chemical composition, rumen degradability and fermentation characteristics of fresh pragmates australis ensiled with different additives

introduction: pragmates australis (pa) (common reed) is a riverside perennial grass found in wetlands throughout temperate and tropical regions of the world. pa grows in many wetlands around rivers in iran. animal feed restriction is the main problem of iranian animal production systems and this feed resource can be fed to native livestock especially in rural areas. ensiling pa could improve its feeding value. the aim of this study, therefore, was to measure the chemical composition, gas production and rumen degradability characteristics of the fresh and ensiled pa with different additives. materials and methods: plant samples were harvested during growth season from the city of bojnoord,in iran. the pa samples were chopped and ensiled into airtight plastic bags as follow; 1)the fresh whole plant of pa as control (pa), 2) pa + 4% naoh, 3) pa+4% urea, 4) pa+10% molasses, 5) pa+4% urea +10% molasses and 6) pa+4% urea + 10% molasses +4% naoh (on dm basis). duration of the ensiling process lasted 60 days. chemical composition of the samples was measured through the ordinary lab methods. the in vitro gas production was determined at 2, 4, 6, 8, 12, 24, 36, 48, 72 and 96 hrs intervals after incubation. the in situ rumen degradability was also determined at 0, 2, 4, 8, 12, 24, 36, 48, 72, 96 hrs after incubation. the experiment data were analyzed in a completely randomized design. results and discussion: ndf and adf contents of the ensiled samples with urea were the highest whereas they were the lowest in the naoh treated samples. cp content of the urea treated pa was higher than other samples. ash content of the naoh treated forage was significantly (p<0.05) higher than other treatments. ammonia nitrogen level of urea-treated silage was highest whereas it was lowest for the pa treated with the molasses. the urea-treated pa samples had lowest rate of gas production. potential of degradability (pd) level of molasses and naoh treated silages were higher (p<0.05) than the control and urea-treated silages. the results of rumen dry matter degradability demonstrated that the quickly degradable fraction of pa treated with urea and molasses was significantly (p<0.5) highest among the silages whereas the value b fraction (slowly degradable) for urea-treated silage and urea and molasses treated silage were higher than other treatments. quickly degradable fraction of molasses treated samples was lowest among all treatment samples probably because of higher fermentation process in the silages. the c fraction (rate of degradation) of naoh treated forage was significantly (p<0.5) higher than that for other treatments whereas lowest level of c was observed in urea and molasses treated samples. according to the results urea-treatment led to higher crude protein content and naoh-treating was perfect for destruction of crude fiber of the pa samples. effective degradability (ed) of ndf was significantly (p<0.05) highest in naoh treated silage while pd of ndf was highest in pa treated with urea and molasses. gas production rate in all silages with different additives was higher (p<0.05) than the control samples. conclusion: it was concluded that the fresh pa can be harvested and treated with the appropriate supplements (e.g. molasses and naoh) and ensiled for subsequent better utilization in ruminant feeding specially in the areas with low rainfall and feed scarcity problem. quality of pa silage is directly affected by harvesting time and its lignification. therefore by harvesting at the appropriate time the pa could be a perfect forage or silage for ruminant animals.