29 November 2012

Beef cattle could be bred to produce less methane

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Cattle can be bred to emit less methane and reduce the contribution of beef production to climate change, said an Australian researcher who spent two years measuring cattle burps.
Cattle could be bred to produce less methane

Aussie beef cattle could be bred to produce less methane, according to a presentation at the Climate Change Research Strategy for Primary Industries Conference being held in Melbourne. Credit: iStockphoto

MELBOURNE: Cattle can be bred to emit less methane and reduce the contribution of beef production to climate change, said an Australian researcher who spent two years measuring cattle burps.

Worldwide, cattle are a major source of greenhouse gases, belching two gigatonnes each year. Grazing beef cattle are responsible for 6.4% of Australia’s overall greenhouse gas emissions – and methane, the main component of their gas, is 20 times more effective at trapping heat in the atmosphere than carbon dioxide.

Kath Donoghue and her team at the New South Wales Department of Primary Industry measured the emissions of 339 Angus cattle to find that the “lowest-emitting” bulls sired progeny that emitted an average of 24% less methane than the calves born to “highest-emitting” bulls.

“There is a measurable difference… so we know genetics plays a role,” said Donoghue, who presented her results at annual Climate Change Research Strategy for Primary Industries conference in Melbourne.

Capturing cattle burps

Up to 10 cattle were placed in specially designed enclosed chambers for 48 hour periods. The researchers measured the cattle’s overall methane production (in litres per day) and methane yield, a measure of gas produced per feed eaten.

The project was a proof of concept; but, now, to isolate the cattle whose progeny have the lowest methane emissions, Donoghue estimates they’ll need about one thousand more measurements. Once they find the genes associated with the trait of reduced gas, methane emission could be predicted using a single strand of hair from a newborn calf.

This insular research environment is limited, though, and the team also have plans to expand beyond it in three years’ time. Using technology similar to police breathalyzers, they will build a measuring tool that can be used in industry paddocks. The cattle would walk into a tent-like structure with a feeder, be identified via an electronic ear tag, and have its breath tested by a small vacuum-like hose. Measurements would be taken over a six-week period.

What’s puzzling the researchers is how to control for naturally occurring environmental variations of the methane levels. So for now, Donoghue and her colleagues are continuing to use the chambers at their lab in Armidale.

Enticing farmers to use selective breeding processes

Genetic improvement is a known technology. It has a history of being accessible and traits from elite sires can be quickly spread via artificial insemination. Donoghue hopes that “low-methane” will be included in cattle’s estimated breeding values (EBV), the profit indices used to describe the genetic merit of cattle.

Lucinda Corrigan, a farmer from Rennylea Pastoral Company, told COSMOS Online that the farming community would need to have confidence in the research before it would alter its practices: “We want to have faith that it won’t affect the quality of our product.”

But Corrigan agreed that if the research was accepted by the farming community, methane emissions could be added to the current index of breeding traits. The weight of the trait would depend on the accuracy of the research. “It depends how good the science is. If it has good accuracy, we would rate it.” She explains that cattle would need to be in a chamber for 70 days for the measurements to be considered accurate.

There are some economic incentives for the farming community to add low emissions to its list of breeding traits. If the Australian Government accepts the research, even a 1% reduction in the cattle-produced greenhouse gases could be worth A$8.3 million under the federal Carbon Farming Initiative (CFI).

But is this enough? Richard Eckard of the Primary Industries Climate Challenge Centre said that, even with the CFI offset, adoption will be limited. He cautioned that breeding for reduced methanogenesis is “not a high priority” for the industry in comparison to traits like fertility and size. And he said there is little evidence that animals with desirable genes—such as reduced feed intake—have lower methane emissions.

At the end of the day, it’s the price of carbon

Audience member Nick Edwards summed up the farmers’ viewpoint: “There’s not much point in focusing on other stuff if it’s not going to improve productivity.”

Donoghue agreed: “Even if farmers were able to choose a bull that was low-methane, I still don’t think they would go out and specifically target low-methane unless there’s a big financial incentive.” She said the next step is to link low-methane genes with other genes to breed cattle that produce less methane and have desirable fertility, carcase and meat quality traits. So far, her team has found virtually no negative relationship between methane emissions and traits like weight, but they will need about 3,000 records to prove this at the genotype level.

“Our early indications are that we can improve methane emissions without impacting profit,” Donoghue said. But she also said that a lot depends on government policy, “We can provide all the tools we like, but the policy framework is not set by us. At the end of the day, I think it’s the price of carbon.”

In comparison to other methane-reduction strategies (such as altering cattle feed), genetic technology has the advantage of being wide-reaching while making permanent, cumulative changes. “It’s a one-generation intervention that leads to on-going reductions,” said Eckard

Donoghue predicted that, within about a decade, Australian cattle producers could be purchasing bulls that breed generations of greenhouse-friendly cows.

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