Effect of urea and molasses supplementation on quality of cassava top silage

Abstract

The aim of the study was to evaluate the nutritive value and fermentation efficiency of cassava top silage using in vitro gas production technique. The four-month plants were harvested, chopped into 2–3 cm pieces and ensiled with 0, 0.5 and 1% urea (U), and 0, 0.5, 1 and 2% molasses (M) (on the basis of the crop dry matter (DM)). Silage pH increased with U supplementation but decreased by addition of 2% of M, so the lowest pH values were observed in: U0M0–2 and then in U0.5M2 and U1M2 groups. The U supplementation increased crude protein content in cassava top silage in a dose-dependent manner. There was observed U × M interaction for neutral and acid detergent fibre contents (NDF and ADF, respectively) – when added together the M decreased these parameters in a dose-dependent manner, and the lowest value of NDF was observed in U1M2 group, and of ADF – for U0M2, U0.5M2 and U1M2 groups. The cumulative gas production was increased when either U or M were added, and the highest value was observed in U0.5M2 and U1M2 groups. In addition, the true digestibility was increased when M was added and the NDF digestibility was the highest in M2 groups. Fermented pH was increased by U supplementation while protozoa populations were similar among treatments. So, supplementation with 0.5–1% of U and 2% of M may increase cassava top silage quality and the in vitro fermentation efficiency. However studies evaluating cassava top silage influence on animal growth performance are recommended.