Regenerative agriculture is a newly codified approach to agriculture that emphasizes reducing reliance on exogeneous inputs, as well as restoring and enhancing ecosystem services such as soil carbon (C) sequestration. These regenerative agriculture principles suggest that modern livestock systems can be redesigned to better capitalize on animals' ecological niche as biological up cyclers and may be necessary to fully regenerate some landscapes. One example is a multispecies pasture rotation (MSPR) system, which symbiotically stacks multiple animal production enterprises (i.e., chickens, cattle, sheep, and pigs) on one landscape. We conducted a whole-farm life cycle assessment (LCA) of an MSPR in the southeastern United States that was originally converted from degraded cropland. We compared the production outputs, greenhouse gas (GHG) emissions, land footprints, and soil health outcomes to a conventional, commodity (COM) production system of each respective species. Our 20-year MSPR chronosequence of soil C and other soil health indicators shows dramatic improvement since establishment, sequestering an average of 2.29 Mg C ha−1 yr−1. Incorporation of soil C sequestration into the LCA reduced net GHG emissions of the MSPR by 80%, resulting in a footprint 66% lower than COM. However, when comparing required land between the two systems for food production, MSPR required 2.5 times more land when compared to COM. Thus, while our model indicates that MSPR can simultaneously produce protein while regenerating land, a considerably greater land area is needed when compared to COM. Our results present an important yet paradoxical conclusion on land and food production balance. Should society prioritize an input-intensive, COM system that produces more food from a smaller yet degrading land base? Or, alternatively, should systems such as MSPR that produce less food on a larger, but more ecologically functional landscape be more highly prioritized? These complexities must be considered in the global debate of agricultural practice and land. Our results indicate MSPRs are a useful model for alternative livestock production systems with improved environmental outcomes, but in this study may present considerable land-use tradeoffs.
The animal production sector is facing important challenges in the context of global change. This is especially related to population growth, land erosion, a decrease in biodiversity, wastage of water, depletion of resources, disruption of nutrient cycles and eutrophication, and climate change. Even if livestock agriculture has contributed to these problems, as have other forms of human productivity, it can contribute to the solution, provided it operates within an agroecological framework and environmental boundaries, while still respecting primordial principles of diversity ( Leroy et al., 2022). The latter relates not only to the biological variety of livestock options as such, but also to the important heterogeneity within ecosystem types, production and management methods, and local needs and resources. Indeed, livestock products and production systems differ, from intensive to extensive, from arctic to tropical, from highly technological to indigenous, or from being a by-product to being the main focus of the system.
Grazing land ecosystem services including food provision and climate regulation are greatly influenced by soil health. This paper provides a condensed review of studies on the response of three important soil properties related to soil health to grazing land management: water infiltration, carbon (C) sequestration, and nitrogen use efficiency (NUE). Impacts of management strategies that are often used in grazing lands are discussed in this review including vegetation composition, grazing methods, and other factors such as fertilizer use and climatic conditions. In general, proper grazing management such as continuous moderate grazing and rotational/deferred-rotational grazing with low or moderate stocking rates tends to benefit all three soil properties. Water infiltration can usually be increased with full vegetation cover, increased soil C, and aggregate stability, or be decreased with greater soil bulk density. Adoption of highly productive plant species with faster turnover rates can promote soil C sequestration by increasing C input. However, excessive C removal from ecosystems due to overgrazing or improper soil fertilization management results in higher C loss, which can have detrimental effects on soil C sequestration. Proper stocking rate and a balanced manure/fertilizer management was found to be critical for enhancing NUE. Grazing land management sometimes simultaneously influence the three soil properties. Techniques that can increase soil C such as introduction of high productive plant species can often promote water infiltration and soil nitrogen (N). Some other practices such as adoption of N fertilizer may enhance C sequestration while being detrimental to NUE. An integrated management plan for a specific location or farm should be considered carefully to improve soil health as well as ecosystem production. This review provides farmers and policy makers the current state of general knowledge on how health-related soil processes are affected by grazing land management.
There is increasing interest in using grass-fed beef (GFB) by-products to augment the nutrient profile of eggs among local pasture-raising systems in the US. The objective of this study was to characterize egg yolk fatty acid and antioxidant profiles using eggs from pasture-raised hens fed a corn- and soy-free diet and supplemented with GFB suet and liver compared to eggs from pasture-raised hens fed a corn and soy layer hen feed and commercially obtained cage-free eggs. The egg yolk vitamin and mineral profile was also assessed by a commercial laboratory. Both pasture-raised groups had twice as much carotenoid content, three times as much omega-3 fatty acid content, and a 5–10 times lower omega-6:omega-3 fatty acid ratio compared to the cage-free eggs (p < 0.001). Eggs from hens fed a corn- and soy-free feed and GFB by-products had half as much omega-6 fatty acid content and five times more conjugated linoleic acid, three times more odd-chain fatty acid, and 6–70 times more branched-chain fatty acid content (p < 0.001). Feeding pasture-raised hens GFB suet and liver reduces agricultural waste while producing improved egg products for consumers, but further research is needed to quantify optimal supplementation levels and the efficacy of corn- and soy-free diets.
Grass-finished beef (GFB) can provide beneficial bioactive compounds to healthy diets, including omega-3 polyunsaturated fatty acids (n-3 PUFAs), conjugated linoleic acid (CLA), and secondary bioactive compounds, such as phytochemicals. The objective of this study was to compare fatty acids (FAs), micronutrients, and phytochemicals of beef fed a biodiverse pasture (GRASS), a total mixed ration (GRAIN), or a total mixed ration with 5% grapeseed extract (GRAPE). This was a two-year study involving fifty-four Red Angus steers (n = 54). GFB contained higher levels of n-3 PUFAs, vitamin E, iron, zinc, stachydrine, hippuric acid, citric acid, and succinic acid than beef from GRAIN and GRAPE (p < 0.001 for all). No differences were observed in quantified phytochemicals between beef from GRAIN and GRAPE (p > 0.05). Random forest analysis indicated that phytochemical and FA composition of meat can predict cattle diets with a degree of certainty, especially for GFB (5.6% class error). In conclusion, these results indicate that GFB contains higher levels of potentially beneficial bioactive compounds, such as n-3 PUFAs, micronutrients, and phytochemicals, compared to grain-finished beef. Additionally, the n-6:n-3 ratio was the most crucial factor capable of separating beef based on finishing diets.