Nutritional and fermentation quality of ensiled willow from an integrated feed and bioenergy agroforestry system in UK

Titre

Nutritional and fermentation quality of ensiled willow from an integrated feed and bioenergy agroforestry system in UK

Suomen maataloustieteellisen seuran tiedote

Créateur

Jo Smith

Kaisa Kuoppala

David Yanez-Ruiz

Katharine Leach

Marketta Rinne

Sujet

Condensed tannins

Digestibility

Feed value

Fermentation quality

Salix viminalis

Silage

Date

2012

uri

https://journal.fi/smst/article/download/75342/36788

Résumé

Agroforestry, the integration of trees and agriculture, is valued as a multifunctional land use approach that
balances the production of commodities (food, feed, fuel, fibre etc.) with non-commodity outputs such as
environmental protection and cultural and landscape amenities.
In this study, the possibilities for fodder production from a short rotation coppice of willow (Salix
viminalis) used for wood chips to produce energy were investigated. The nutritional value and ensilability
were assessed from first year regrowth of willow harvested on 29 June 2011 at Wakelyns Agroforestry,
Suffolk, UK. The willow branches with a stem diameter less than 8 mm were manually harvested from 4
plots in two replicates. From 2 plots, another sample was prepared including leaves only. Both dried raw
material and silage samples ensiled in evacuated polyethylene bags were analyzed.
The crude protein concentration was relatively high in leaf + stem silage (182 g/kg dry matter
(DM)) and even higher in leaf only silage (219 g/kg DM) and the fibre concentration was relatively low.
However, the organic matter digestibility determined by in vitro pepsin-cellulase method was low (0.421
for leaf + stem silage and 0.511 for leaf only silage) and it cannot be considered as a suitable feed for
lactating dairy cows. However, it might be suitable for other animal groups with lower energy
requirements.
The appearance and smell of the silage samples at opening of the vacuum plastic bags was rather
pleasant with minor deteriorations (probably yeasts) visible. The extent of fermentation was low and pH
high (5.79) for a rather low DM material (DM concentration 276 g/kg). The water soluble carbohydrates
of the raw material (35 g/kg DM) and the residual water soluble carbohydrate concentration in silages
was relatively low, which at least partly explains the restricted production of fermentation acids. The
fermentation profile was heterofermentative (acetic acid dominated instead of lactic acid). The
concentrations of total condensed tannins fractions were almost twice as high in the leaf only silage
compared to leaf + stem silage.
Although the feed values of willow were low, it may have a role in multifunctional systems,
where it can provide additional values in grazing situations such as self-medication and microclimate
benefits. For easy and efficient use in animal production, controlled browsing might be used; otherwise
methods for harvesting and preservation need to be developed. There seems to be some scope for ensiling
willow material.
This work is part of an EU FP7 funded project “Sustainable organic and low input dairying”
(SOLID, KBBE.2010.1.2-02). For more information on the project, see www.solidairy.eu.

numéro

30

Langue

en