Nutritive Value and Fermentation Parameters of Warm-Season Grass Silage

Abstract

The objective of this study was to investigate the nutritive value and fermentation characteristics of different species of warm-season grass silages not treated or treated with bacterial inoculants in the summer and fall. Nine forage species and cultivars, ‘Merkeron’ elephantgrass (Pennisetum purpureum Schumach.), ‘Mulato’ (Brachiaria sp.), ‘Argentine’ bahiagrass (Paspalum notatum Flugge), ‘Florico’ stargrass (Cynodon nlemfuensis Vanderyst), ‘Tifton 85’ bermudagrass (Cynodon sp.), ‘Jiggs’ bermudagrass (Cynodon dactylon L.), ‘Coastcross-2’ bermudagrass (Cynodon dactylon L.), ‘Florakirk’ bermudagrass (Cynodon dactylon L.), and ‘Floralta’ limpograss [Hemarthria altissima (Poir.) Stapf & C.E. Hubbard], were not treated (control) or treated with a microbial inoculant solution (Si-All, Alltech Inc., Nicholasville, KY) in a split-plot arrangement with 3 replicates. In the summer, NDF concentration was greater for the bermudagrasses than the average of other species (68 vs. 65%). Mulato had the lowest NDF concentration (57%) and the greatest in vitro true digestibility concentration (63%) compared with other treatments. Limpograss silage had the lowest pH (6.5) and the greatest lactic acid concentration (2.6%). Conversely, elephantgrass silage had decreased lactic acid concentration (0.1%) and greater pH (8.3) compared with the other species. Inoculated silages had lesser lactic acid concentrations than the control (0.62 vs. 1.84%). In the fall, elephantgrass had less in vitro true digestibility (60 vs. 65%) and NDF digestibility (44 vs. 52%) than the other species. Elephantgrass silage pH was less (7.2 vs. 8.8) and concentrations of total VFA (4.6 vs. 0.4%), lactic acid (1.5 vs. 0.2%), and acetic acid (2.1 vs. 0.2%) were greater than in the bermudagrasses. There was no effect of the inoculant on the nutritive value and silage fermentation variables in the fall.