Effects of bail activation sequence and feed availability on cow traffic and milk harvesting capacity in a robotic rotary dairy

This study was conducted to investigate the effects of different bail activation sequences in combination with feed availability on cow traffic and harvesting capacity in a novel prototype robotic rotary (RR; DeLaval AMR, Tumba, Sweden). The RR can milk up to 50 cows/h. However, in voluntary cow traffic systems, the number of cows presenting may be low at certain times of the day (or during certain months or seasons in seasonal calving systems). In these circumstances, the ratio of active bails to the number of cows available may be undesirably high, with consequential negative effects on system efficiency and milk quality (the RR does not flush individual units automatically after each milking). Activating only 50% of the bails may be a management strategy chosen to cope with periods of underutilization. Four treatments with a total activation of 50% of bails [8 bails with activation sequences of 8, 4, 2, or 1 consecutive bail(s)], with or without the presence of feed on the RR, were observed during sixteen 4-h observation periods after a system wash. The absence of feed resulted in a significant increase in the proportion of available bails remaining idle, but no significant differences were observed across the 4 bail activation sequences. Overall, the effect of bail activation sequence on cow traffic was negligible, but the sequences that had more consecutive bail activations resulted in more robot operations being conducted simultaneously and more milk being harvested per minute of robot operation time. A feeding function upon entry to the RR platform, in combination with bails activated sequentially, would lead to a more efficient use of the RR.