Abstract:
The present study investigated the nutritional and fermentative characteristics of silage from
sweet potato vines (SPV), Napier grass (NAP) using maize bran as a source of fermentable
carbohydrates. Chopped SPV, Napier grass NAP and their 1:1 mixture (SPV-NAP) were
thoroughly mixed with finely ground maize bran followed by hand compacting into 1 kg
laboratory sized plastic micro-silos in three replicates. Three laboratory micro-silos for each
treatment were opened after a 60 day fermentation period. The means were compared using
PROC GLM procedures of SAS (2003). The chemical composition of silage significantly
(P<0.05) varied with the type of material ensiled. Silage dry matter (DM) content varied
(P<0.05) with type of material ensiled. The DM content of SPV and SPV-NAP silage was higher
(P<0.05) than that of NAP silage. Crude protein was higher (P<0.05) in SPV-NAP silage as
compared to SPV and NAP silage. Silage pH of 3.84 for the SPV and SPV-NAP silages was
lower (P<0.05) than the pH (4.73) NAP silage. The ammonia-Nitrogen content of the silage
followed a similar trend with that of pH, with the highest ammonia yield recorded for NAP
silage. The lactic acid content was significantly (P<0.05) higher in SPV silage (6.1%) than the
4.5% on DM basis for NAP and SPV-NAP silage. The lactic acid: acetic acid ratio did not
significantly differ (p<0.05) across the ensiled material. These results indicated that SPV can be
ensiled together with NAP under circumstances where neither of the two is insufficient quantities
for silage production without compromising the silage quality and storability. |
