Life’s a gas for uni trial cattle

Fossil fuels and coal-fired energy stations are enemy number-one for many people, but less is said about another big contributor - agriculture. It is Australia's second-biggest emitter of greenhouse gases and produces about 20 per cent of the nation's emissions.

University of Adelaide Animal Science project manager Melissa Ann Rebbeck says 70pc of that is produced by cattle in the form of methane.

She is now managing a project to produce a specially made pellet that will reduce methane emissions from livestock and increase their weight gain and performance.

"We're looking at using different feed sources that are cheap and readily available over the feed-gap period to combine them and produce a methane-reducing pellet that is also performance enhancing," she said.

"It's made from cheap waste products basically, such as grape marc, lucerne offal, canola meal and barley.

"It's a combination of those products, which we can almost get for free, and if they are combined in the right way, they can actually enhance the weight gain and performance of animals."

Ms Rebbeck says that many farmers carry their pregnant cows over summer, a time when there is usually no available pasture and a high feed requirement.

Methane measurements will be predominantly undertaken with pregnant cattle, which have larger feed requirements because of a growing foetus and higher methane emissions

"Their energy demand is a lot higher and these methane-reducing pellets will aim at reducing methane whilst enhancing performance," Ms Rebbeck said.

She originally started the project with SARDI but has now moved to the University of Adelaide where she is undertaking an initial trial at the Roseworthy campus with supervising Prof Phillip Hynd and two post-doctorate researchers Dr Mariana Caeteano and Michael Wilkes.

Integral to the project's continued funding from the Federal Department of Agriculture Fisheries & Forestry is a need to measure methane output. To do this, the group has commissioned C-Lock Inc, Rapid City, South Dakota, United States, to install two methane and carbon dioxide measurement systems called GreenFeed units at the university's Roseworthy campus.

C-Lock director of engineering Scott Zimmerman saYS the machines dispense a small amount of feed, encouraging the animals to put their mouth and muzzle into a hood where the machine sucks out the gas they emit while burping, to measure air flow and gas concentrations.

"The purpose is to get the animal to hold still for roughly five minutes, and while the animals are eating out of the feeder, the system will measure the methane they're emitting," Mr Zimmerman said.

"The methane and CO2 are bi-products of metabolism from the animals.

"The more an animal eats and the more efficient and inefficient they are, the more or less methane levels they emit."

He says the GreenFeed units are being used on every continent except Africa and Antarctica.

"We have several clients using them to study different ways to reduce emissions," he said.

"We also have several clients using them for efficiency studies for different animals, while other clients use them to look at genetic traits in the gas emissions."

Ms Rebbeck says that the university's two units - costing $50,000 each - are the only two in SA and the trial is one of only two projects in Australia using the machines.

"Methane has a shorter lifespan than gases like carbon dioxide, so technically, if you reduce methane in the atmosphere, it can have a bigger impact on global warming," she said.

"This research will be used worldwide."

Trials will be undertaken with up to six farmers across South Australia.