THE EFFECTS OF INCLUSION OF SILVERLEAF DESMODIUM (Desmodium uncinatum) FORAGE AND MOLASSES ON NAPIER GRASS (Pennisetum purpureum) SILAGE QUALITY

Abstract

Tropical grasses such as Napier grass (Pennisetum purpureum) have high dry matter yield but are low in protein content. One way of overcoming the low protein of Napier is to combine the grass with herbaceous forage legumes during silage making. Conserving grass-legume forage as silage is an option that alleviates feed constraints during dry periods. The objective of the study was to investigate the fermentation quality and nutritive value of Napier grass ensiled with Silverleaf desmodium (Desmodium uncinatum) forage and molasses as an additive. Existing Napier and Silverleaf forages were harvested, chopped to 2.5 cm pieces and ensiled for eight weeks in mini silos. The legume and grass were mixed in the following ratios 0:100, 20:80 and 50:50, respectively, whilst molasses was added at levels of 3% and 5% (w/w). The pH ranged from 3.86 to 5.03, indicating good fermentation quality of the silage. The best fermentation was observed in 5% molasses and 20% Silverleaf silage which had significantly (P < 0.05) the lowest pH of 3.86 whilst Napier alone silage had the highest pH of 5.03. The dry matter content of the silages differed significantly (P < 0.05) ranging from 22.58% to 26.18%. The CP content of the Napier alone silage was 7.4 %, which was improved (P < 0.05) to 10.85% and 11.37% by the addition of 20% and 50% Silverleaf, respectively. There were no significant (P > 0.05) differences in the ash and organic matter content of the silages. The crude fibre content was significantly (P > 0.05) high in silages containing higher amounts of Silverleaf. The inclusion of molasses improved the fermentation characteristics of Napier grass silage whilst the inclusion of the legume Silverleaf improved the protein content of Napier grass silage.