THE EFFECT UPON FERMENTATION AND NUTRITIVE-VALUE OF SILAGES PRODUCED AFTER TREATMENT BY 3 DIFFERENT INOCULANTS OF LACTIC-ACID BACTERIA APPLIED ALONE OR IN COMBINATION

Silages were made from the first cut of a predominantly perennial ryeg rass sward. The silages were either untreated (W) or treated with form ic acid (3 1 t-1, F) or with 10(6) lactic acid bacteria (LAB) g-1 gras s of each of three strains alone (A, Lactobacillus plantarum MTD1; B, Pediococcus species 6A2; C, L. plantarum 6A6) or in combination (AB, A C) to give seven treatments. The silage fermentation in 10-kg silos wa s followed chemically and microbiologically and the nutritive value of selected treatments evaluated using 2-t silos. The control silage (W) fermented well. Addition of formic acid restricted fermentation and p roduced a silage with a high ethanol concentration. After day 4, all i noculated silages had lower pH values and higher lactic acid concentra tions and a higher ratio of lactic acid to acetic acid than the contro l silage. Chemically there was little difference between the inoculate d silages in terms of final composition. Microbiologically the LAB app lied in treatments B and C dominated the LAB populations in those sila ges when applied alone; however, they were suppressed when applied in combination with inoculant A. When fed to sheep, the intake of the for mic acid-treated silage was significantly (P < 0.01) lower than that o f the other silages and the intake of silage treated with inoculant A significantly (P < 0.001) higher than that of silages treated with ino culants B and C. The apparent organic matter (P < 0.001) and nitrogen (P < 0.01) digestibilities of the formic acid-treated silage were also significantly lower than those of the other silages.