Seaweed for cows to combat global warming

Dr Rob Kinley with freeze dried Asparagopsis. Photo / Supplied.

New research into seaweed's potential to reduce methane emissions.

A new, all-natural feed ingredient could be a breakthrough in reducing methane emissions from Kiwi cows, helping New Zealand dairy farmers play their part in combating global warming.

First, however, scientists and farmers need to find a way to incorporate it into pasture-based farming practices.

DairyNZ is bringing its expertise to research into the seaweed-based product which studies have shown drastically reduces the amount of methane produced in the digestive systems of cows and other ruminants.

The research is built on the discovery that compounds found in seaweed from the genus Asparagopsis act on the digestive systems of cattle and sheep to reduce the amount of methane they produce, preventing it from being expelled into the atmosphere.

Scientists have found that many seaweeds have a beneficial effect on methane production in animals, but Asparagopsis is the star performer. Research is concentrating on two species, one native to tropical waters and one from more temperate seas, including around New Zealand, which can be converted into a nutritional ingredient of animal feed.

DairyNZ scientist Elena Minnee says reducing greenhouse gas emissions is one of the industry group's key research priorities and it has been looking into a range of options such as breeding lower-emitting animals, vaccines and inhibitors, as well as feed options.

"We've been interested in compounds that reduce methane emissions from animals for a while, and have been aware of what's happening overseas," she says. "Asparagopsis came up on our radar – reporting some really significant results – and we're interested to see if we can incorporate that technology into our farming systems.

So far, overseas research has been based on animals on a TMR (total mixed ration) or conserved feed diet, such as silage: "In a TMR system, it's easy to manage – you put it in the food the animals eat. That's how it needs to be done, the compound needs to be present every day. Once they stop eating it, they stop producing methane at that reduced rate.

Fresh Asparagopsis. Photo / Supplied.

"Our systems are a bit more challenging as we graze our animals outside, and you can't just spread it on the ground and have them eat it. We're working with [FutureFeed] to see what other ways we could offer it to animals and how effective it would be."

Eve Faulkner of FutureFeed* says the methane-reducing powers of seaweed were first recognised when a farmer on Prince Edward Island, in eastern Canada, started feeding his herd seaweed off the beach to provide extra vitamins and minerals to their diet. The cows appeared to be growing faster and, when researchers looked into it, they discovered the seaweed-boosted diet reduced the bovines' methane output by around 20 per cent.

This sent agricultural scientist Dr Rob Kinley on a worldwide search for other varieties of seaweed which might produce an even better result, striking gold when he investigated Asparagopsis.

"In the laboratory, it was a bit of a shocker when I first found it because I thought the instruments weren't working properly; I couldn't find methane at all. It was reducing methane below the detection limits of the instruments we were using. I had never seen that before," he said in a 2016 interview.

Since then, FutureFeed's research has shown that even low levels of the seaweed (less than 1 per cent of feed intake) can dramatically reduce methane emissions. Recent feedlot trials have shown an over 95 per cent methane reduction with just 0.2 per cent of seaweed supplement in the feed ration.

Bioactive compounds in the seaweed act on the cows' digestive system to almost entirely block production of methane. The main one, bromoform, prevents methane release through reaction with vitamin B12 in the cows' first, grass-fermenting stomachs.

For anyone concerned that feeding cows seaweed might result in salty-tasting milk, Minnee says one of DairyNZ's biggest drivers is to ensure any technology or compound offered to animals here does not have a negative effect on product quality. Local research will look at milk composition as well as how the ingredient might affect animal productivity and health.

Freeze Dried Asparagopsis. Photo / Supplied.

"At FutureFeed, the science is the backbone of creating and supporting solutions. Before we go to market with any application, we ensure proven science provides confidence to the market in its safety and effectiveness," says Faulkner.

"We're excited to be involved in the research and about what that could mean in reducing New Zealand's emissions," Minnee says. "It might not be something every farmer chooses to use but we are looking at a range of tools that suit our farming systems and the way we farm – and this could be one of them."

Feed additives are just one of a wide range of options the dairy sector is pursuing to identify the best tools to reduce farm emissions. DairyNZ invests in multiple research programmes into farm system options including vaccines, inhibitors, breeding and forages.

*Following encouraging results overseas, an industry team is joining research into the seaweed-based product. DairyNZ scientists, along with AgResearch, are working with Australian organisation FutureFeed. The latter is responsible for the commercialisation of research done by a range of Australian institutes.