Chemical composition of silages treated with some volatile fatty acids,with special reference to the changes in sugars

In eight separate experiments with laboratory silos, silages were prepared with 50 mmol caproic (nC₆), isocaproic (iC₆), valeric (nC₅) and isovaleric (iC₅) acid additions per kg Italian ryegrass or cocksfoot, and stored at 25°C for 70 days. In the nC₆ and iC⁶ treatments, fermentation was consistently inhibited, and also the contents of water-soluble carbohydrates (WSC) were considerably higher in the silages than in the grasses. This increase in WSC was partly explained by the increase in glucose but the difference between WSC and “glucose + fructose” was clearly larger in the silages than in the grasses. In the nC₅ and iC⁵ treatments, various results were obtained; in some cases, presumably due to high dry matter content, fermentation was inhibited and WSC increased, while, in one case, fermentation was improved with higher lactic acid and lower butyric acid production than in the control silage. According to the results of five experiments with bag silos, although the inhibition of fermentation was observed by the treatment with nC₆, little or no increase in WSC during ensilage was found.