Ensiling and nutritive value of kenaf (Hibiscus cannabinus)

The apical portion of the kenaf plant was harvested at full bloom, chopped and ensiled for the purpose of assessing its suitability for ensiling, the progression of fermentation, and its nutrititive value. The effect of addition of dried sugar-beet pulp to the kenaf forage prior to ensiling was also tested by preparing silages with 0% (P00), 5% (P05), and 10% (P10) of dried beet pulp (fresh weight basis). Silages P05 and P10 showed increases in dry matter (DM) vs. silage P00 (from 254 to 318 g kg(-1)) and decreases in NDF (from 625 to 572 g kg(-1) DM). The fermentation characteristics of the silages were slightly improved by the addition of dried beet pulp with decreases in pH (from 3.89 to 3.72) and ammonia-N (from 109.3 to 78.9 g kg(-1) of total N). No effluent losses were observed, while fermentation losses slightly decreased due to the addition of beet pulp. Fermentation was most active between 24 and 96 h after ensiling. Digestibility and nutritive value were low in the pure kenaf silage and increased in the mixed silages (DM digestibility: 0.46, 0.54 and 0.56; energy value: 0.47, 0.56 and 0.61 UFL kg(-1) DM, in P00, P05 and P10, respectively). Crude protein digestibility was low in all silages. The P00 silage was unpalatable and often even refused by the ewes. The voluntary intake of the mixed silages was slightly higher but always lower than the estimated maintenance requirement. In conclusion, the apical portion of the kenaf plant harvested at full bloom proved to be conservable through ensiling, and the addition of dried pulp slightly improved its conservability and nutritive value. However, the low nutritive value and the low voluntary intake of the silages showed them all to be inadequate for the feeding of productive livestock. (C) 1998 Elsevier Science B.V.