Where are we with Milking Machine Tests
ISO 3918 (2007) defines four types of milking machine tests:
Dry test -test made on a milking machine without any liquid.
Wet test -test made on a milking machine with simulated milking.
Milking time test -test made on a milking machine during milking of live animals.
Cleaning time test -test made on a milking machine during cleaning
The revised 2012 NMC publication; “Procedures for Evaluating Vacuum Levels and Air Flow in Milking Systems” recommends first performing milking time testing, and states that “dry” (static) testing should be used to identify why a system does not meet the milking time testing guidelines".
After more than a century of trial and error, most pulsators are now set within a relatively narrow range, mainly because milking speed is optimized when the duration of the B-phase is between 500-600 milliseconds
The primary purpose of pulsation is to limit the development of congestion and edema in the teat tissues during machine milking by providing massage to the lower part of the teat during the D phase.
The mean compressive pressure (force) applied to the inner tissues of the teat apex by the liner during the d-phase of pulsation, in order to relieve congestion and edema that develops during the b (milk) phase
The mean compressive pressure, above that required to stop milk flowing from the teat, which is applied to the inner tissues of the teat apex by the liner during the d-phase. Thus, overpressure is a component of liner compression.
Over-milking starts when the milk flow to the teat cistern is less than the flow out of the teat canal.