# Ensiling Time and Mixed Microbe Fermented Liquid Modulate In Vitro Digestibility and Rumen Fermentation of Fermented Total Mixed Rations

## TL;DR

This study shows that fermenting animal feed with a specific mix of microbes for 14 days improves digestion and reduces methane emissions in ruminants.

## Contribution

The study identifies optimal conditions for using mixed microbes to enhance feed quality and fermentation efficiency in ruminant systems.

## Key findings

- A 14-day fermentation with 0.5% MMFL increased crude protein and reduced fiber in feed.
- This treatment improved digestibility and boosted volatile fatty acids while lowering methane output.
- Microbial communities shifted toward higher bacteria and fungi, and fewer protozoa.

## Abstract

Fermented total mixed rations (FTMR) can enhance feed stability and utilization, but their performance varies with ensiling duration and microbial enrichment. This study evaluated FTMR treated with mixed microbes fermented liquid (MMFL) using in vitro gas production assays. A 14-day fermentation combined with 0.5% MMFL improved nutrient profiles, increased digestibility, and boosted volatile fatty acid formation while lowering fiber content and estimated methane output. Microbial communities shifted toward higher bacterial and fungal populations and fewer protozoa. These results indicate that MMFL is a promising additive for producing higher-quality FTMR and supporting more efficient, sustainable ruminant systems.

This study investigated how varying the ensiling period and the level of mixed microbes fermented liquid (MMFL) influences the chemical composition, in vitro degradability, rumen fermentation profile, and microbial ecology of fermented total mixed rations (FTMR). A completely randomized 4 × 4 factorial design was used, incorporating four fermentation durations (0, 7, 14, and 21 days) and four MMFL inclusion rates (0, 0.5, 1.0, and 1.5% of DM). Both factors exerted significant effects on FTMR quality (p < 0.05). The combination of a 14-day fermentation period with 0.5% MMFL consistently produced the most desirable outcomes. Under these conditions, crude protein concentration rose from 12.0% to 14.3% of DM, while neutral-detergent fiber declined from 54.2% to 49.1%. Improvements were also observed in in vitro digestibility, with DM and OM increasing by 9–12% relative to the untreated control (p < 0.05). Fermentation end-products were enhanced, as total volatile fatty acids increased by 15% (92.4 vs. 80.1 mmol/L), and the molar proportion of propionate increased from 24.5 to 29.2 mol/100 mol, thereby lowering the acetate-to-propionate ratio (2.4 vs. 3.0; p < 0.05). Estimated methane production declined by 18% (p < 0.01). Microbial counts reflected a shift toward a more efficient fermentative community, with bacterial and fungal populations increasing by 21% and 18%, and protozoa decreasing by 25% (p < 0.05). Overall, moderate MMFL supplementation during a 14-day ensiling phase enhanced nutrient conservation and fermentation efficiency, suggesting practical value for improving FTMR utilization in ruminant systems. Further in vivo and economic evaluations remain necessary.