion (10% fresh weight) levels in whole-crop maize silage treated with or without lactic acid bacteria inoculants on fermentation characteristics, nutritive value, aerobic stability, and in vitro nutrient degradability. Maize was ensiled with SBM or MOC in a non-iso-nitrogenous 2 × 3 factorial design and either inoculated or uninoculated with Lalsil Fresh or Sil-All 4×4 for 90 days. Protein sources differed significantly (p < 0.05). The MOC showed high DM, EE, GE, and ADL, whereas SBM had high CP, ash, and IVOMD. Fibre fractions (aNDF and ADF) were similar (p > 0.05). The SBM control showed significantly high (p < 0.05) LA, NH₃-N, CP, IVOMD, propionic acid, and early gas production, indicating efficient fermentation. The SBM + Lalsil maintained low pH, and early OM, CP, and GE degradability. The SBM + Sil-All achieved the highest (p < 0.05) OM, NDF, and ADF degradability and acetic acid production than other treatments. The MOC control showed low (p < 0.05) pH, high fibre and GE, reduced butyric acid, and low 48 h gas production, indicating slower fermentation but improved stability. The MOC + Lalsil had high (p < 0.05) DM, low CO₂ and yeasts and moulds, and the highest (p < 0.05) CP degradability, propionic acid, and peak gas production at 12 h. The MOC + Sil-All showed high (p < 0.05) GE and WSC with peak GE degradation at 12 h, but low NDF degradability and reduced gas production. Overall, SBM improved degradability and fermentation efficiency, particularly with Sil-All, whereas MOC enhanced energy density and aerobic stability, with Lalsil optimising protein utilisation. Matching inoculant type to protein source is essential to optimise silage quality and rumen fermentation. Further research should assess different inoculant inclusion rates and include a maize-only control, and evaluate protein source inclusion under iso-nitrogenous conditions to allow more accurate comparisons.

Maize silage is widely used due to its high fermentability but requires protein supplementation, commonly from soybean meal (SBM). Rising costs have driven interest in alternative protein sources, while microbial inoculants are used to improve silage fermentation and stability. This study evalu-ated the effects of partially replacing SBM with marula oilcake (MOC), with or without bacterial inoculants, on maize silage fermentation characteristics, nutrient preservation, aerobic stability, and in vitro digestibility. Whole-crop maize (< 38% dry matter) was supplemented with SBM or MOC, treated with either Lalsil Fresh or Sil-All 4x4®, and ensiled anaerobically for 90 days. Post-ensiling analyses included chemical composition, fermentation end-products, microbial populations, aerobic stability, volatile fatty acid profiles, gas production, and in vitro digestibility. Fermentation quality, nutrient composition, and aerobic stability differed significantly among treatments (P < 0.05). SBM-based silages exhibited greater lactic acid production, higher crude protein and digestibility, but also elevated butyric and branched-chain volatile fatty acids, indicating increased proteolysis. In contrast, MOC-based silages showed lower lactic acid concentrations and digestibility but reduced butyric fermentation, suggesting improved protein preservation. Microbial inoculants enhanced fermentation parameters more effectively in SBM than in MOC silages. These results indicate that protein source and inoculation strategy markedly influence maize silage fermentation outcomes, highlighting the need for further processing of alternative protein supplements to optimize silage quality.

The aim of this study was to evaluate the growth performance, fermentation indices and meat quality of Sussex steers fed totally mixed rations that composed of graded inclusion levels of Napier grass (NP). Three experimental diets designated as diet 1 (0.0 g kg^–1 NP: Control), diet 2 (300 g kg^–1 NP grass) and diet 3 (600 g kg^–1 NP) were formulated. Twenty-four male steers aged 8 months with an average body weight of 185.0 ± 30 kg were used. In a completely randomized design, the animals were allocated to the diets and fed for 120 days. Dietary NP inclusion reduced (P < 0.05) the animals’ average daily gain and increased the feed efficiency. The steers’ daily feed intake and final body weight decreased (P < 0.05) with a 600 g kg^–1 inclusion level. The fermentation indices were not affected (P > 0.05) by the inclusion. While the inclusion reduced (P < 0.05) warm muscle temperature, it had no effect (P > 0.05) on carcass dressing percentage, warm and cold initial and ultimate pH. However, 600 g kg^–1 inclusion level reduced (P > 0.05) warm and cold carcass weights. Meat physical attributes, moisture characteristics and tenderness were not affected (P > 0.05) by dietary treatments, except for the 7-days aged meat thaw loss, which increased at 600 g kg^–1 inclusion level. Inclusion of 300 g kg^–1 increased meat protein and fat, but dry and organic matter contents decreased with increasing inclusion levels. Dietary inclusion of NP grass up to 300 g kg^–1 in steers’ diets improved feed intake, carcass traits and yielded meat high in protein and fat.