No abstract

Alfalfa sometimes cannot be harvested in time due to the rainy season. To improve the fermentation quality, protein quality and digestibility of alfalfa silage harvested late, Lactobacillus plantarum (LP) and molasses were applied in an actual production process in this study. Alfalfa harvested at the full bloom stage was ensiled with (1) distilled water (control), (2) 1 × 106 colony-forming units LP/g fresh matter, (3) 15 g molasses/kg fresh matter (M) or (4) LP + M (LPM) for 55 days. Alfalfa ensiled with LP and/or molasses showed significantly lower pH and ammonia nitrogen contents than the control silage (p < 0.05). All additive treatments decreased nonprotein nitrogen contents and preserved more true protein (p < 0.05). However, molasses increased the acid detergent insoluble nitrogen content in the protein fractions (p < 0.05). The LP significantly improved the maximal cumulative gas production and the maximum gas production rate (p < 0.05) in the in vitro trial. Finally, both LP and molasses improved the neutral detergent fiber digestibility of the alfalfa silage (p < 0.05). The LP and molasses improved fermentation quality and digestibility and preserved more true protein in baled alfalfa silage harvested late in an actual production process. The LP utilized the excessive molasses and partially ameliorated its negative effects of causing higher acid detergent insoluble nitrogen content.

This study aimed to evaluate the effect of the application of an inoculant and a preservative on the fermentation quality, in vitro digestibility, and aerobic stability of alfalfa silage-based fermented total mixed ration (TMR). The TMR was ensiled with (1) no additives (control), (2) Lactobacillus plantarum (LP), or (3) potassium sorbate (PS). The V-scores of all silages were higher than 80 points during the 30 days of ensiling. The addition of LP and PS had no effects on the in vitro parameters, such as in vitro digestibility and in vitro gas production (p > 0.05). LP-treated silage showed similar fermentation quality and comparable aerobic stability to the control (110 h). The LP only decreased the ammonia nitrogen (NH3-N) content (p < 0.05) during ensiling. The PS significantly increased the pH of TMR silages (p < 0.05). Meanwhile, the addition of PS improved the aerobic stability (>162 h) of TMR silage, indicated by the higher water-soluble carbohydrate content and lower NH3-N content in comparison with those in the control after aerobic exposure (p < 0.05). The improvement in fermentation quality is extremely small in terms of applying LP in TMR silage based on a large percentage of other silage ingredients. The PS is effective in conserving unpacked TMR silage and showed the potential to reduce the risk of ruminal acidosis in livestock.

This study aimed to evaluate the effects of different proportions of alfalfa silage on the fermentation quality, in vitro digestibility, and aerobic stability of total mixed ration (TMR) silage. Three TMRs were prepared with different silage contents on a fresh matter basis: (1) 60% alfalfa silage (AS60), (2) 40% alfalfa silage (AS40), and (3) 20% alfalfa silage (AS20). The lactic acid in AS60 did not increase after 30 days of ensiling (p > 0.05). Butyric acid was detected in the AS20 group after 14 days of ensiling. The AS60 group showed significantly higher in vitro dry matter digestibility than the AS20 group (p < 0.05). The aerobic stability of TMR silage gradually increased with a decreasing percentage of alfalfa silage (p < 0.05). Unlike AS60, which directly gained an acidic environment from the alfalfa silage, AS40 developed a stable acidic environment during ensiling and further improved aerobic stability. However, when the percentage of alfalfa silage was reduced to 20%, a risk of clostridial spoilage occurred in the TMR silage. Therefore, the addition of 40% alfalfa silage to TMR is optimal and could achieve both good fermentation quality and considerable resistance to aerobic deterioration in TMR silage.

The present study aims to estimate the dynamic effects of moisture levels and inoculants on the fermentation quality and in vitro degradability of Stylosanthes silage. In this experiment, Stylosanthes was ensiled with (1) no additive (control), (2) Lactobacillus plantarum (LP), (3) Lactobacillus plantarum carrying heterologous genes encoding multifunctional glycoside hydrolases (xg), or (4) LP + xg and was wilted until different moisture levels (60% and 72%) were attained. The ensiled bags were unpacked after different storage periods to determine the chemical composition and fermentation quality of the Stylosanthes silage. Moreover, the in vitro degradability was also determined 45 days after the ensiling process. The results show that the silage prepared with freshly mowed Stylosanthes also had a lower pH and NH3- N content. Adding transgenic engineered lactic acid bacteria xg not only decreased the NDF and ADF content of the silage, but also improved the in vitro digestibility significantly. We concluded that the addition of xg to Stylosanthes silage can improve its quality and increase in vitro digestibility and gas production. The results provide technical support and a theoretical basis for the utilization of warm-season forage silage.