Abstract:
Silage is the compressed and fermented green forage crops under anaerobic condition, usually in a silo. Crop residues can be used as feed for cattle during the dry season by ensiling them as silage. The aim of this study is to identify the combination of various crop residues to produce good quality silage. Samples of silage produced from individual crop residues and different combinations of crop residues were collected from farmers who produced silage in the Northern Province of Sri Lanka from January to March 2017. Twenty samples of silage from ten different individual and combinations of crop residues with fodder trees in two replicates were analyzed for sensory evaluation, pH, Ammonium-N, lactic acid and total acidity of silage in the field itself using silage quality detection field test kit and the crude protein content was measured using standard procedure in the laboratory. Based on the results, though the silage made from the combination of Sorghum bicolor (sugargraze) + Oryza sativa (paddy) straw + Gliricidia sepium (gliricidia) leaves showed the highest percentage of crude protein of 21%, the fermentation quality was reported to be low. When considering fermentation quality, the silage made from Pennisetum purpureum (hybrid napier grass (co-3)), Zea mays (maize), Sorghum bicolor (sugargraze), and from the combinations of Sorghum bicolor (sugargraze)+ Borassus flabellifer (palmyra) leaves, Sorghum bicolor (sugargraze) + Oriza sativa (paddy) straw + Gliricidia sepium (gliricidia) leaves, Sorghum bicolor (sugargraze) + Thespesia populnea leaves + Borassus flabellifer (palmyra) leaves+ Gliricidia sepium (gliricidia) leaves and Zea mays (maize) + Gliricidia sepium (gliricidia) leaves showed the excellent quality while the silage made from Oriza sativa (paddy) straw+ urea with poor quality. The highest lactic acid concentration was recorded in the silage made from the combinations of Sorghum bicolor (sugargraze) + Borassus flabellifer (palmyra) leaves and Sorghum bicolor (sugargraze) + Thespesia populnea leaves+ Borassus flabellifer (palmyra) leaves + Gliricidia sepium (gliricidia) leaves. The results revealed that the silage produced with the combinations of crop residues consisting of Borassus flabellifer (palmyra) leaves was with excellent fermentation quality. Further investigation is recommended to find out the quantified proportion of Barassus flabellifer (palmyra) leaves with other crop residues and fodder trees that could yield the best quality of silage.