Effects on methane production
Following the composition analysis, laboratory fermentation experiments were conducted to link grape marc composition with ability to reduce methane production. Results showed that tannin concentration, tannin composition and overall fatty acid content were the most important factors influencing methane reductions.
Steam distilled red marc and ensiled white marc parcels were then selected for feeding trials with dairy cattle. Further trials with sheep are planned to take place at the University of Melbourne in 2014/2015, investigating two different dose rates of grape marc. Results from these animal trials will be published at the conclusion of the project.