Circular food resources as feed in South Asia: practices, gaps and implications for livestock systems – a systematic review with a focus on dairy production

This review explores the potential of circular food resources (CFRs) as animal feed in South Asian countries, with particular attention to dairy production systems. The review examines how CFRs are produced and supplied, identifying barriers to adoption, and evaluating existing governance and management frameworks to enable their integration into dairy feeding systems. A total of 24 research articles published in English between 2000 and 2025 met the selection criteria. Studies were included if they addressed CFRs in relation to feed types, processing methods, revalorization, life cycle assessments, circular economy models, relevant legislation, incentives and barriers to adoption. A thematic analysis was conducted to identify key patterns, trends and gaps in literature using MAXQDA. The review highlights that a large share of organic CFRs comes from private households, supermarkets, the hospitality sector and food industries. However, CFR management is still dominated by uncontrolled dumping and open burning, and only limited quantities are reused as feed, even though they could serve as a potential feed resource for dairy animals. Urban and peri-urban dairy farmers face adoption barriers such as contamination with inorganic materials, lack of regulation, insufficient nutritional, hygienic and safety data, and low awareness of impacts on animal performance. At conceptual level, the lack of integrated frameworks and stakeholder engagement limits the development of circular practices. At governance level, weak regulations and coordination hinder policy support. At management level, insufficient data on nutrition, safety, hygiene and regional availability highlight the need for context-specific evidence. Building on the synthesized findings, the review proposes a Strengths, Weaknesses, Opportunities, and Threats (SWOT) framework to evaluate the opportunities and risks of integrating CFRs into feeding systems. Transitioning from fragmented efforts to systemic change in CFRs-to-feed will require an interdisciplinary and multi-stakeholder approach, to build resilient and sustainable circular food systems in South Asian countries and beyond.