A technique for monitoring the movement of the teatcup liner during mi
lking, using video recordings, has been investigated. The liner was vi
deoed through a transparent shell and the recordings were subsequently
processed frame by frame by an image analyser. The width of the liner
and its variation with pressure difference across the liner walls wer
e calculated at several locations along the liner length, and analysis
of these results allowed the pressures at which the liner buckled and
the walls touched to be determined and some estimate of the degree an
d duration of liner collapse to be made.