Fermentation Quality of Round-Bale Silage as Affected by Additives and Ensiling Seasons in Dwarf Napiergrass (Pennisetum purpureum Schumach)

Satoru Fukagawa,Ikuo Hattori,Yasuyuki Ishii

doi:10.3390/agronomy6040048

Abstract

Fermentation quality of dwarf napiergrass (Pennisetum purpureum Schumach) was estimated for additives lactic acid bacteria and Acremonium cellulase (LAB + AC), fermented juice of epiphytic lactic acid bacteria (FJLB), and a no-additive control in 2006 via two ensiling methods—round-bale and vinyl-bag methods in 2006—and via two ensiling seasons—summer and autumn of 2013. Fermentation quality of dwarf napiergrass ensiled in the summer season was improved by the input of additives, with the highest quality in LAB + AC, followed by FJLB; the lactic acid content was higher, and the pH and sum of the butyric, caproic, and valeric acid contents were lower, resulting in an increase in the V-score value by each additive. The ensiling method in autumn without additives affected fermentation quality, mainly due to the airtightness, which was higher for round-bale processing than in vinyl bags, even with the satisfactory V-score of 72. Fermentation in round bales without additives had a higher quality in autumn than in summer, possibly due to the higher concentration of mono- and oligo-saccharides. Thus, it was concluded that dwarf napiergrass can be produced to satisfactory-quality silage by adding LAB + AC or FJLB in summer and even in the absence of additives in autumn.

Highlights

Superior properties of a dwarf variety of late-heading type napiergrass (Pennisetum purpureumSchumach) were verified in our previous research, such as a high winter survival for several years [1]and a high palatability of silage compared with sorghum or Sudangrass [1], and a satisfactorily high total digestible nutrient (TDN) concentration of silage of 552–593 mg/g in two digestion trials with Japanese Black breeding cows [1]
Since dwarf napiergrass is highly ranked in nutritive value among tropical grasses, the silage produced from the crop is available for preserved roughage in a winter season
The dry matter (DM) yield tended to increase and leaf bade (LB)/ST tended to decrease with increases in plant length

Summary

Introduction

Superior properties of a dwarf variety of late-heading type napiergrass (Pennisetum purpureumSchumach) were verified in our previous research, such as a high winter survival for several years [1]and a high palatability of silage compared with sorghum or Sudangrass [1], and a satisfactorily high total digestible nutrient (TDN) concentration of silage of 552–593 mg/g in two digestion trials with Japanese Black breeding cows [1]. Superior properties of a dwarf variety of late-heading type napiergrass Dwarf napiergrass can be utilized as a perennial without reestablishment every spring in Northern Kyushu, Japan, and is a promising forage for beef cow-calf-producing farmers in the region [1]. Dwarf napiergrass shows high winter survival imposed by the mid to late November closing cut in the region and even on remote islands [2]. Since dwarf napiergrass is highly ranked in nutritive value among tropical grasses, the silage produced from the crop is available for preserved roughage in a winter season. The fermentation quality of round-bale silage of dwarf napiergrass was evaluated as unstable due to low water-soluble carbohydrates, compared with other tropical grasses, which remains to be solved for sustaining the long-term quality of the silage.

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