'Cleaner, Greener' Cows: how is seaweed helping in the fight against climate change?

Developing “cleaner, greener” cows is something animal scientists and dairy producers have been working on for many years in an attempt to fight the effects of climate change.

In the US, dairy herds now produce more than double the milk than those of yesteryear, with 60 percent less cows. By improving milk efficiency they have been able to half the enteric methane emissions per unit of milk produced, according to researchers at Pen State’s College of Agricultural Sciences.

However, greenhouse gas byproducts, such as methane and nitrous oxide, remain a big problem and these coupled with new targets and regulations have led science towards finding new and innovate ways to solve the issue.

Back in 2015, a team of Australian researchers began investigating the merits of adding seaweed to cattle feed and soon discovered that even small doses could reduce the amount of methane produced by up to 99 percent.

Both scientists from the University of California and the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia discovered that a compound found in a red seaweed almost entirely eliminated methane in cow gut microbes by disrupting enzymes.

Now, one Tasmanian start-up in Australia is taking the story in the country a step further in a new partnership with Fonterra as it attempts to reduce the methane produced by the country’s livestock which currently accounts for 10% of total greenhouse emissions.

For companies such as Fonterra long-term sustainability issues are front of mind and reducing methane emissions has become a priority in helping to do so. Initially trials will focus on one farm in Tasmania before moving to additional farms where tests will continue to see if results achieves can be replicated in dairy herds on a bigger scale. 

As Fonterra's sustainability manager, Jack Holden, told ABC: “The first stage of the trial here is to really just test some of the barriers around commercial viability, operational common sense for farmers, and food safety tests. The end point here is that this is adopted by every farmer.” 

Trials will also monitor milk production and quality, with the focus being on making farmers more profitable as a result. 

However, although other scientific dairy research into Asparagopsis taxiformis suggests significant reductions in methane emissions from livestock where cattle feed has been supplemented with seaweed, researchers argue that the scale of production required to make never it a viable option in the battle against climate change. That's because figures put the number of cattle head in the world at the 1.5bn mark, with 94 million of these being based in the US. 

According to Alexander Hristov, distinguished professor of dairy nutrition at Pennsylvania State University, that’s a problem. 

”To be used as a feed additive on a large scale, the seaweed would have to be cultivated in aquaculture operations, he says. "Harvesting wild seaweed is not an option because soon we would deplete the oceans and cause an ecological problem."

Other questions surround the effectiveness of Asparagopsis as a long term disruptor of microbes in beef and dairy cows, even if short-term studies have proved promising. 

When fed at up to 0.5 percent of feed dry-matter intake results shows no effect on feed intake or milk yield, but at 0.75 percent of the diet, feed intake was down, perhaps suggesting that cows themselves could be the ones to put the brakes on things.

Further reading: Inclusion of Asparagopsis armata in lactating dairy cows’ diet reduces enteric methane emission by over 50 percent.