Case study - What goes in must come out

​Case study – Department of Agriculture, Fisheries and Forestry, Australia’s Farming Future: Climate Change Research Program (CCRP)

What goes in must come out

Drive across the countryside and you will see thousands of sheep and cattle grazing quite happily on grass and pasture planted by Australian producers.

Scientists, received funding through the Australian Government’s $46.2 million Climate Change Research Program to investigate if plants that have been in Australia for millions of years could be integral to reducing methane emissions.

Associate Professor Phil Vercoe, from the University of Western Australia, has worked on forage trials to reduce methane emissions and comments that producers don’t traditionally see Australian native plants as valuable livestock fodder.

“Often this is because of their low biomass productivity and nutritional value when compared with improved pastures or crops, “ he said.

“But native plants have developed into quite robust plants. They have adapted to things like drought, soil fertility and pest pressure and simply get on with the job,” Associate Professor Phil Vercoe said.

The unique project was just one of 39 research projects coordinated by Meat & Livestock Australia through the Reducing Emissions from Livestock Research Program (RELRP).

National program co-ordinator, Dr Julian Hill, said the RELRP has delivered new knowledge in five main areas: genetics and animal selection, nutrition, rumen microbiology, farming systems and waste management.

“Scientists have developed a range of nutritional and management strategies that can be adopted by the industry to reduce the overall production of methane in the rumen,” Dr Hill said.

The Western Australian forages project investigated the role that diet plays in methane generation.

“Sheep and cattle eat large quantities of fibre every day.  This fibre is broken down in the rumen by microbes, which in turn provides the energy for the animal,” Associate Professor Vercoe said.

“Methane is simply a byproduct of the food stuff in the rumen.”

Associate Professor Vercoe said although there are some synthetic antimicrobials that can be fed to animals to control methane, there is increasing consumer demand to move away from synthetic additives and plants that reduce or inhibit rumen methanogenesis could provide a ‘natural’ alternative.

“It’s our belief that native plants can be fundamental in helping the livestock sector reduce greenhouse gas emissions and mitigate future climate change,” he said.

“We have investigated the type of compounds that may be responsible for the antimethanogenic effects of the plants and how they affect the microbes in the rumen.”

The forages project – conducted at a number of Western Australian locations including UWA’s Future Farm ‘Ridgefield’ site – tested more than 150 novel and more commonly used fodder plants that could be used in wider livestock production zones in Australia. At least six of the plants showed real promise in reducing methane production.

“Of those plants, one in particular, Eremophila glabra (E.glabra), a shrub that tolerates harsh growing conditions, reduced methane production by over 50 per cent when tested in the lab as the sole substrate in the test,” Associate Professor Vercoe said.

Associate Professor Vercoe added that the 50 per cent reductions have only been demonstrated in the lab, but his group has evidence that sheep fed E.glabra at 15 per cent of their diet produce 10 per cent less methane without reducing their productivity.

E.glabra does not produce a lot of biomass, so producers are not going to feed their stock an entire diet f this – the fact that methane production is reduced when the sheep consume it at only 15 per cent of their diet is also encouraging,” Associate Professor Vercoe said.

Greg and Robyn Richards at Dangin, WA, were involved with an on-farm forage trial.

The trial was a comparative study of productivity (weight gain) and methane production between sheep grazing typical self-sown pasture while supplemented with barley and sheep grazing a system that included a mixture of shrubs (inc. E.glabra and Rhagodia preissii – another shrub of interest) and a standing barley crop.

Greg said the forages trial were an interesting one to participate in.

“We traditionally hand feed sheep from January to May and when there is no new seasons pasture available and if we can have a fodder shrub to substitute hand feeding at this time, that’s a great outcome.“

“If science can show that native perennial shrubs can reduce greenhouse gas emissions at the same time as helping maintain profitable grazing systems, then it’s something worth looking into.  That’s one of the key reasons for being involved in these trials,” he said.

In addition to methane reduction, Associate Professor Vercoe said E.glabra also showed to have other production benefits.

“It seems it can also reduce the risk of acidosis or bloat when you feed wheat to sheep and has the potential to reduce bacterial infections in the gut and reduce worm burdens,” he said.

“So this plant could potentially be incredibly valuable for sheep producers on a number of fronts.”

“If we can find native plants that make suitable livestock fodder, there may not only be an environmental benefit but a production advantages in terms of feed efficiency and animal growth as well,” he said.