In an interview with FeedNavigator this morning, Melissa Rebbeck, senior researcher at the University’s School of Animal and Veterinary Sciences, said the pellet, which has already been tested in three farm trials in Southern Australia, shows promise in reducing methane emissions whilst enhancing performance and lowering feed costs.
“This is an ‘action on the ground project’, funded by the Federal Government Department of Agriculture under the Carbon Farming Initiative. It is associated with research but also involves farmers at the onset in order to produce something that they will utilise in what we call the feed gap period. It needs to be commercially viable and aims to increase performance and reduce methane,” explained Rebbeck.
The researchers’ aim is to complete 12 ‘case studies’ – in which farmers incorporate specially-formulated methane-reducing supplements into their animals’ diets for up to three months at a time – by the end of 2016. ‘Green Feed’ units from the US are being deployed to measure methane emissions from the animals.
It’s in the tannins
It is the tannins in the key ingredient - grape marc - that may be responsible for the methane reduction, according to Rebbeck: “Grape marc contains a high level of tannins which may inhibit methane production.”
Grape marc is a by-product of the wine-making process, and, with Southern Australia home to a sizeable wine industry, over 200,000 tons of grape marc are produced there annually. It consists of the stems, seeds and other waste products left over once the grapes are crushed, and has a metabolisable energy content of 9-13 Mega Joules/kg of dry matter, and a crude protein content of 9-12% of dry matter.
This makes grape marc a potentially-valuable feed supplement to fill the feed ‘gap’ in southern Australia between November and March each year. Being a Mediterranean environment, with little rain over this period, pasture production and feed quality are low over this period.
Whilst performance improvements and methane reduction may be two reasons for incorporating the grape marc into animal diets, inclusion may also be justified on the basis of cost savings alone. “Producers are already feeding it to their cattle and sheep so we thought there was a need to test it,” said Rebbeck.
The other main ingredient in the supplement is a byproduct of lucerne, which is grown as a perennial pasture plant for grazing. The supplement uses the by-product or ‘offal’ of the feed, made up of stalk, leaves and stems.
This byproduct has a metabolisable energy content of 9-10MJ/kg dry matter and a crude protein content of about 27% of dry matter. “There’s a lot of work going on around the world on the methane-reducing potential of lucerne. It provides even more protein than grape marc, but is not as widely-available,” explained Rebbeck.
The work being done by the University of Adelaide could also be applied in other parts of the world with similar ‘Mediterranean’ climates. “There’s no reason why this couldn’t be done in other ‘Mediterranean’ regions – if they are not doing it already,” said Rebbeck.