Cows, Red Seaweed, and Carbon — Unveiling the Connection
Written by Mallory Honan, Ph.D
More people are talking about cows than ever before
Over the past 50 years, the farming population of America has undergone significant changes. The number of farms in the United States has declined by approximately 4.8 million since the 1930s, while the average size of farms has increased. The decrease in the number of farmers can be attributed to several factors, including the rising financial and land barriers for new farmers, the high production costs, and the migration of population to urban areas.
Efforts have been made in recent years to support and encourage new farmers, particularly those from underrepresented communities. Programs such as the National Young Farmers Coalition, have been established to provide assistance to aspiring farmers and in 2022, the USDA announced a fund of $35 million through their Outreach and Assistance for Socially Disadvantaged Farmers and Ranchers and Veteran Farmers and Ranchers Program (also known as the 2501 Program). In 2017, 27% of the farming population was considered to be made up of ‘beginning farmers’ (The USDA defines beginning farmer as anyone who has farmed for 10 years or less) but the proportion of farmers that make up the consumer population has substantially diminished over the last century.
While efforts have been made to support and encourage new farmers, the decline in the proportion of farmers within the consumer population over the last century has created a significant gap in connecting with and understanding farming and food production.
Despite this shift, the conversation surrounding agriculture, particularly in the context of livestock production, has reached unprecedented levels in recent years. There is now a wealth of information available on the topic, saturated with divergent viewpoints ranging from the cinematic polemics of "Cowspiracy" to the literary advocacy of Judith D. Schwartz's "Cows Save the Planet." Some question the role of meat and dairy in our food system due to concerns about their environmental impact. Conversely, advocates of maintaining cattle underscore their profound value by effectively converting by- and co- products from our food chain into bioavailable sources of meat, milk, and other materials. These proponents emphasize the nutritional benefits and economic significance derived from these end products, highlighting the multifaceted role that cattle assume in our agricultural landscape. The debate extends beyond traditional agriculture and environmental circles, reaching industries like fashion, food, and technology.
And they’re talking about… burps?
Yes, some of the conversation around cows has revolved around their burping. But why?
Cattle possess a remarkable digestive system primarily characterized by a voluminous stomach known as the rumen, with a capacity exceeding at least 20 gallons. Unlike other typical stomachs, the rumen does not produce or secrete any enzymes; instead, it provides a habitat for trillions of microorganisms that possess their own enzymatic activity.
The rumen can be seen as an expanded counterpart of our colon with dense microbial environments (Kelly et al., 2022). However, the human colon plays a supporting role in digestion in comparison to the high-capacity rumen due to ranking of responsibilities within the digestive tract. The colon's primary function is to absorb nutrients and remove water from waste materials and the rumen is a specialized system designed to tackle the unique challenges of breaking down plant materials for grazing species. The fermentative rumen located at the front of their gastrointestinal tract releases gaseous byproducts a lá anterior, rather than posterior.
In comparison to non-ruminant animals, they are less efficient as production animals (output:input), with up to 12% of dietary energy lost as methane through ruminal fermentation. Yep, you heard it right—some of that energy goes out in their burps! It's like a little reminder of the first law of thermodynamics: energy can't be created or destroyed, only transferred or transformed. This energetic shortfall results in not only diminished energy for the animal but also environmental consequences, adding to the atmosphere’s warming with methane gas. In fact, enteric fermentation from livestock is responsible for approximately 16% of global methane emissions. Continuing with the prevailing pattern, it comes as no surprise that the conversation surrounding the relationship between cows and carbon is yet another topic that elicits a wide array of viewpoints.
Science behind the burps
Despite initially discussing the potential drawbacks, the synchronized workings between the microorganisms inhabiting a cow's rumen are nothing short of extraordinary. Through their evolved symbiotic relationship, they work together in a harmonious manner, offering a multitude of benefits for both the cow and the microorganisms themselves (Russell, 2002).For instance, certain bacteria play a crucial role by producing enzymes that break down complex carbohydrates into simple sugar units and then engage in the fermentation process, utilizing these sugars for their own energy purposes. As a result, the rumen reaps the rewards of this collaboration, obtaining energy from the byproducts of fermentation (volatile fatty acids) and eventually benefiting from the microbial protein that is passed along from the rumen (Lopez, 2012).
Bacteria are the dominating microbe with populations of over a billion cells per milliliter of rumen fluid and can metabolize a variety of ingested substrates (Makkar and McSweeny, 2005). Protozoa, on the other hand, play a crucial role in regulating the rumen pH by consuming bacteria and other microbes that produce excess acid (Mackie et al., 1978; Newbold et al., 2010). Fungi are also present in the rumen and help break down lignin, a complex compound found in plant cell walls, which further aids in the digestion of plant materials (Ushida et al., 1997). Rumen archaea are less than 5% of the rumen population and are commonly referred to as methanogens because they are the only known microorganism in the rumen that produces methane (Matthews et al., 2019).
Methanogenesis, the production of methane by archaea, can be beneficial because it participates in ruminal hydrogen flow by removing excess hydrogen ions generated during the microbial fermentation of complex carbohydrates (Janssen and Kirs, 2008; Ungerfield, 2010). The ongoing fermentation processes produce large amounts of fatty acids, major energy precursors for ruminants, which can build up and decrease the pH of the rumen, contributing to a condition called acidosis which can dismantle fiber digestion capabilities (Nagajara and Titgemeyer, 2007). Methanogens utilize hydrogen ions and CO2 to produce methane gas, which is then belched out of the cow, helping to maintain a healthy pH balance. Methanogenesis has been a normal function of the rumen's microbial ecosystem, as it allows for the efficient and continuous breakdown of plant material for the production of energy and nutrients.
If this is a natural route of the metabolism, why would we want to interfere?
The symbiotic relationship between the ruminant animal and the microbes in the rumen is critical for the animal's survival and growth. However, microorganisms are typically equipped with many different pathways which require unique substrates, allowing them to be convinced to explore different routes of metabolism or terminate their mission prematurely without necessarily detrimenting overall metabolism of the animal. Some of these other pathways still utilize hydrogen (Ortiz-Chura et al., 2021), thus taking over some of the role of methanogens, or in other cases, the amount of hydrogen exhaled by the animal can increase (Glasson et al., 2022). Feed additives with unique properties have been explored in cattle that modify the rumen environment to the extent of reducing the amount of methane produced and released (Beauchemin et al., 2020; Fouts et al., 2022)
Are we finally going to talk about seaweed?
Yes, thank you for your patience, let's get started. Species of seaweed (also called macroalgae) are broadly classified into three main groups based on their pigmentation and cell structure: brown algae (Phaeophyceae; 1,500-2000 species), red algae (Rhodophyta; 4,000-5,000 species), and green algae (Chlorophyta; 6,000-8,000 species) (Chapman, 2010). The variety of species are equipped with unique characteristics and applications, including as a food source, fertilizer, industrial material. Many seaweeds contain a concentrated blend of amino acids, polysaccharides and mineral content up to 10 times greater than soil grown plants. This is due to the fact that seaweed, unlike their terrestrial counterparts, have an impressive bioaccumulation ability, effortlessly absorbing vital nutrients directly through their fronds from the seawater. Red seaweed, particularly a species named Asparagopsis taxiformis, has a unique halogen present in its tissues known as bromoform.
Bromoform is effective in significantly reducing methane production in the rumen, thus aiding in sustainable efforts (Glasson et al., 2022). Red seaweed contains high concentrations of halogenic compounds such as bromoform which serve as competitive inhibitors of the methanogenesis pathway by inhibiting the final catalysis step. Studies in dairy and beef cattle have shown up to 60-98% reduction in enteric methane production when supplemented with Asparagopsis (Roque et al., 2019; Kinley et al., 2020; Roque 2020). To date, no other feed additive has demonstrated the same level of potential in reducing enteric methane emissions as A. taxiformis.
Meet SeaGraze™
SeaGraze™ is made from a single ingredient, Asparagopsis taxiformis with the help of our team at Symbrosia. SeaGraze™ is grown, harvested and dried using a process that retains the natural bioactive compounds as much as possible with shelf-life on the farm kept in mind. Symbrosia has built up a proprietary seed bank consisting of multiple strains of Asparagopsis that are selectively bred for optimal growth and bioactive compound content enabling us to produce high quality Asparagopsis. We look forward to sharing research related to red seaweed but more specifically, SeaGraze™, with you all.
Stay tuned for upcoming blog posts where we delve deeper into the present state of farming, explore the diverse perspectives surrounding the subject matter, explore the science, and introduce the solution that we have dedicated our efforts to, supported by relevant literature.
About Mallory
Mallory, an animal scientist, specializes in sustainable cattle nutrition and management and is Symbrosia’s Product and Animal Science Lead. With a BS and MS in Animal Sciences from The University of Vermont, and recent PhD from the University of California Davis, Mallory is committed to assisting producers in adopting and implementing SeaGraze within their herd in a cost effective and scientifically-backed manner.