Australian environmental researchers have discovered that kangaroos may be useful for more than just tourist photos and ill-advised man vs. marsupial boxing matches.
They are hoping the bouncy creatures may also help reduce the amount of methane produced by the country’s cattle and sheep.
The research is part of an initiative by the Queensland state government to cut down on methane emissions from cattle and sheep, which account for 14 percent of Australia’s greenhouse gases.
According to the Canadian Cattlemen’s Association, cattle and sheep account for three percent of Canada’s methane emissions.
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“Currently one of the byproducts of anaerobic fermentation in the rumen is hydrogen gas, and there’s a group of microbes called methanogens … and they use the hydrogen and carbon dioxide and they convert it into a gas called methane,” said Diane Ouwerkerk, a senior biologist with the Queensland government.
The methane produced by these microbes is then released into the rumen and expelled when a cow or sheep belches.
Instead of a rumen, kangaroos have an elongated stomach, the front portion of which is known as the fore stomach. And instead of methanogens, kangaroos have microbes known as reductive acetogens in their stomachs.
Though reductive acetogens also exist in sheep and cattle, they are on the losing end of a competition with the methanogens, while the opposite is true in kangaroos.
“The kangaroo has a very similar process to the cattle in the way it processes grass and all this, but they don’t produce methane, or they produce very small amounts of methane, mostly from hindgut,” Ouwerkerk said.
A sheep’s rumen will produce 40 times more methane than the hindgut of a kangaroo.
According to Athol Klieve, who heads the research project, acetate is a major energy molecule that sheep and cattle use for growth. While acetate occurs naturally in the rumen, it isn’t created by reductive acetogens.
“All that we would be really doing is adding to a pool of this energy material that they already have,” Klieve said.
“It’s basically been calculated that if you could change all of the methane production (in ruminants) to reductive acetogenesis, you’d actually get between four and 15 percent more energy out of the animal, depending on the diet. You could feed them less, or you could get more productivity for the same amount of feed.”
While this may sound promising, the project is still in its early stages. Klieve and Ouwerkerk know why kangaroos don’t produce methane, but they’re still not sure why there’s a difference between the two digestive systems.
“We’re not quite that close at the moment,” Klieve said.
“What we really want to do is work out why, in the kangaroos, this process of reductive acetogenesis out-competes methanogenesis, and how it’s able to do that.”
Though the research is being done in Australia, it could have wider reaching implications.
“If it works in our cattle, I can’t see why it shouldn’t work in Canadian cattle,” Klieve said.
Researchers have managed to isolate bacteria that are involved in the process and their main goal now is to figure out how these bacteria relate to other bacteria, the animal they live in and the feed that the animal eats.
“At the moment, it’s going to be about probably another three years before we really have worked out what’s going on in the kangaroo, and that could be being pretty optimistic as well.”
Klieve hopes that eventually the research will reveal a way to move the microbes and the process from kangaroos to cattle.
Anyone hoping for a genetic experiment resulting in a half-cow half-kangaroo hybrid, however, is going to be sorely disappointed. Instead, the team is planning on using more traditional methods.
“Eventually the long-term idea is to have it as a probiotic drench,” Ouwerkerk said.
“You wouldn’t see cows jumping around like kangaroos … but you’d get more cow poo per blade of grass, and you wouldn’t get the greenhouse gas.”
