Newswise — Around 33% of the total human-caused methane is released by ruminant livestock. These creatures obtain nourishment by fermenting sustenance in stomachs consisting of four chambers, which are present in cows, sheep, and goats. They generate methane in two manners: via burping and from the breakdown of their excrement under specific circumstances.
Swedish researchers have analyzed the potential effects of introducing the tropical alga Asparagopsis taxiformis (AT), commonly referred to as red sea plume, to bovine excrement in relation to greenhouse gas emissions. Their findings on the impact of this addition to dairy cow manure have been published in Frontiers in Sustainable Food Systems.
"According to Dr. Mohammad Ramin, an animal science researcher at the Swedish University of Agricultural Sciences, our study demonstrated a notable 44% reduction in methane emissions from dairy cow feces when Asparagopsis taxiformis (AT) was added. Interestingly, we observed that the methane production from the feces of cows that received AT supplementation in their diet was not lower compared to the feces of cows that did not consume the alga."
Red sea plume fighting green(house) gas
AT, a red algae species found in tropical to warm waters worldwide, is known for its cosmopolitan distribution. The primary component of this algae is bromoform, which acts as a potent methane inhibitor by impeding the process responsible for methane generation. Currently, it stands as the most promising natural compound for mitigating methane emissions.
Dr. Mohammad Ramin highlighted that while numerous studies have investigated the use of AT in dairy cows' diets to mitigate enteric methane production, none of them have focused on the reduction of methane emissions specifically from manure.
Nevertheless, the addition of AT to cows' feed is not without potential side effects due to the algae's high iodine content. Studies have indicated that supplementing cow feed with AT can lead to increased iodine levels in milk, which is a consumable product for humans. While iodine is an essential nutrient, excessive concentrations can be toxic and result in health complications, particularly related to the thyroid. As a response, researchers are presently engaged in laboratory efforts to cultivate AT variants with reduced iodine content.
Indeed, it should be noted that AT can be utilized to mitigate methane emissions not only from cows' enteric fermentation but also from their manure. This was precisely the approach undertaken by Ramin and colleagues in their research.
Naturally less methane
The impact of manure on greenhouse gas emissions varies depending on various factors, including the conditions in which it is stored. In the cool-temperate climate of Europe, manure from the dairy system is estimated to account for roughly 12% of the total methane emissions.
Dr. Mohammad Ramin emphasized that methane production from manure does indeed contribute to global greenhouse gas emissions and warrants reduction efforts. He further stated that their study demonstrated a potential method for utilizing methane inhibitors to achieve this goal.
While the researchers obtained promising results, it is important to note that their study was a pilot study involving feces from only four cows. As a recommendation for future research, they suggested increasing the number of cows from which manure is collected to obtain a more comprehensive understanding. Additionally, they emphasized the need for further studies to explore the interactions between the halogenated compounds present in the alga and the fecal microbiome. Such investigations would contribute to a deeper understanding of the underlying mechanisms involved.
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