Inoculant effects on red clover silage: fermentation products and nutritive value

The study investigated effects of five different microbial inoculants on silage fermentation and nutritive value. Silage was prepared from red clover-rich material with dry matter content after 24 hours of wilting of 170 g kg I 1 for the first cut and 430 g kg I 1 for the second cut. Tests with five different commercial inoculants were based on different strains of Lactobacillus plantarum which were used alone or in combinations with other lactic acid bacteria (1/BO, 2/BI, 3/SI, 4/EC, 5/BM), and chemical additive (CHEM) were used. Six commercial additives were compared with the untreated control. The additives were applied to fresh forage at the levels recommended by the manufacturers. Chemical compositions of the first and second cut of red clover were significantly different I crude protein 176 g kg I 1 and 143 g kg I 1 ; NDF 366 g kg I 1 and 503 g kg I 1 DM respectively. In the first trial, silages treated with 2/BI had lower levels of acetic acid 25.5 g kg I 1 and ethanol 8.0 g kg I 1 compared to the control values of 35.6 g kg I 1 and 11.6 g kg I 1 (P<0.05). Otherwise, the pH, and contents of ammonia nitrogen, ethanol and organic acids were no different from the control silage. In the second trial, silage treated with 1/BO and 4/EC showed the highest contents of lactic acid. Compared to the untreated control silage, the acetic acid content was lower in silages treated with 2/BI, 3/SI and 5/BM (P<0.05). The lactic acid:acetic acid ratio was higher in inoculated silages: for 1/BO, 2/BI; 3/SI, 4/EC and 5/BM it was 2.73; 2.17; 1.98; 2.03 and 2.87, respectively. The same ratio for the control silage was 1.83. All commercial inoculants improved the fermentation quality of red clover silage under the conditions stated. No differences were found between dry matter in vitro digestibility of the inoculated and the control silage for both the first and second cut. Digestibility of the red clover silage treated with CHEM was higher than that of the control silage by 4.6% for the first cut and by 7.3% for the second cut (P<0.001).