This study evaluated the effects of different combinations of added lactic acid bacteria and cellulase applied at two growth stages on chemical composition and in vitro rumen digestibility of Leymus chinensis silage. Fresh grass was harvested at early heading stage (S1) and late heading stage (S2), respectively, and ensiled with five additives: 200 U cellulase (C) kg−1 fresh matter (FM), 1 × 105 colony‐forming units (cfu) Lactobacillus plantarum (LP) g−1 FM, 1 × 105 cfu Lb. casei (LC) g−1 FM, LP+C, LC+C and a control (CK). Four replicates of each treatment were weighed into 5‐L plastic buckets, and the mini silos were stored at ambient temperature (~30°C) for 60 d. Leymus chinensis harvested at S2 showed relatively higher neutral detergent fibre content, coliform bacteria count and lower crude protein content than S1. All additives decreased the pH and ammonia nitrogen (NH3‐N) content of L. chinensis silage (P < 0·001) except C. LP+C and LC+C decreased fibre content and increased water‐soluble carbohydrate content (P < 0·001). The silages were further anaerobically incubated in vitro at 39°C for 48 h with buffered rumen fluids of lactating cows. Leymus chinensis harvested at S2 showed lower in vitro dry‐matter disappearance, NH3‐N, total volatile fatty acid (VFA) content and higher average gas production rate (P < 0·05) than S1. In conclusion, Leymus chinensis should not be harvested too late. Compared with other treatments, a combination of Lb. casei (LC) with cellulase resulted in better fermented silage, but further testing is needed to confirm its efficacy.

This study investigated the effects of different additives on fermentation quality and aerobic stability of Leymus chinensis silage. Treatments included (i) no additive, (ii) 3 mL kg−1 formic acid (FA), (iii) 6 mL kg−1 FA, (iv) 5 mL kg−1 acetic acid (AA), (v) 10 mL kg−1 AA, (vi) 2 mL kg−1 propionic acid (PA), (vii) 4 mL kg−1 PA, (viii) 5 mL kg−1 butyric acid (BA), (ix) 10 mL kg−1 BA, (x) 1.0 g kg−1 potassium sorbate (PS), (xi) 1.0 g kg−1 sodium benzoate (SB), (xii) 1 × 108 colony‐forming units (cfu) kg−1 Lactobacillus (Lb) plantarum LP (LP), (xiii) 1 × 108 cfu kg−1 Lb. brevis LB (LB) and (xiv) 1 × 108 cfu kg−1 Lb. buchneri NCIMB40788 (Fresh). Each additive treatment was based on fresh matter (FM). Results showed that all additives decreased pH values. All additives except Fresh decreased ammonia‐N content (p < .001). Both LP and LB increased lactic acid content (p < .001). Butyric acid content increased with FA (3 mL kg−1) and BA, but decreased with PA, PS, SB, FA (6 mL kg−1), AA, LP, LB (p < .001). FA (3 mL kg−1), AA (10 mL kg−1), PA, BA, PS, SB and Fresh improved aerobic stability (p < .001). After 8 days exposure to air, the pH value and yeast count were lower in FA (3 mL kg−1), BA (10 mL kg−1), SB treatments than in other treatments. Overall, AA outperformed all other additives in improving fermentation quality. Sodium benzoate and AA could be used as an effective additive to improve aerobic stability of L. chinensis silage.

Two additives (Silo Guard (SG) and propionic acid (PA)) were tested for their effects on the quality and aerobic security of sorghum–sudangrass hybrid silages (JC‐1 and WC‐2). Two sorghum–sudangrass hybrid varieties were harvested for ensiling without additives (CK) or after the following treatments: SG at 0·5% of fresh forage or PA at 0·5% of fresh forage, with three replicates per treatment. The addition of SG and PA both affected the fermentation quality and chemical composition of the silages by lowering pH and NH3‐N/TN and increasing lactic acid, the LA/TA ratio, WSC and CP concentrations compared with the untreated silages. In vitro DM digestibility (IVDMD), in vitro NDF digestibility (IVNDFD) and in vitro CP digestibility (IVCPD) were increased by SG in the JC‐1 silages and WC‐2 silages. Both additives improved the aerobic stability of sorghum–sudangrass hybrid silages. Furthermore, the additives reduced the mould counts and the aflatoxin and zearalenone levels compared with the untreated silages following aerobic exposure. Therefore, ensiling two sorghum–sudangrass hybrid varieties resulted in high‐quality silages. The addition of SG and PA improved silage quality, in vitro digestibility and aerobic security.