THE AWRI is currently in the first year of a project investigating the practicalities of using steam distilled grape marc as a supplement in livestock feed to reduce methane emissions.
This work builds on research which has demonstrated a reduction in methane emissions from ruminant animals that were fed grape marc.
The new project is working on designing practical solutions for grape marc storage and feeding all year round in order to make the concept feasible in a commercial setting.
One of the challenges to be overcome is the tendency for mould to grow on grape marc.
When stored aerobically, mould can grow on grape marc within a 24 to 48 hour window post-pressing.
During anaerobic storage, on the other hand, acids are produced which preserve the marc and prevent mould growth.
This then allows the product to be stored over long periods of time.
The AWRI is currently trialling a number of different anaerobic storage techniques and treatments to identify the most practical and effective option.
Using buckets as mock mini-silos, the project team tested a number of common agricultural feed additives to investigate their ability to prevent mould formation during storage; however only a select few improved the stability of the stored grape marc.
On a larger scale, a common method of storing grain has been adapted for grape marc storage.
The Grain Bag stores grape marc in a compacted form which removes excess oxygen and gives the desired anaerobic environment.
Using a similar principle, grape marc was also made into bales, both as 100 per cent grape marc and combined with other stock feed.
The baling system produces compact film wrapped bales, weighing between 750 and 1000 kg.
A range of bales was generated, combining grape marc with different fibrous forages to determine the optimal bale content for structural integrity and minimisation of on-site waste.
Check out this video to see the process of baling 100 per cent grape marc.
Once an optimal grape marc storage and treatment method has been identified, the project will move on to a larger scale trial with a commercial feedlot.
The AWRI project ‘Using grape marc as a feed additive in commercial settings’ is supported by the Australian Government.
For more information contact Kieran Hirlam, Project Technician Commercial Services:
P: 61 8 8313 6600