Enzyme, inoculant, and formic acid effects on silage quality of orchardgrass and alfalfa

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 Trichoderma longibrachimm) application rate, when combined with a bacterial inoculant {Lactobacillus 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' and enzyme, combined with inoculant, was applied at 0.30 ml kg'' herbage and at two, four and eight times this concentration (at least 2500 lU ml *). Enzyme was also applied alone at 0.60 ml kg'. Wilted forages 'IDepartment of Agronomy, Iowa State University and ^Agriculture Research Service, USDA, 1577 Agronomy Hall, Ames, lA 50011, USA • Joint contribution of the Field Crops Research Unit and US Dairy Forage Research Center of USDA-ARS, and Iowa State University. Journal Paper Number J-16517 of the Iowa Agriculture and Home Economics Experiment Station, Ames, lA. Project Number 2709. t To whom correspondence should be addressed. Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable. 21 were ensiled in laboratory silos for 60 days. Effect of enzyme application rate on neutral detergent fibre concentrations of the silages was small and inconsistent. Averaged across species, only the intermediate enzyme concentrations decreased neutral detergent fibre concentration (P = 0.082). The limited cell-wall degradation was probably related to the high silage dry-matter and lignin concentrations. Enzyme combined with inoculant increased total fermentation, when averaged across species. In cocksfoot, enzyme combined with inoculant decreased pH and NHj-N concentration but increased the lactic:acetic acid ratio compared with control silage, with most of the effect caused by the inoculant. Enzyme applied alone to lucerne caused a higher lactic:acetic acid ratio than the control or when combined with the inoculant at the same enzyme rate. Thus, the effect of enzyme-inoculant mixtures on silage quality varied among plant species, with cocksfoot generally more responsive than lucerne.