CQU researchers working to reduce methane emissions through water soluble supplementation

But have you ever wondered how emissions were measured in cattle?

Even though there has been some contention about whether the targets will be met, Meat & Livestock Australia has committed to achieving carbon neutrality in the red meat industry by 2030 through research and development.

One of its goals was a 50 per cent reduction in enteric methane emissions in 5 per cent of the nation's herd and flock.

CQUniversity opened the door to some of the research being conducted in the Australian context on methane reduction in cattle at a field day at Belmont Research Station near Rockhampton recently.

The uni-led research is being conducted in conjunction with DITagTech and MLA, and looks at water soluble supplementation to reduce methane emissions.

Rockhampton based senior CQU researcher Dr. Diogo Costa, who grew up producing cattle in Brazil, said while he understood methane discussions that posed producers as the "bad guys" were unhelpful, the discussion was important as agriculture contributed to around 15 per cent of greenhouse gas emissions in Australia.

"This methane that cattle release after digestion is pretty strong at holding the heat, so it's 28 times higher than CO2, hence why there's a lot of talk behind it," he said.

He acknowledged methane from livestock could not be compared with gases produced by other industries as it was a recycled and formed part of a natural cycle. He said herd numbers had also decreased as livestock production had become more efficient over the last 40 years.

It was still early days, but Dr. Costa was working with around 36 water soluble and stable compounds to test their potential in methane reduction. These compounds would soon be put to the test and be measured.

In Australia there exist three main methods for measuring methane - each with benefits and limitations.

The SF6 method uses a physical harness with a soft backpack strapped onto the animal's body. The backpack holds vacuum sealed canisters connected to a tube that sits near the animal's nostrils and releases the inert (generally non-reactive) gas SF6.

Methane and SF6 gasses are collected into the canisters over 24 hours before being analysed. The ratio of methane to SF6 in the eructated gases can be used to estimate daily methane emissions.

Dr. Costa said researchers from both CQU and the University of Queensland had been using this technique and sending samples to the Brazilian Agricultural Research Corporation to validate their practices as the country had been using the technique for much longer.

He said Agriculture Victoria had also been using the system for a number of years and estimated as the demand for methane evaluation continued to rise, the method would grow in popularity Australia due to higher accessibility than some of the other methods for methane collection.

Dr. Costa said one of the limitations of the SF6 method was that it was incredibly labour intensive, which is why he thought Australia had favoured other techniques.

"You have a whole training period for the animals to get adjusted to the halter and everything and you have to have multiple days of collection because one day could be too hot and the animal doesn't eat much," he said.

"You want to have a good representation so the goal is to get at least five days of good collection, we usually aim for six or seven days."

The greenfeed unit uses an attractant, usually in the form of a pellet, to bring the animal close to the unit. While the animal eats it produces methane which is sucked back into the unit and a sample is collected.

Dr. Costa said the greenfeed unit would also likely grow in popularity for use in Australia, but were fairly expensive and could retail for over $100,000 per unit.

He said limitations of the unit came from the fact collections were limited to when the animal came to eat and also that the pellet changed the animal's diet and could interfere with the diet trying to be tested.

"It is not doing collections throughout the whole 24 hour period, you need to estimate what would be released on a daily basis, therefore you need a lot of collections," he said.

The methane chamber method has been labelled the 'gold standard' by researchers as an animal is confined in a contained room and 100 per cent of the gases are collected, meaning measurements would be the most precise.

Dr. Costa estimated the cost of the chamber to be over six figures and said the high cost was probably the biggest impact on its use.

He also said one of the limitations was that the animal's normal routine was affected and animal behaviour could be compromised, meaning data could be skewed.