Effect of wilting and silage additives on silage quality of lucerne, red clover and legume-grass mixtures

摘要

Lucerne (Aiedicago sativa), red clover {Trifolium pratense) and the mixtures with grass are regarded difficult to ferment based on low contents of water-soluble carbohydrates (WSC) and nitrate as well as high buffering capacity (BC). The objective ofthis laboratory ensiling trial was to investigate the effects of 24, 48 and 72 hours wilting on dry matter (DM)-, WSC-content, BC as well as content of yeasts and lactic acid bacteria (LAB). Furthermore, the effects of chemical and biological additives on silage quality were investigated regarding the concentration of lactic acid, acetic acid and butyric acid, ethanol and ethyl esters depending on the level of wilting in ensiling material. In total 144 laboratory silages were analysed. With extended wilting period, the contents of WSC and BC decreased, whereas the contents of yeasts and LAB increased. A lower range of DM is associated with a higher risk of butyric acid formation, which requires the addition of chemical additives against Clostridia activity. Ihc results demonstrate the occurrence of volatile organic compounds (VOC), especially ethanol and ethyl esters, in legume silages. The DM content and silage additives affect the concentrations of ethanol, acids and esters. Elevated levels of ethanol and esters occur in silages with low DM. For the reduction of ethanol and ester formation, chemical additives against yeasts and bacteria are necessary.