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Effects of Automatic Milking-unit Detacher Settings

Dairy Pipeline: October 1999

Ernest Hovingh
Extension Dairy Veterinarian
Virginia-Maryland Regional College of Vet Medicine
Virginia Tech
(540) 231-5234

The effect of different automatic milking-unit detacher settings. During machine milking the milk flow from a normal udder does not occur at a constant rate. After the milking unit is attached the flow rate increases over about 30 to 60 seconds to a maximum flow rate which is generally maintained for about 2 minutes. Milk flow rate then decreases gradually. Automatic milking unit detachers are usually set to detect the flow rate of milk from the udder and remove the unit once the flow rate falls below a selected level. Research using 1,565 Holstein cows carried out in Pennsylvania and presented at the 1999 annual meeting of the American Dairy Science Association investigated the effect of different detacher settings on milk yield, milking time, and somatic cell score. When the detacher was set to remove the unit only after a very low flow rate (.5 lb/min) of milk was detected, the milk yield per cow per milking was increased (average 26.4 lb), as was the milking time per cow (average 5.75 minutes). Conversely, when the detacher was set to remove the unit at a higher flow rate (2.5 lb/min), the milking time per cow was decreased (average 4.55 minutes), as was the milk yield per cow per milking (average 24.9 lb). The investigators also examined the effect of the detacher setting on the somatic cell score (SCS) of the cows. They found no significant difference in the SCS at the different settings that they used.

The results of this research indicate that a producer can make decisions about the automatic unit detacher settings so as to optimize the balance between milk yield, parlor throughput, and worker efficiency without undue concern for the effect on udder health. It is important to note, however, that consistent and considerable overmilking should be avoided, and that even at the very low detacher flow rate setting in this research, the average milking time was less than 6 minutes.

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