This study was evaluated the effects of different carbohydrate sources on the fermentation profiles, chemical compositions, and correlation of fermentation profiles and chemical compositions with water-soluble carbohydrate (WSC) of alfalfa (Medicago sativa) silage. Alfalfa was harvested at early flowering stage from the third cutting in September 2018, wilted to 32% dry matter (DM) and chopped into 1–2 cm pieces. Treatments included the addition of pectin (PEC), starch (STA; powdered corn), molasses (MOL), and fructose (FRU), as well as distilled water as a control (CON). Afterward, 300 g of prepared alfalfa was packed into polyethylene bags, vacuumed, and sealed, after which they were stored at room temperature for 1, 3, 7, 15, and 30 d. FRU and PEC additions resulted in desirable fermentation profiles and chemical compositions throughout the ensiling period. FRU and PEC rapidly decreased the pH and increased Fleig’s point, exhibiting lower pH and higher Fleig’s point from 3 d to the end of ensiling. Acetic acid (AA), propionic acid (PA) and ammonia nitrogen (AN) contents of FRU and PEC were lower at 30 d after ensiling. Higher lactic acid (LA) contents were found in FRU and PEC from 7 d to the end of ensiling and higher LA:AA ratios from 15 d to the end of ensiling. Butyric acid (BA) was not detected at any point during the ensiling period. Additives exhibited higher DM content from 7 to 30 d after ensiling. The WSC content decreased as the number of ensiling days increased and was stable from 15 d to the end of ensiling. PEC, STA, and FRU exhibited higher WSC than CON. FRU and PEC improved the fermentation quality throughout the ensiling period. Thus, FRU and PEC or related agricultural byproducts may offer alternative additives for improving the alfalfa silage fermentation profile.

The influence of mixing alfalfa with whole-plant corn in different proportions on the fermentation characteristics and bacterial community of silage was investigated. Alfalfa and whole-plant corn, harvested at dry matter content of 276.47 and 328.43 g/kg fresh weight, accordingly, were chopped to approximately 2 cm and mixed at ratios of 100:0 (C0, control), 80:20 (C20), 60:40 (C40), 40:60 (C60), 20:80 (C80) and 0:100 (C100) on a fresh weight basis, respectively. Silos of each treatment were produced in triplicate and anaerobically fermented in darkness for 100 days at room temperature (20–21 °C). At silo opening, silage fermentation characteristics and bacterial composition and diversity were analyzed. The C0 silage was weakly preserved, evidenced by a low lactic acid concentration and a high value of pH, acetic acid, propionic acid, butyric acid and ammonia nitrogen. With corn proportion in the mixture increasing from 0% to 40%, silage pH, acetic acid, butyric acid and ammonia nitrogen level decreased, whereas the value of lactic acid and lactic acid to acetic acid ratio increased. The C40, C60, C80 and C100 silages’ Flieg score, used to evaluate the overall fermentation quality, was above 80 and higher than C0 (25) and C20 (61) silages. The C0 silage contained a complex bacterial community at the genus level, consisting mainly of Enterococcus (38.86%), Enterobacteria (20.61%), Rhizobium (8.45%), Lactobacillus (8.15%), Methylobacterium (5.54%) and Weissella (5.24%). As corn percentage increased from 0% to 40%, the relative abundance of desirable Lactobacillus increased and undesirable Rhizobium and Methylobacterium population reduced. With corn proportion in the mixture increasing from 0% to 40%, inclusion of corn to alfalfa at ensiling significantly improved silage fermentation quality and shifted the bacterial community for better silage preservation. Overall, high quality silage was produced when alfalfa was combined with at least 40% whole-plant corn on a fresh weight basis.

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.

Information regarding the vitamin content of silage is limited. This study investigated the changes in the vitamin content of alfalfa and Chinese leymus silages with or without a lactic acid bacterial inoculant. Alfalfa at the early flowering stage and Chinese leymus at the full-bloom stage were harvested. The treatments for each forage type were control (deionized water only) and 1×106 colony-forming units (cfu) Lactobacillus plantarum (LP) g-1 FM. After 45 d ensiling, all silages were sampled for evaluating the vitamin content, fermentation quality and chemical composition. The LP inoculant decreased the pH and ammonia nitrogen content of the alfalfa and Chinese leymus silages and significantly (p < 0.05) increased the lactic acid, acetic acid, propionic acid content and Flieg`s points. Prior to ensiling, the levels of five B-group vitamins (thiamin, riboflavin, niacin, pantothenic acid, pyridoxine) and α-tocopherol in alfalfa were significantly higher than those in Chinese leymus (p < 0.01). Ensiling decreased the levels of the five B-group vitamins in both alfalfa and Chinese leymus while increasing the α-tocopherol content of Chinese leymus. The thiamin, riboflavin, niacin and pantothenic acid levels in the LP-treated silage were significantly (p < 0.05) lower than those in the untreated silage for both forages. The α-tocopherol content in the LP-treated alfalfa silage was significantly (p < 0.05) higher than that in the untreated alfalfa silage. There was no significant (p > 0.05) difference in pyridoxine content between the untreated and LP-treated silages for both forages. With or without LP inoculation, the levels of the five B-group vitamins (thiamin, riboflavin, niacin, pantothenic acid, pyridoxine) in alfalfa and Chinese leymus decreased after 45 days of ensiling, while the α-tocopherol content of Chinese leymus increased. The LP inoculant improved the fermentation quality of both the alfalfa and Chinese leymus silages but increased the thiamin, riboflavin, niacin and pantothenic acid loss in the two forages after fermentation.

Alfalfa (Medicago sativa) is one of the high protein ingredients of fermented total mixed ration (FTMR). Additionally, FTMR is widely used to satisfy the nutrition requirements of animals. This study was conducted to confirm the fermentation characteristics, chemical compositions and protein fractions changes when replacing ensiled-alfalfa with fresh-alfalfa in FTMR with additives. Three additives were separately applied to fresh-alfalfa total mixed ration (TMR) and ensiled-alfalfa TMR, including molasses (MOL), Lactobacillus plantarum (LP) and MOL plus LP (MOL+LP). The same volume of distilled water was sprayed onto the prepared TMR as performed for the control (CK). Each treatment included 18 repetitions and opened 3 repetitions at each fermenting day (1, 3, 7, 15, 30 and 60 d). The results showed that fresh-alfalfa FTMR (F-FTMR) exhibited slight changes in the fermentation characteristics during the first 7 d and showed similar trends in terms of the pH and organic acids content to ensiled-alfalfa FTMR (E-FTMR). The lactic acid contents of F-FTMR were significantly lower than those of E-FTMR at 60 d fermentation and the ammonia nitrogen contents were lower than E-FTMR during the entire fermenting period. The crude protein of the F-FTMR was enhanced after 60 d of fermenting. F-FTMR supplemented with MOL+LP exhibited a lower nonprotein nitrogen content, variable to slow protein and indigestible protein contents, and higher fast degradable protein and true protein degraded intermediately contents at 60 d fermenting, indicating that it effectively inhibited protein degradation.

The objective of this experiment was to evaluate the effects of the chopping length and additive on the fermentation characteristics and aerobic stability in silage of Leymus chinensis. L. chinensis was chopped to 1–2 cm and 4–5 cm, and immediately ensiled with the three treatments, i.e., 2% sucrose (fresh weight basis; SU), 1 × 10⁵ cfu/g Lactobacillus plantarum (LP) or 1 × 10⁵ cfu/g LP plus 2% sucrose (SU+LP). Silage treated with distilled water served as the control. After silage processing for 30 and 90 d, the fermentation quality of L. chinensis silage was evaluated. The composition of the fermentation products and the pH value in the silage were determined at 1, 3, 5 and 7 d after opening the silo. The results showed that in L. chinensis silage there was a lower pH value, higher lactic acid content and better aerobic stability at the 1–2 cm length than those at the 4–5 cm (p < 0.001). When the chopping length was 4–5 cm, the addition of either LP or SU+LP increased the content of lactic acid and acetic acid, and decreased the pH value and butyric acid content, compared to those of the control and SU treatment (p < 0.001). Furthermore, combination treatment of SU+LP performed better than LP alone, and the aerobic stability time of L. chinensis silage at 4–5 cm without any additives was the worst. In conclusion, enhanced fermentation quality and aerobic stability can be obtained by processing L. chinensis silage with the shorter length. When the L. chinensis is cut longer, e.g., 4–5 cm in this study, LP or SU+LP could be used as an effective method to improve the fermentation quality and aerobic stability of L. chinensis silage.