Using grape marc as a feed additive in commercial settings
Grape marc has been identified as a potential feed additive for the livestock industry able to improve productivity and reduce methane emissions. In order for grape marc to be widely used in the livestock industry, some practical barriers regarding storage and distribution need to be overcome. This project commenced in September 2013, building on the work investigating grape marc tannin described above. Funded through the DA ‘Action on the Ground’ program, this project aims to address the practicalities of feeding grape marc to livestock. Specific areas of focus are: preventing mould formation during storage and feed-out; developing effective large-scale storage solutions that preserve both tannin and nutritional content for year-round feeding; and integrating storage solutions and mould inhibition into realistic on-farm practices that can be applied and refined during feeding trials.
Use as a feed additive
A number of different mechanisms for large-scale storage of grape marc were assessed for their ability to maintain the nutritional value and tannin concentration of marc over an extended time frame, while minimising mould formation. All of the methods trialled were found to be effective, which means that there is flexibility for users to choose the method that best suits their farming system in terms of economics, ease of use and requirements for specialised machinery.
A pilot trial using grape marc as an additive in a feedlot system was successful, prompting the initiation of an extensive 100-day feeding trial. Two unique grape marc parcels have been stored at Tullimba Feedlot (University of New England) using grain bags, and will be fed to beef cattle alongside a control diet. The primary objectives are to assess the daily methane emissions, feed intake and feed use efficiency (intake against weight gain).