Effects of Molasses and Storage Period on the Chemical, Microbial and Fermentation Characteristics of Guinea Grass - Cassava Leaves Silage
The study was conducted to determine the effects of molasses and storage periods on the chemical composition, microbial and fermentation characteristics of silage produced from guinea grass and cassava leaves mixture. Guinea grass was harvested at 2 months regrowth from an established pasture and cassava tops collected immediately after root harvest consisting of only the tops with the green stem and its leaf canopy. The forages were wilted and thoroughly mixed in the ratio of 70:30 (guinea grass: cassava leaves); mixed with molasses at the rate of 0, 2, 4 and 6 % and ensiled for 30 and 60 days respectively for fermentation. The DM, CP, NDF, HCN and tannin contents of the ensiled guinea grass and cassava leaves significantly reduced as the level of molasses addition and storage period increased. The acetic acid fermentation was high in the 0, 2, 4 and 6% molasses addition with values ranging from 40.2 to 42.4 g/kg DM while the lactic acid content was only 18.4 to 30.3 g/kg DM at the 0% molasses addition. However, lactic acid fermentation increased significantly as both the storage periods and molasses addition increased from 0 to 60 days. The highest bacterial count (8.4 log cfu/g) was recorded at the 0% molasses addition and this significantly reduced as molasses addition increased from 0 to 6% and as the ensiling periods elongate from 0 to 60 days. However, a sharp decline in fungi count was observed with increase in the percentage of molasses added. The bacteria isolated from the silage were Staphylococcus aureus, Streptococcus spp., Enterobacter spp., Proteus spp., Escherichia coli and Lactobacillus buchneri. It is concluded that ensiling mixture of guinea grass and cassava leaves with molasses increased lactic acid and suppressed the production of acetic and butyric acids with drastic reduction in microbial load.
Keywords: Guinea grass, cassava, storage period, molasses, fermentation, chemical composition