The effect of formic acid on the fermentation of ryegrass ensiled at different stages of growth and dry matter levels

In the first experiment the buffering effect of Italian and perennial ryegrass to fonnic acid was determined with three varieties (Leda, S24 and Presto) cut at weekly intervals throughout the growth cycle. The buffer curves showed no significant differences between the three varieties at any one stage of growth and the results were combined to produce regression equations predicting pH values for the three ryegrasses cut at first ear emergence (e.e.), 50% e.e. and 100% e.e. after addition of formic acid. In the second experiment Italian ryegrass was harvested at three stages of growth, wilted to four different DM contents and ensiled in laboratory silos with five levels of formic acid. The interaction of stage of growth, formic acid level and DM content on the water-soluble carbohydrates, ethanol and volatile N contents of tbe resultant silages is discussed.