Caution needed in methane reduction measurement
By David Messina*
As the livestock industry becomes increasingly sophisticated around its role in contributing to net zero goals, so too should the measures it adopts to assess the effectiveness of methane inhibitors in cattle.
Just as chasing high weaning weights can have a negative impact on calving ease (by virtue of associated higher birth weights), a cattle industry looking to reduce its methane emissions needs to adopt measurements that provide a net benefit.
To date methane reduction has been the simplest and therefore most readily and widely adopted measure. It compares a control group with a test group and measures any comparative reduction in methane production.
If cattle are producing less methane, whether it’s 10% or 90%, then that’s great for the environment.
However, crudely, the best way to stop cattle emitting methane is to stop them eating. If that occurs there will then be no fermentation in the rumen, no methane production and no greenhouse gas emitting burps. Simple. The downside, however, is that the growth rates of your cattle suffer.
Unfortunately, the simple measure of methane reduction doesn’t take this factor into account. As a result, methane production/reduction figures can be driven in part or in total by reduced feed consumption rather than solely by the methane inhibitor.
And if that occurs, you need more cattle to produce the same amount of meat or milk, and the methane reduction previously achieved is neutralized or marginalized.
Methane yield is a more useful measurement because it normalises the feed intake issue.
It is a measure of methane production per unit feed consumed (CH4 grams per day / kg dry matter intake).
Given growth rates are correlated to feed intake there is a logical assumption that if feed intake remains the same or improves, and methane production reduces, then the methane inhibitor is doing its job without negatively impacting performance.
However, the beef and dairy industries look beyond net feed intake to more sophisticated Feed Conversion Ratios or feed efficiency measures because they take into account the performance of the animal versus simply relying on the feed it consumes to assess performance.
Methane intensity does the same, measuring methane reduction against growth rates (CH4 grams per day / avg daily weight gain).
This is a superior measurement as the more kilograms of beef or milk that the livestock can produce, while at the same reducing methane production, the better the environmental outcomes will be.
Logically reducing methane intensity should be achievable. Considerable energy is ‘lost’ during the rumination process when starches are converted to methane. If that fermentation converts the starches into an alternative form of energy which is available to and usable by the animal instead of being burped, it can then be converted into extra meat or milk.
This is the holy grail of methane measurement because if proponents can demonstrate that there is a productivity gain at the same time as a reduction in methane emitted, then everyone wins and adoption will be greater.
Practically, it is achievable too. To date Rumin8 has achieved up to 9 per cent productivity gains in its animal trials, while achieving 50-90% reductions in methane intensity in the feedlot and 24-50% reductions in the paddock.
So by achieving reductions in methane intensity, we can reduce the environmental footprint of the global cattle herd whilst improving global food security.
* David Messina is a Co-founder and CEO of Rumin8, a climate technology company using a pharmaceutical approach to reproduce and stabilise nature’s solutions to make affordable feed supplements that reduce methane emissions from livestock.
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