What is overmilking, and what can be done to avoid it?

Overmilking occurs when the milking unit remains on the cow after milk flow has dropped below a predetermined amount, usually in the range of 0.5 to 1 pounds per minute. Overmilking is something to be concerned about because it may have an adverse affect on teat condition and udder health.

Signs that overmilking is occurring in a herd may include some of the following symptoms:

•    Restless, stepping, kicking cows at the end of milking

•    Cows kicking off the milking unit

•    Discolored teats after the unit is detached

•    Ringing at the base of the teat after the milking unit is detached

•    Teats that are firm or hard to the touch

•    Cows reluctant to allow hand stripping after the milking unit is detached

•    High numbers of teats with excessive hyperkeratosis (thickening of the skin that lines the teat canal and surrounds the external teat orifice)

•    Nervous first-lactation cows

•    Cows reluctant to enter the parlor

•    Long milk hoses or claws without milk

To reduce the incidence of overmilking, dairy operators should work with their equipment dealer to adjust the automatic milker detacher settings to increase the threshold value for activating the detachers and/or decrease the delay time from when the threshold value is reached until the unit is removed.

Milking procedures also influence overmilking. Proper premilking teat preparation will ensure that cows are stimulated and the milk ejection response is fully evoked so that milk flows continuously shortly after the milking unit is attached.

Immediately after attachment, the milking unit should be adjusted to assure it has an equal weight distribution and is balanced on the cow’s udder. Observation of the milking units for two minutes after attachment and finding periods of no milk flow is indicative of poor udder preparation.

Dairy operators should evaluate their milking equipment and milking procedures and make the changes needed to minimize or eliminate overmilking. Cows will respond with short machine-on times, calmer behavior in the parlor or barn, better teat condition and proper milk-outs that require fewer adjustments by the milker.  EL