Recently, I made a somewhat flippant comment that a “flatulence-control program for bovines” would be more effective in reducing greenhouse gas emissions than switching to environmentally-friendly light bulbs, as proposed by Malcolm Turnbull.

That’s because in Australia, livestock produces 65.2 million tonnes of emissions each year; Turnbull’s light bulb plan, in the initial phases, would save a comparatively small 800,000 tonnes annually. A dairy cow can produce up to 165kg of methane a year, enough to power a 6-cylinder LPG car for up to 1,480km.*

So I’ve turned my attention to cows. Crucially, it turns out that 95% of methane produced by cows is actually breathed/belched out. Only 5% comes out the other end. This is new news to me, but old news to many.

Australian scientists are already hard at work on the methane issue. Through the University of Melbourne and the Victorian Department of Primary Industries, Dr Richard Eckard and his team — in a joint project with Canadians and New Zealanders — have developed large animal calorimetry chambers (pictured below) to help measure methane going in and out of dairy cows. None too dignified but as Eckard says, it’s the “only way to get it right”.

PICTURE: A dairy cow in the methane chambers at Ellinbank, fitted with faeces collection bag.

Methane is produced when methanogens, microbial bugs present in animals’ stomachs, interact with food. The process, while it impacts the environment, has no positive benefit on digestion or cow. In fact, it consumes vital energy that in dairy cows could be better invested in producing milk — if you stopped all methanogens from attacking carbohydrates, you could get about an extra 4.5L of milk per day per animal. This is the “top end” solution, says Eckard. “It may be hard to achieve in practice, but gives a target to aim for.”

For now, the New Zealanders and Australians are using a similar approach to the problem but coming at it from different — yet complementary — ends. Kiwi scientists have been growing forages that contain methane-reducing compounds. In Australia, they’re looking at dietary supplements in a capsule instead. And it’s all very holistic, using tannin from Australia’s black wattle.

We’ve been able to reduce methane by 30% but with a “slightly reduced milk production”, says Eckard. We need to get to the stage where it’s advantageous for farmers, or “at the very least, break even”. In the meantime, simple things like reducing the number of “unproductive cows” and extending the length of time that remaining cows lactate “can both increase the bottom line and reduce methane”.  

*According to calculations based on Dr Eckard’s research. For more information about the project, click here.