Research continues across a number of subject areas in the race to find ways of reducing methane emission levels within ruminant populations.
Courtesy of his recent Queen’s University Belfast lecture, University of California (UC), Davis academic, Prof. Ermias Kebreab reviewed the latest direction of travel where this work is concerned.
He confirmed that certain seaweeds will generate significant reductions in methane production when used as feed additives.
In practical terms, however, a number of practical challenges quickly emerged. These include the sourcing of sufficient seaweed feed stock to make a meaningful impact at commercial farming levels.
Linked to this is the treatment of the seaweed in ways that would allow its straightforward inclusion in feed rations.
Kebreab said: “It also became evident that adding the required quantities of seaweed can give rise to palatability-related issues.”
According to the UC, Davis academic, bromoform is the active molecule within seaweed that delivers the methane-reducing impact when added to ruminant rations.
“Research projects have looked at the addition of pure bromoform to livestock rations,” he said.
“This work has confirmed that powdered bromoform does not impact significantly on enteric methane production levels.
“However, when the active chemical is made available in the form of an oil-based suspension, significant reductions in methane emission levels will be secured.
“It has also been shown that other organic halogens, including iodoform, can act to reduce enteric methane production activity.”
Reducing methane emissions
There are a number of feed additives groups in addition to seaweeds that have been shown to significantly reduce methane.
These include tannins, fatty acids and bespoke chemistries, such as 3-NOP.
According to Kebraeb, there is some evidence to show that, where dairy is concerned, they will act to reduce methane production throughout an entire lactation.
In addition, this reduction in methane emissions will continue to take effect into future lactations.
Of equal significance is the impact of feed additives when added to the diets of calves and weanlings.
Research indicates that, in this context, the additives may work to permanently alter rumen microbe populations.
Other approaches that can be used to reduce enteric methane production include the development of bespoke breeding programmes, the use of gene-based technologies that can impact directly on rumen microbe populations, and the development of bespoke vaccines.
Professor Kebraeb concluded: “Identifying those microbes within the rumen that specifically capture hydrogen is another area of research that is showing promise.
“Breeding animals that will inherently produce less methane represents a very sustainable way forward.
“However, the drawback here is the significant period of time it will take to secure a meaningful difference when it comes to the actual amounts of methane that animals produce.”
