Feedlot animal efficiency helps cut beef sector emissions

Dr Stephen Wiedemann presented Carbon Accounting 101

during the Entegra sponsored webinar

Dr Wiedemann took the audience through basic greenhouse gas accounting terminology and calculations, while also outlining the role of feedlots in the beef supply chain’s carbon footprint.

He said the nation’s beef industry methane emissions – measured every five years as part of The Australian Beef Sustainability Framework – had reduced by 1.5 per cent per kilogram of (carbon dioxide equivalent (CO2e)/kg liveweight.

This “steady decline” in emission intensity was something he expected would continue.

“In those national results, all of beef in Australia, the key driving factor has actually been the feedlot industry,” Dr Wiedemann said.

“Because it’s driving higher production, higher beef turnoff from the whole herd for a start – heavier turnoff weights – but also faster growth rates and that means that animals are on Earth for fewer days before slaughter generating methane, but they are turning off as much or more beef. That is a key contribution to the whole industry that the lot feeding sector has had.”

In addition to these mitigating factors, Dr Wiedemann said cattle on a high grain rations emit about half the methane emissions compared to cattle on grass.

This positive message about emissions from the feedlot sector was underpinned by the efficiencies of short-fed export cattle compared with Queensland and NSW grass-fed cattle.

These animals are on feed for less time before slaughter and delivered the same or heavier slaughter weights, according to Dr Wiedemann.

For those lot feeders wanting to examine their own emissions, Dr Wiedemann advised recording the base line emission intensity for their current business and then using something to benchmark against.

Benchmarks he showed the group referred to scope one and two emissions reported relative to liveweight gain in the feedlot.

These scope one and two emissions mostly included methane from the cattle, manure, machinery operation and electricity.

For short-fed domestic heifers 66 days on feed (DOF), short-fed export steers 110 DOF and long-fed export 200 DOF, the emission intensity for scope one and two emissions was 3.3-4kg CO2-e per kilogram of liveweight gained.

Once the entire supply chain was included in this emission intensity benchmarking – which meant adding the impact of grain and beef cattle production and changing the unit of reporting to emission intensity per kilogram of liveweight sold – these numbers went up to 9-11kg CO2-e/kg liveweight sold.

Dr Wiedemann said feeder cattle contributed 70 to 90 per cent of this whole supply chain figure.

To explain total emissions, Dr Wiedemann used the carbon account of a 10,000 head feedlot and broke down the emissions into scope one, two and added scope three – emissions necessary to production but were outside the control of the feedlot- such as grain production.

This data showed that the feedlot’s scope one and two emissions were up to 24,000 tonnes CO2-e of a total 194,343 CO2-e once scope three emissions were factored in.

What can be done to reduce emissions?

Dr Wiedemann said the beef research community started looking at reducing methane emissions before global warming made it a priority as it represented a major energy loss from animals.

He said methane represented 6.5 per cent of the gross energy lost for grass-fed animals and 3-5 per cent for feedlot cattle, although this varied depending on each animal’s diet and its stage in the feedlot.

Feed supplements and management practices have attracted the most interest when it comes to reducing methane emissions.

Dr Wiedemann used the example of altering the volume of dietary oils, which are used extensively in feedlot rations, to deliver a 5-10 per cent reduction in emissions.

Up to 70-90 per cent emissions reductions were possible via novel feed supplements such as Bovaer (3- NOP) and red asparagopsis, with higher emission reduction in high grain/finisher rations compared with lower grain and/or starter rations, he explained.

While there were commercial trials of these novel feed supplements, Dr Wiedemann said supply and cost had been a major limiting factor.

Dr Wiedemann’s ALFA SmartBeef Bites presentation was one of three included in the ALFA SmartBeef Bites Smart Sustainability webinar sponsored by Entegra.