Grass size and butterfly pea inclusion modify the nutritional value of elephant grass silage

Abstract

The objective of this work was to evaluate the nutritional value of silages from tall-sized and dwarf elephant grass (Pennisetum purpureum) genotypes, intercropped or not with butterfly pea (Clitoria ternatea). The experiment was performed in randomized complete blocks, in a 4x2 factorial arrangement (four genotypes × two cropping systems). The genotypes intercropped or not with butterfly pea were: IRI-381 and Elephant B, tall sized; and Taiwan A-146 2.37 and Mott, dwarf. Forage was harvested 60 days after regrowth. In the silage from Mott grass intercropped with butterfly pea, lower contents of lignin (78.1 g kg^-1), neutral detergent fiber (636.0 g kg^-1), and neutral detergent insoluble protein (13.15 g kg^-1), besides a greater dry matter recovery (873.3 g kg^-1), were observed. The silage from Taiwan A-146 2.37 intercropped with the legume showed a greater crude protein content (136.1 g kg^-1). In both silages, the ammonia nitrogen contents were quite reduced (26.4 g kg^-1). However, greater residual water-soluble carbohydrate contents were observed in the silages from the intercrop (1.85 mg g^-1) and from the Mott grass monocrop (1.51 mg g^-1). Moreover, there was a lower in vitro dry matter digestibility (676.7 g kg^-1) for the silage from the intercrop. Dwarf genotypes increase the nutritional value of elephant grass silage, compared with the tall-sized ones. Intercropping with butterfly pea improves silage fermentation characteristics, despite reducing its digestibility. Therefore, the ensilage of dwarf Mott elephant grass intercropped with butterfly pea shows more promising results.