Differential responses of low- and high-flow dairy cows to automatic cluster removal and dynamic pulsation settings

The objective of this study was to quantify the effects of automatic cluster removal (ACR) and dynamic pulsator settings on milk yield, milking time, and milk flow characteristics in dairy cows differing in intrinsic milk flow capacity. A total of 104 spring-calving cows were classified as high- or low-flow and assigned to 4 milking treatments combining static or dynamic pulsation with 2 ACR switch-points (0.2 or 0.8 kg/min). Cows rotated through all treatments in a balanced 8-week crossover design. Milking duration, flow variables, and teat condition scores were analyzed using mixed models with repeated measures. Increasing the ACR threshold from 0.2 to 0.8 kg/min reduced total milking duration by 25% to 28% and overmilking time by 27 to 28 s without affecting yield or milk composition. Dynamic pulsation exerted smaller but consistent effects, slightly increasing average milk flow rate (+1%). Significant treatment × flow rate interactions were detected for milking duration and average milk flow rate, indicating greater relative efficiency gains among low-flow cows. The probability of firm teat ends declined from 8.4% to 3.8% and ringed teat barrels from 8.3% to 4.8% as the ACR threshold increased. Teat tissue responses were similar across flow rate classes, whereas efficiency traits remained flow dependent. These findings provide both physiological and practical evidence that adaptive detachment and pulsation control can improve milking efficiency and teat health across heterogeneous cow populations.