Chhay Ty et al., 2001. Livest. Res. Rural Dev., 13 (2)

An experiment was designed at laboratory scale to study the effect of time (0, 14, 28, 42 and 56 days), origin of the cultivar (Kampong Cham province and Chamcar Daung, Phnom Penh) and levels of added sugar palm syrup (2.5, 5 and 7.5% in fresh basis) for ensiling of cassava foliage. Average air temperature was 27 °C, and crude protein content of both sources of cassava foliages was 18.1 and 22.2% in dry basis, respectively.

There was no significant interactions between factors studied. The overall pH profile of the ensiled material showed a sharp drop at  14 days after ensiling ( from 6.10 to 3.73), with slight fluctuations thereafter. A significant effect (P<0.001 ) of sugar palm syrup concentration on pH values was found in favour of 5% addition of the source of carbohydrate. There was a significant correlation (R² = 0.31; P<0.001) between pH values and neutralizing capacity of the preserved  material.

The cyanide concentration of the silages exhibited a significant negative (P<0.001) linear dependence on time. In spite of the fact that the Kampong Cham variety had a higher initial HCN content (86 mg/kg fresh foliage) as compared to that from Chamcar Daung (73 mg/kg fresh leaves), there were no differences in HCN content after 56 days of ensiling (overall value, 20 mg/kg fresh foliage).

It is suggested the use of sugar palm syrup at the level of 5% in the preparation of cassava foliage silages in Cambodia. According to results from the present experiment, the HCN content is in the range of safe utilization for monogastric animals such as pigs, after 56 days of ensiling the material.