Cellulase and Bacterial Inoculant Eþects on Cocksfoot and Lucerne Ensiled at High Dry Matter Levels

Cellulase and Bacterial Inoculant Eþects on Cocksfoot and Lucerne Ensiled at High Dry Matter Levels

Cellulase and Bacterial Inoculant Eþects on Cocksfoot and Lucerne Ensiled at High Dry Matter Levels

Abstract

Limited information exists on the response of grass and legume silage
to enzyme and bacterial inoculant treatments when wilted to drier than desired
conditions. This study was undertaken to evaluate the impact of cellulase (from
T richoderma longibrachiatum) application rate, when combined with a bacterial
inoculant (L actobacillus plantarum and Pediococcus cerevisiae), on the fermentation characteristics of cocksfoot (Dactylis glomerata L) and lucerne (Medicago
sativa L) ensiled at high dry-matter concentrations. Forages were wilted to near
600 g dry matter kg~1 and cellulase, combined with inoculant, was applied at
0É30 ml kg~1 herbage and at two, four and eight times this concentration (at
least 2500 IU ml~1). Cellulase was also applied alone at 0É60 ml kg~1. Wilted
forages were ensiled in laboratory silos for 60 days. E†ect of cellulase application
rate on neutral detergent Ðbre concentrations of the silages was small and inconsistent. Averaged across species, only the intermediate cellulase concentrations decreased neutral detergent Ðbre concentration (P\0É082). The limited cell-wall
degradation was probably related to the high silage dry-matter and lignin concentrations. Cellulase combined with inoculant increased total fermentation, when averaged across species. In cocksfoot, cellulase combined with inoculant
decreased pH and concentration but increased the lactic : acetic acid NH3-N
ratio of control silage, with most of the e†ect caused by the inoculant. Cellulase
applied alone to lucerne caused a higher lactic : acetic acid ratio than the control
or when combined with the inoculant at the same cellulase rate. Thus, the e†ect
of cellulaseÈinoculant mixtures on silage quality varied among plant species, with
cocksfoot generally more responsive than lucerne.

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