Ruminants as Part of a Sustainable Agriculture System

By: Samantha Clark, Logan Thompson Ph.D., and Kim Stackhouse-Lawson Ph.D.

Every person needs food, and should have access to a safe, nutritious, and affordable diet. All food production produces greenhouse gases, whether plant or animal sourced, and humanity depends on agriculture for food production. Livestock have an important role in the economy, culture, ecosystems, health, and more. Agriculture, including livestock production, has been an important sector of the U.S. economy and is vital to the success of rural areas. A successful agriculture sector supports economic growth overall, as agriculture provides nutritious food across the country.

Ruminants are upcyclers that can utilize marginal land and can convert human-inedible plant proteins, human food leftovers, and byproducts into high-quality protein, rich in micronutrients (Place, 2017; Fessenden, 2020). They can graze land that is unsuitable for other uses, allowing for profit, and food production in rural areas. Grazing land can provide multiple environmental benefits to the soil, biodiversity and wildlife, and reductions in global greenhouse gas emissions (Varijakshapanicker et al., 2019). Grazing ruminants can promote habitat for wildlife species, and help preserve water sources. Managed livestock systems can play a large role in carbon management. Grazing lands can sequester carbon from the atmosphere, acting as a carbon sink, and/or store and protect carbon already present in the soil (Sollenberger et al., 2019). Ruminants also play an important role in the biogenic carbon cycle (Thompson and Rowntree, 2020). Plants capture atmospheric carbon through photosynthesis, and ruminants are able to convert that carbon into usable end products. Ruminants respirate and excrete part of the carbon they ingest back into the atmosphere, where it can be broken back down into carbon dioxide or incorporated into soil for utilization. 

Humans need carbohydrates, protein, fats, essential amino acids, vitamins, and minerals (Varijakshapanicker et al., 2019). Animal-sourced foods contain sources of energy, protein, minerals, and vitamins, and provide a balanced profile of amino acids. They provide many of the nutrients that are lacking or less bioavailable in plant-based foods. Animal-sourced foods are the best nutrient-dense foods for children ages 6-23 months (Adesogan et al., 2019). Intake of animal-sourced foods improves growth, physical activity, and leads to better pregnancy outcomes and reduced morbidity from illness (Adesogan et al., 2019). People in low- and middle-income countries have improved health outcomes when provided low to medium levels of ruminant products (Adesogan et al., 2019). If animal-sourced foods were removed from U.S. diets, micronutrient deficiencies would prevail (White and Hall, 2018).

It is important to also consider that livestock animals contribute to multiple different products, not just human food. They are also important for production of leather products, pharmaceuticals, cosmetics, pet food, and so much more (Banda and Tanganyika, 2021). Livestock production is also needed for wax paper, crayons, paints, rubber, lubricants, candles, soaps, lipsticks, shaving creams, and other cosmetics. Animal manure is also commonly used as natural fertilizer, as insect repellant and is increasingly being utilized to produce bioenergy. Livestock can be utilized in weed control using targeted grazing, and to clear crop residues after harvest. Some ruminants, especially sheep, also provide fiber that can be used for clothing, insulation, and bedding.

Bottom Line: Livestock are an important part of Food Systems, and necessary for sustainability.



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