Possibilities to Avoid Growth of Clostridia and/or Fungi in Wilted Silage by Use of Organic and Inorganic Salts

The hygienic quality of silage will be of great importance in the future as poor quality not only influences the animal production but also the animal health and the food quality. This study examined the impact of mixtures of sodium benzoate (NaB), sodium nitrite (NaN), hexamine (HMTA), sodium propionate (NaP), sodium bisulphite, and propionic acid on low and high wilted clover/grass. The silage (crop wilted to 300 or 600 g DM kg-1 of fresh weight) consisted of about 50% red clover (Trifolium pratense) and 50% timothy (Phleum pratense) and the study covered 7 additive treatments. The forage was un-chopped and ensiled in two types of silos: 25 litre stainless laboratory silos, stored during 100 days and 1,7 litre glass silos in 14 days. In both studies samples were taken for chemical and microbial analyses. High contents of nitrite could influence animal health and were of specific interest. Residual nitrite contents were higher in silage after 14 days than 120 days storage but both concentrations were negligible. The additives highly restricted growth of yeast in all treatments but the control silage. As a consequence of low growth of yeast in the silage, the production of ethanol was significantly lower compared to the control silage. Even the count of clostridia spores was significantly restricted in treated silages and so was the reduction in DM - losses except for treatment E. The conclusion is that sodium nitrite in combination with hexamine effectively prevented clostridia growth as well as sodium benzoate restricted yeast growth. The nitrate / nitrite concentration were reduced already after 14 days