Submitted to: Asian Australasian Journal of Animal Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2000
Publication Date: N/A
Citation: Interpretive Summary: Cup-plant is a native forage with great potential because it will grow under wet conditions and can produce good yields of high nutritional quality. However because of its thick stems, it dries slowly and cannot be preserved as a hay. Preservation must be by ensiling, but little is known about its ensiling characteristics. We ensiled cup-plant in both laboratory yand farm-scale bag silos. In the laboratory silos, fresh cut cup-plant and cup-plant that had been field-dried for one day were ensiled. One day of field-drying still resulted in a crop that was 80% moisture. Both the fresh cut and wilted cup-plants produced poor quality silages with high pH. In the farm-scale silages, cup-plants were dried for two days before ensiling, resulting in moisture contents of 68 and 72%. Only the 68% moisture silage fermented well, producing a low pH (4.5). Thus while cup-plant is an attractive alternative forage, it must be field-dried sufficiently (<70% moisture) in order to guarantee a good silage fermentation, information critical to farmers and farm advisors working with this crop.
Technical Abstract: Cup-plant (Silphium perfoliatum L.) has the potential to produce high levels of digestible forage in wet conditions where other productive forages do not grow well. However, the high moisture content of the cup-plant at harvest is a disadvantage for producing 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) was wilted for 48 h and ensiled. The dry matter (DM) content of FG and RG was 280 and 320 g/kg, respectively. The silage made with FG had a pH of 5.3, and the primary fermentation acid was acetate ( 5.6 g/kg DM). The pH of the silage made with RG was 4.5, and lactate was the major fermentation end product (16.8 g/kg DM). In the laboratory silos, wilted (24 h) and unwilted first growth cup-plant was ensiled, and silos were analyzed after 2, 4, 11 and 40 d ensiling. Wilting increased DM content from 140 to 200 g/kg. The wilted silage had a 1 unit lower pH until day 11. The pH of both treatments were unsatisfactory at 11 and 40 d (6.7 to 7.1). Ammonia nitrogen and acetate concentrations were higher in the unwilted silage while lactate was higher in the wilted silage (p < 0.05). Butyrate and propionate were present only in the day 40 unwilted silages. Overall, the only silage of high quality was the driest silage, the farm-scale RG silage. Sufficient wilting is clearly necessary to produce a good fermentation in cup-plant silage.