Due to the development of early maturing maize hybrids tlie area of maize grown for silage in the UK has increased markedly. Although there is an important positive relationship between maize silage DM content and silage intake, which farmers should try and take advantage of, high DM crops are difficult to consolidate and as a result are more susceptible to aerobic instability. As a result farmers are tending to harvest crops earlier to reduce the risk of aerobic instability but in so doing they sacrifice silage intake. The problem of aerobic instability exists not only during the winter feeding period but also when maize silage is used as a buffer feed during the summer. The aim of the current study was to determine the effect of a blend of partially neutralised organic acid salts based on propionic and formic acid on the DM loss during ensiling, fermentation characteristics, nutritive value and aerobic stability of maize silage.