CAN COW BURPS BE CLEANER THANKS TO SEAWEED?
Changing how cows burp could dramatically reduce greenhouse gas emissions, according to Rob Kinley, a Dalhousie-educated researcher working in Australia. He found that feeding artificial cow stomachs seaweed reduces the amount of methane they produce by u
Q How much methane do cows produce, and how does that contribute to climate change?
A On average, one cow produces about as much greenhouse gas as one car. Cows produce methane at a rate of about 300 grams a day for dairy cows, 150 grams for beef cows. It varies with their diet.
Q What is it about methane that’s problematic?
A It’s a greenhouse gas that’s about 28 times more potent in terms of global warming potential than carbon dioxide.
Q Before testing the seaweed on live cows, you built a fake cow stomach and tested it in a lab. How do you build a fake cow stomach?
A The cow’s first stomach, where the gas is digested, is more like a fermentation tank than a stomach. So if you supply that system with all the things that a cow would give it, say: temperature maintenance, ph maintenance, a steady flow of nutrients and waste removal, then you can duplicate that system in the laboratory. Then you can play with it by feeding it anything you want to and you can do that ethically.
Q Do they actually look like a stomach?
A No, they’re glass. There are a number of forms of them. The ones I was working with in Nova Scotia are double-wall glass. The temperature is maintained by running the precise degree of water between the walls and the inside of the tank where the fermentation is going on. So they look like suspended bottles.
Q You tested 20 types of seaweed and found that a red seaweed off the coast of Queensland, Australia, produced the best results. What’s special about this seaweed? A That particular seaweed has one chemical that it uses as a natural defence against predation in the ocean. We’ve discovered that it works quite well in the process of methane production.
Q Do cows like eating it?
A Well, they don’t even know that they’re eating it. You put it in pellet form or mix it with molasses and they gobble that down. We haven’t actually fed it to cows at any level yet. We’ve fed it to sheep. Sheep are smaller and require a lot less feed and are easier to manage. We are going to feed cattle very soon.
Q When you gave it to sheep you saw an 85 per cent reduction in methane. Are you expecting a similar result?
A We are. The seaweed that we’re going to be giving the cows is actually of a much better quality. When we did the sheep study, we took the seaweed that we had at the time. It had been sitting around for a while, so it had lost some of its potency, but it still worked really well at low levels. I’m expecting even better results with the cattle.
Q What part of the cow contributes most of the methane output?
A It’s the burping, at about 90 plus per cent. Farting accounts for the other 10 per cent or so.
Q How much seaweed would you need for, say, all the cows in Australia?
A Ten per cent of the beef feedlot and dairy industry in Australia would require about 30,000 tonnes per year. So if we were to move into the American market, then you can multiply that by 10. If we had 100 per cent uptake globally, we would need one million tonnes. That level of seaweed is already being produced for other purposes.