SPECIAL REPORT | EMISSIONS
don’t have too, to see what works.” As well, MPI is funding an offpaddock wintering facility for the hub to be built this autumn. DairyNZ senior scientist Dawn Dalley said during a trial in the winter, pugging depth (it must be less than 20cm under the NPS) was determined by pushing a plastic ruler into the soil. “When it met resistance, that’s what we decided was the pugging depth. What the government comes up with is anyone’s guess.” The trial, called “How Much Mud is Too Much Mud”, looked at whether cows were achieving the minimum standard of eight hours lying time per day while on winter crop paddocks. Behavioural monitoring equipment (CowManager tags and HOBO accelerometers) were fitted to 30 cows in four mobs on kale and fodder beet for the five-week trial. Although the data, including rainfall, are still to be crunched, DairyNZ animal care team leader Helen Thoday said it was hoped visuals from it of what was good or bad practice would soon be available to farmers. “Without a doubt, animals which have sufficient lying time do better.” In answer to a question of whether public perception was a valid measure, she said apart from dividing media articles into negative or positive, it was difficult to tell what public perception was. “We have asked the question whether it reduces our market access and there is nothing certain there either. “But public perception should only be one measure. It is really how the animal genuinely feels and that can also be hard to tell, which is why we’re doing the trial work.” Farm manager Charlie McGregor was an instant fan of the CowManager tags used during the trial. “We got an alert from the system that one of the cows was sick and it showed it wasn’t ruminating, and we were able to treat it. Otherwise we wouldn’t have known.”
Native seaweed could reduce GHG emissions
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Words by: Richard Bentley
New Zealand native red seaweed, if used in stockfeeds, has the potential to reduce methane emissions from ruminants, and the Cawthron Institute in Nelson is investigating the best ways of producing it in huge quantities. Asparagopsis armata grows abundantly throughout NZ waters, and early studies suggest that as little as 2% of dried algae added to stockfeeds could reduce ruminant methane emissions by up to 80%. This is important to NZ’s efforts to combat climate change, particularly because our livestock methane output has increased about 10% since 1990. The potential for Asparagopsis is significant if only it can be grown on a scale large enough to feed all NZ’s dairy herds. As yet not a lot is known about its culture and growth habits. To lay the foundations for a future industry, scientists need to determine precisely how it reproduces and what conditions
Samples of the red seaweed in the laboratory.
Dairy Exporter | www.nzfarmlife.co.nz | November 2020
are best for its growth. For example, will it thrive only in warmer waters or can it be grown anywhere? Should plants Dr Johan Svenson. be attached to something or floating? Are there fertilisers that will make it grow more rapidly? Are there some strains that have higher content of active ingredients than others? Which part of its lifecycle is most suited to different production systems (e.g. land-based, near-shore, etc.) and which is best to produce the active ingredient? These are questions scientists at the Cawthron Institute are working on. The Institute has a long history in algal research (seaweed is a type of macroalgae) and the leader of algal research, Dr Johan Svenson, says that they are now studying its life cycle in detail. “Even though it is a seaweed its reproduction is quite complex so we are trying to understand how to get it to reproduce in a controlled fashion on a small scale so that we can optimise the growing conditions on a larger scale,” he says. “Asparagopsis is a carrier of a bioactive component so we want to know when in the life cycle that is being produced and then grow it in a way that we can control the amounts of this compound.”
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