Impact of dry-off management in robotic milking systems on milking behavior, milk yield, and somatic cell count.
The objective of this study was to determine the effect of dry-off management of cows milked in automatic milking systems (AMS) on milk yield, milking behavior, and SCC. In 5 commercial dairy farms in Quebec, Canada, 341 cows were assigned to 1 of 4 treatments for 2-wk before dry off: 1) reduced milking (RM: 2x/d or if expected to yield 17 kg/milking; n = 95), 2) reduced feeding (RF: 0.75 kg AMS pellet/d for wk 1, 0.5 kg AMS pellet/d for wk 2; n = 98), 3) reduced both feeding and milking (RB: n = 73), and 4) a control (C: n = 75) group. Non-reduced milking allowed up to 6 milkings/d or as often as a cow was expected to yield 6 kg/milking. Non-reduced feeding allocated up to 2 kg/d of AMS pellet. From the AMS software, feed and milking behavior data were collected, as well as milk yield and SCC. Data on milk yield, milking frequency, and SCC were analyzed using mixed-effect linear regression models. The RB group had the lowest milk yield 3 d before dry-off, and was different from the C group (19.3 vs. 22.4 kg/d; SE = 1.08; P = 0.01). The RB group also differed from the C group in their reduction in total milk yield over the 2-wk treatment period (−4.9 vs. −1.8 kg; SE = 0.91; P = 0.02), indicating that this was the most efficient way to decrease milk yield before dry-off. Milking frequency was greater (SE = 0.09; P < 0.001) in the RF (2.25 ×/d) and C (2.65 ×/d) groups compared with the RM (1.60 ×/d) and RB (1.51 ×/d) groups. There was a difference (P < 0.001) in milking frequency between the RF and C groups, indicating that reducing feeding without altering milking frequency before dry-off may also decrease the motivation for cows to visit the AMS. There were no differences between groups (P > 0.24) for milking frequency or yield in the next lactation. SCC was not different (P > 0.35) between groups in the week before dry-off nor in the first month after calving. Overall, these data suggest that reducing both milking frequency and feed quantity in the AMS is the most efficient method to decrease milk yield before dry-off, without negatively influencing milking frequency or yield in the next lactation, as well as without affecting SCC.