Better breeders, better gains, lower emissions
Against the often-harsh backdrop of Australian rangelands, red meat production can be challenging. According to a new project, such conditions also create difficulties for producers to reduce their enteric methane emissions, although they are not impossible to overcome.
Research has revealed optimal interventions for rangeland producers to reduce their emissions without compromising profit, productivity or biodiversity habitat.
“Reducing enteric methane is a challenge regardless of whether you’re in the rangelands or elsewhere, because enteric methane can account for 70–80% of direct farm emissions,” University of Tasmania Professor Matt Harrison said.
“In the rangelands, it’s difficult because some of the levers you could pull elsewhere are disabled by lower rainfall, lower pasture production and lower capacity to sequester carbon.”
Keeping profit in mind
Research has revealed optimal interventions for rangeland producers to reduce their emissions without compromising profit, productivity or biodiversity habitat.
“Reducing enteric methane is a challenge regardless of whether you’re in the rangelands or elsewhere, because enteric methane can account for 70–80% of direct farm emissions,” University of Tasmania Professor Matt Harrison said.
“In the rangelands, it’s difficult because some of the levers you could pull elsewhere are disabled by lower rainfall, lower pasture production and lower capacity to sequester carbon.”
Opportunities to reduce emissions
Matt said while soil carbon sequestration in the rangelands is lower than that in higher rainfall zones, enteric methane emissions per hectare in the rangelands are much lower than those in high-rainfall zones. This is because stocking rates in rangelands are typically much lower.
“The scale of rangelands enterprises offers greater opportunity for carbon sequestration and biodiversity habitat improvement in woody vegetation compared with intensive zones, because land area in the rangelands is more abundant, although potential for carbon sequestration via woody vegetation is very much site-specific,” he said.
Better breeders reduce emissions intensity
A significant proportion of the emissions per kilogram of liveweight are attributed to maintaining the breeding herd. The more liveweight produced through successful offspring, the more kilograms to attribute emissions too, reducing the emissions intensity.
“If your calf mortality is high because of poor cow nutrition, focusing on improving breeder nutrition to reduce calf mortality will improve productivity and reduce emissions intensity,” Matt said.
“If you can increase the whole enterprise ratio of growing animals to mature animals, that will also improve your emissions intensity by having less cows in the paddock which aren’t growing. Increasing the proportion of growing animals to adults will further reduce whole farm emissions intensity.
“Improving your emissions intensity is really a co-benefit of improved animal management and improved nutrition,” he said.
Fine-tuning carrying capacity
Productivity can be better sustained by optimising – not necessarily increasing – carrying capacity to your environment.
“Try to calibrate your whole-farm stocking rate to the worst conditions you can expect, within and across years. This is the number of animals you can sustainably carry in the worst conditions.”
Matt said, often those conditions are drought.
“Droughts are common in the rangelands. It’s important to plan for them and learn from those producers who are in highly drought-prone regions.”
According to Matt, in good seasonal conditions, lower stock rates can be compensated for by having fatter animals and better liveweight gain. Lower stocking rates also tend to reduce the need to destock or buy in feed during dry conditions.
“When existing stocking rates are excessive, pastures are often overgrazed, increasing the risk that the most productive and palatable pasture species are lost. This reduces ground cover, increases soil erosion and causes losses of productive pasture species. Together, these factors reduce livestock nutrition to the point where mortality and animal welfare becomes a risk,” Matt said.
“But every environment is different. Optimal stocking rate depends on how long pastures are grazed, soil type and rainfall, which together influence pasture growth and recovery from grazing.”
Every farm is different
Throughout the project, Matt and colleagues have been working with producers across Australia to model the impact of interventions they’re interested in undertaking, including whether it will be environmentally impactful and beneficial to their operation.
For one producer, addressing feral browsers was the answer that unlocked every co-benefit.
“There was an issue with excessive rabbits grazing his pasture, so we modelled the impact of a game-proof fence along a 3km stretch, fencing off his native bushland,” Matt said.
“We found that would improve profit, liveweight gain, pasture growth and soil carbon.
“This improved economic, environmental and agronomic outcomes. That producer has now fenced off the bushland based on these results.
“For some producers, this work is about building an awareness of practices they can implement and what sustainable pathways mean for their operation, whether it’s now or in 10 years.”
It is important to note that impacts of any practice change depend on historical management, climate and context. Because every farm is at a different current state, the relative benefit, or lack thereof, associated with any practice change varies for farm to farm and year to year.
