Physico-chemical properties of milk and butter along the supply chains in smallholder dairy productions systems in Southern Ethiopia

This study addresses the lack of comprehensive evaluations of the physico-chemical quality of raw milk and major dairy products, such as butter across supply chains and dairy production systems (DPSs) in Southern Ethiopia. Interviews with 360 dairy producers from Cash Crop Based (CCB), Enset Based (EB), Cereal Based (CB), and Diversified Crop Based (DCB) systems were conducted, along with group discussions to map the supply chains. For physicochemical analysis of milk and butter, samples were collected from CCB and EB systems, which vary in farming system and feed type. Results showed that milk supply chains ranged from short (producers directly to consumers) to longer chains (producers-collectors-cooperatives-consumers). Butter supply chains followed similar patterns, with both short and longer chains (producer-retailer-collector-wholesaler-consumer). The physico-chemical quality of raw milk significantly declined (p < 0.05) from producers to retailers (fat: 5.3% → 4.3%, SNF: 7.9% → 7.5%, TS: 13.2% → 11.8%), likely due to adulteration. Retailers’ milk had higher water content (10.8%) compared to consumers (7.3%) and producers (5.7%). Enset-based systems had higher fat and TS levels than CCB, attributed to diverse feed sources. Butter quality also dropped from producers (fat: 85%, moisture: 15%) to retailers (fat: 78%, moisture: 18%). Saturated fatty acids (SFA) were highest in retailers (67%) compared to producers (65%) and consumers (55%). Overall, milk and butter quality declined along the supply chain, with EB systems outperforming CCB. Strengthening post-production quality control and training for retailers is crucial to preserving quality and understanding its nutritional implications.