Milking Characteristics of Teatcups with Reduced Liner Wall Movement

To evaluate effects of reduced liner wall movement on milking performance and pressure gradient across the short milk tube, we developed and compared four experimental teatcup assemblies to a conventional unit. These assemblies were 1) a conventional liner with restricted liner wall movement, 2, 3) two partial liners of different lenghts, and 4) a partial liner equipped with a mouthpiece adapter. In three of the four experiments, milking performance was evaluated. In the fourth experiment vacuum conditions and reverse pressure gradients across the short milk tube were measured. The long partial liner resulted in longer milking time and lower peak milk flow rate than the control (7.6 versus 5.9 min and 2.5 versus 3.2 kg/min). The difference in milking time was eliminated when the mouthpiece adapter was included. Characteristics of milking performance of the restricted liner were similar to the control with the exception of peak milk flow rate, which was decreased for the restricted liner (3.3 versus 3.6 kg/min). Reverse pressure gradients were measured across the short milk tubes of the conventional liner (−4 kPa) and the restricted liner (−2 kPa). Reverse gradients were practically nonexistent for the partial liner assemblies.