Circular Economy in Animal Husbandry: A Critical Review of Resource Cycling, Environmental Trade-offs and Implementation
J. B. Butani *
Krishi Vigyan Kendra, Navsari Agricultural University, Vyara, Tapi, India.
R. R. Singh
Department of Livestock Production and Management, CoVS & AH, KU, SK Nagar, India.
V. R. Patel
Department of Animal Nutrition, CoVS & AH, KU, Himmatnagar, India.
*Author to whom correspondence should be addressed.
Abstract
Animal husbandry occupies a contested position in sustainable food-system transitions. Livestock can convert grass, crop residues, agro-industrial co-products and food-chain losses into nutrient-dense foods while returning manure and other biological resources to productive use. Yet conventional livestock systems can also intensify competition for arable land, concentrate nutrients, generate greenhouse gases and create animal-health and environmental risks. This critical narrative review evaluates whether, and under which conditions, circular-economy strategies improve the sustainability of animal husbandry. The reviewed evidence was organized around circular feeding, crop–livestock recoupling, manure-derived nutrients and energy, slaughter and processing by-product valorization, life-cycle performance, One Health safeguards, and the economics and governance of implementation. The synthesis indicates that the strongest circular functions of livestock arise when animals consume low-opportunity-cost biomass, when manure nutrients are matched spatially and temporally to crop demand, and when recovery technologies displace virgin fertilizers or fossil energy rather than merely adding new processing stages. Benefits are less certain when transport distances are long, nutrient surpluses remain unresolved, co-product credits dominate life-cycle results, or recycled inputs introduce pathogens, contaminants, antimicrobial resistance determinants or nutritionally variable feed. Circularity, therefore, cannot be treated as a proxy for sustainability. It requires a hierarchy that prioritizes waste prevention and direct human use before feed, material, nutrient, and energy recovery, together with explicit safeguards for animal health, welfare, food safety, and ecological integrity. Current evidence is constrained by inconsistent system boundaries, limited multi-year whole-farm trials, geographical concentration and weak integration of biophysical, economic and social outcomes. A credible transition towards circular animal husbandry depends on context-specific design, harmonized indicators, traceable resource flows, enforceable safety standards, regional nutrient planning, and business arrangements that distribute costs and value across farmers, processors, and consumers.
Keywords: Circular bioeconomy, low-opportunity-cost feed, crop–livestock integration, manure management, nutrient recovery, animal by-products, life-cycle assessment, one health