The objective of the paper was to determine models describing changes of the selected milking parameters i.e. average suction negative pressure pss, amplitude of suction negative pressure aps,amplitude of massage negative pressure apm in the measuring milking machines (of the selected companies) from changes of disturbance amplitude Pmax. Measurement machines were connected to the pipe milking machines installation in the first stand tap (towards the final unit) with the set stream of liquid outflow Qm = 2 and 6 l·min-1. Models of changes of the above mentioned parameters were developed for regular operation of the pipe milking machine (system negative pressure oscillations- cyclic) and after introducing disturbance (negative pressure oscillations - irregular). For comparison of the milking machines, products of five companies were selected. The same machines of the given company (6 items) were enclosed to the milking machine installation. Characteristic parameters of models were described: gradients a, absolute terms b. Resistance (sensitivity) of the milking machine is higher for the selected milking parameter if the change of this parameter caused by disturbance is lower. Selected models enable assessment of the milking parameters resistance to disturbances.