Abstract
Cup-plant (Silphium perfoliatum L.) has potential to produce high biomass and highly digestible forage in the wetlands where other productive forages do not grow or produce well. However, high moisture content at harvest is a considerable disadvantage of cup-plant for the production of high quality silage. This study was conducted to determine the effect of moisture content on the characteristics of cup-plant silage. Harvested cup-plant was ensiled in farm scale plastic bag silos and laboratory silos. In the plastic bag silos, first growth (FG) and regrowth (RG) cup-plant was harvested, wilted and ensiled. Dry matter content of FG and RG was 280 g/kg and 320 g/kg after 48 hr of wilting. The silage made with FG had pH 5.3 and 5.63 g/kg DM of acetate as a major volatile fatty acid. The composition of lactate, butyrate and acetate production was 1.0: 0.9: 2.3. The pH of silage made with RG was 4.5 and lactate was a major fermentation end product (16.8 g/kg DM). In the laboratory silos, wilted and unwilted first growth cup-plant material was ensiled to compare the early fermentation end products at days 2, 4, 11, and 40. Wilting increased dry matter content by 42% in the harvested material. Wilted silage showed about one unit lower pH until day 11. The contents of ammonia nitrogen and acetate were higher in un wilted silage, while that of lactate was higher in wilted silage (p<0.05). Butyrate and propionate were not detected in the wilted silage until day 40. We conclude from the results that moisture control is essential for the production of high quality cup-plant silage and high pH of cup-plant silage is due to low concentrations of fermentation end products.