Dairy cow behavior affects the availability of an automatic milking system

Facility design can affect the accessibility of an automatic milking system (AMS). In particular, gates and alleys positioned around the AMS may affect cow traffic and cow behavior, potentially affecting the duration of time the AMS is available for milking. Eighty-four Holstein cows of various parities and days in milk were randomly divided between 2 groups, each group having access to its own AMS. Cow locations and behaviors in the AMS entrance and exit areas, as well as in the adjacent holding area, were recorded continuously for 14 d. Cows receiving a "no-milking" decision (i.e., cow is rejected from the milking stall due to a recent milking event) took longer to exit the milking stall (18.2±1.33 s), and were more likely to circle and re-enter the AMS (0.8±0.15) compared with cows receiving a milking decision (16.2±1.09 s; 0.2±0.03). Cows exiting the AMS hesitated for long periods when another cow was near the exit gate (192.93±1.11 s) or in the general holding area (101.04±1.07 s). Cows in late lactation had a greater probability of hesitating in the exit alley for long periods (0.55±0.09) compared with cows in early lactation (0.15±0.07), regardless of whether cows were in the holding area. Primiparous cows were more likely to block other cows trying to exit (0.60±0.13) compared with multiparous cows (0.29±0.09). Occasionally, blocking events led to "back-up" events, in which the AMS became unavailable for new cow access due to a back up of cows through the exit alley into the milking stall. The AMS was empty (not occupied) for 10 and 18% (groups 1 and 2, respectively) of the day; therefore, it was possible that back-up events would simply reduce the amount of time the AMS was empty. The duration of back-up events and AMS empty events had a negative relationship in group 1 (r=-0.74), but no such relationship was observed in group 2. The differences in time budgets between the 2 groups suggest that the effect of back-up events on AMS availability may be dependent on group social dynamics.