Weinberg, Z.G., Forage Preservation and By-Products Research Unit, The Volcani Center, Bet Dagan, 50250, Israel
Ashbell, G., Forage Preservation and By-Products Research Unit, The Volcani Center, Bet Dagan, 50250, Israel
Hen, Y., Forage Preservation and By-Products Research Unit, The Volcani Center, Bet Dagan, 50250, Israel
Azrieli, A., Forage Preservation and By-Products Research Unit, The Volcani Center, Bet Dagan, 50250, Israel

The effect of a new strain of Propionibacterium shermanii (PAB), applied at ensiling, on the aerobic stability of wheat and sorghum silages was studied in several experiments under laboratory conditions. In the one experiment with wheat and in those with sorghum a lactic acid bacteria (LAB) inoculant (Lactobacillus plantarum and Pediococcus cerevisiae) was also included. After treatment, the chopped forages were ensiled in 1.5-L anaerobic jars which were sampled in triplicate on predetermined dates to follow fermentation dynamics. At the end of the experiments, the silages were subjected to an aerobic stability test. The PAB inoculant improved the aerobic stability only in one experiment with wheat, in which the decrease in pH was very slow; the final pH remained relatively high (4.5). The PAB-treated silages contained 19.5±2.0 g of propionic acid per kg of dry matter. In the experiments with sorghum, the control and PAB-inoculated silages were stable, whereas LAB-inoculated silages deteriorated. The results suggest that PAB can survive in and improve the aerobic stability of only slow-fermenting silages which are prone to aerobic deterioration. © 1995 Society for Industrial Microbiology.