Effects of packing density and homofermentative microbial inoculant on the physical quality, chemical composition, and estimated nutritive value of maize silage

This study evaluated the effects of packing density (500, 650, and 800 g/L fresh weight) and a homofermentative microbial inoculant (containing Lactobacillus plantarum and Enterococcus faecium; 0 or 500 mg/kg) on the physical quality, chemical composition, and estimated nutritive value of maize (Zea mays L.) silage. A completely randomised design with a 3 × 2 factorial arrangement was used, with each of the six treatment combinations replicated four times (n = 24). Forage harvested at the ½ milk line stage was ensiled in 2-L glass jar silos and stored for 42 days. Packing density had no significant effect on silage pH, physical quality scores (colour, odour, structure), or any chemical or nutritive value parameter (P > 0.05). However, inoculant application significantly reduced organic matter, starch, and non-structural carbohydrate concentrations, while increasing ash, neutral detergent fibre, and hemicellulose contents (P < 0.05). Lower estimated dry matter intake, relative feed value, and metabolizable energy values were observed in inoculant-treated silage (P < 0.05), whereas digestible dry matter, total digestible nutrients, and net energy for lactation were unaffected. Significant interactions between packing density and inoculant application were observed for organic matter and ash, with the greatest differences occurring at the lowest packing density (500 g/L). These findings indicate that, the fermentation and nutritive characteristics of maize silage were governed primarily by inoculant application rather than packing density and suggest that homofermentative inoculants should be applied with consideration of substrate characteristics rather than as a routine practice.