Milkability in Dairy Species: A Comparative Field Study on Milk Flow Dynamics in Cattle, Buffaloes, Sheep, Goats, and Donkeys Using an Electronic Milk Meter

Milk flow dynamics during mechanical milking are strongly influenced by species-specific mammary anatomy, milk partitioning between cisternal and alveolar compartments, and milking management. The present study aimed to compare milkability traits across the main dairy species reared in central Italy using a large dataset collected over 20 years. A total of 7315 animals were included: dairy cows (1103), buffaloes (2870), goats (2399), sheep (754), and donkeys (189). Milk flow curves were recorded using a portable Lactocorder® device. The following traits were analyzed: milk yield (MY), lag time (LT), milk ejection time (MET), total milking time (TMT), peak flow rate (PFR), average flow rate (AFR), plateau phase (PL), bimodal phase (BM), and bimodality incidence (Bimo). Marked interspecific differences emerged. Dairy cows showed the highest MY and PFR, with bimodality occurring in 23.7% of curves. Buffaloes exhibited lower flow rates, prolonged LT, and extended TMT, reflecting their strong dependence on oxytocin-mediated alveolar milk ejection. Sheep demonstrated short milking times and low bimodality (13.5%), consistent with their large cisternal milk fraction. Goats displayed breed-dependent variability, with specialized dairy breeds showing higher PFR and longer TMT. Donkeys produced low milk volumes but exhibited rapid and efficient milk flow, with the lowest incidence of bimodality (7.4%). Overall, milk flow patterns reflected species-specific udder morphology and physiological mechanisms of milk ejection. Although this field-based study faces inherent limitations in environmental and protocol standardization across farms, the resulting long-term dataset remains highly representative. These findings highlight the importance of tailoring milking machine settings and prestimulation protocols to species and breed characteristics to optimize milking efficiency, labor management, and animal welfare.