Effect of ensiling time and temperature on the fermentaion quality and content of hydrocyanic acid in cassava roots and leaves

To use cassava as feed effectively, the influence of ensiling time and temperature on the fermentation quality and hydrocyanic acid content in cassava roots and leaves was investigated. The results showed, as the ensiling time prolonged, pH of cassava roots and leaves decreased, and they were 3.73 and 4.70 at 56 d, respectively. Lactic acid content of roots increased with the ensiling time, while that of leaves was the highest at 7 d. The ensiling temperature had no significant effects on the fermentation quality of cassava roots(P>0.05), and all roots silages had a pH near 3.70, while the leaves in silages at 30 and 40 ℃ had more lactic acid and lower pH than those at 20 ℃. The hydrocyanic acid content in cassava roots and leaves gradually reduced with ensiling time, and such reductions mainly took place in the first two weeks. As the ensiling temperature rose, the HCN content of roots and leaves significantly reduced (P<0.05). The detoxification rates of HCN were 55.82% and 63.56% for cassava roots and leaves at 40 ℃, respectively.