REVIEW METHODOLOGY

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Study design

This article was prepared as a structured narrative review to synthesize current evidence on the use of cassava processing residues as circular energy ingredients in dairy systems. The review was designed to integrate evidence across key themes relevant to practical dairy application, including residue stream classification, nutrient composition and variability, safety constraints, preservation and detoxification pathways, and ration level implications for lactating cows. Because the available literature comprises studies with heterogeneous designs, including feeding trials, in vitro studies, preservation experiments, and review articles, the evidence was synthesized narratively rather than quantitatively.

Literature search strategy

A structured literature search was conducted between December 2025 and January 2026 using the electronic databases Scopus, ScienceDirect, and Google Scholar. These sources were selected to capture the literature on cassava processing residues, dairy cow feeding, ruminant nutrition, preservation technologies, and feed safety issues. In addition, the reference lists of key review papers and relevant primary studies were manually screened to identify additional articles directly related to the review's objectives.

Search terms

The search strategy combined keywords related to cassava residues, ruminant feeding, dairy systems, preservation, and safety. Representative search terms included: “cassava pulp,” “cassava pomace,” “cassava bagasse,” “cassava peel,” “cassava residue,” “cassava waste,” “dairy cow,” “lactating cow,” “ruminant,” “silage,” “ensiling,” “fermentation,” “cyanide,” “hydrogen cyanide,” “mycotoxin,” “aerobic stability,” “feed safety,” “rumen fermentation,” and “milk production.” Search terms were combined using Boolean operators (AND, OR) and were adjusted as appropriate to the indexing and retrieval functions of each database.

Inclusion and exclusion criteria

The initial search identified 154 records, which were screened based on title and abstract, followed by full-text assessment where necessary. Studies were included if they were published in English and were directly relevant to the use of cassava processing residues in ruminant or dairy feeding systems. Eligible publications were required to provide information on at least one of the following aspects: residue stream identity, nutrient composition, physical characteristics, variability, safety constraints, preservation or detoxification strategies, rumen responses, digestibility, milk production, or milk composition. Studies were excluded if they were not published in English, focused exclusively on cassava for human food use without relevance to residue utilization, feed safety, or animal feeding, lacked sufficient methodological or technical detail, or were duplicate records or otherwise outside the scope of the review.

Data extraction and synthesis

For each eligible publication, information was extracted on residue type, processing origin, physical form, nutrient composition, physical characteristics, hazard profile, preservation or detoxification method, and reported effects on rumen fermentation, digestibility, milk production, milk composition, or practical feeding value. The retrieved evidence was then organized into thematic sections and synthesized narratively, with emphasis on stream-specific variability, risk-control logic, stabilization strategies, and ration level constraints relevant to lactating cows.

Scope of the review

This review focuses primarily on cassava processing residues in tropical and subtropical dairy systems, with particular relevance to smallholder and cooperative settings where cassava residues are regionally abundant and wet handling is common. However, the review also considers implications for more intensive and commercial dairy systems where tighter control of fermentability, physically effective fiber, and production responses is required. Evidence from dairy cow studies was prioritized, although selected studies in other ruminants were also included when they provided relevant mechanistic or applied insight into cassava residue utilization, preservation, or safety.