Genetic and phenotypic evaluation of milk production in Khuzestani buffalo under intensive farming conditions

• First genetic assessment of milk yield in Khuzestanian buffaloes under extensive systems. • Genetic and phenotypic trends demonstrate measurable progress in buffalo milk productivity. • Environmental and management factors significantly influenced yield and lactation curve in buffaloes. • Results provide a framework for sustainable breeding strategies in Iranian buffaloes. Understanding the productive potential of Khuzestani buffaloes is essential for improving dairy efficiency and supporting sustainable livelihoods in regions where this indigenous breed is central to agriculture. This study evaluated milk yield and genetic parameters of Khuzestani buffaloes managed under intensive farming conditions. A total of 33,521 test-day milk (TDM) records from 106 buffaloes collected between 2021 and 2025 were analyzed using polynomial mixed models adjusted for biological, environmental, and management effects. The 270-day milk yield (270DMY) was estimated, and variance components were derived using a Bayesian linear mixed model with Gibbs sampling. Average daily milk yield was 4.82 kg, with peak production observed between 50 and 75 days in milk and higher yields in animals milked without calves. The mean 270DMY was 1065 ± 355.8 kg, with a significant annual increase of 66.75 kg, indicating steady herd-level improvements. Genetic analysis revealed a moderate heritability for 270DMY (h² = 0.433) and a positive genetic trend of ∼28.5 kg/year in estimated breeding values, confirming measurable progress through selective breeding. As a first-step report focused on milk yield, we demonstrate substantial untapped genetic potential in Khuzestani buffalo and quantify key productivity drivers—milking type, season, parity, age at calving, and temperature. Overall, the findings provide the first comprehensive genetic evaluation of this indigenous population under standardized intensive farming with complete, verified management and pedigree records, establishing a framework for data-driven selection to enhance milk yield and resilience.