Teatcup Liners Liners should have a barrel diameter about 1 or 2 mm less than the average diameter of the teats after milk letdown. Liners should be designed to fit the teatcup shells. The mouthpiece should not be distorted by the cup. Liners should have no cracks in the short milk tube connecting to the claw, and no surface crazing or swelling evident on the mouthpiece lip or inner barrel. Liners should be long enough to collapse below the teat.
Pulsation fails if the liners are unable to collapse because the teat penetrates too deeply.
The air vents in the claw or teatcups should be clear and unblocked. The hole in the claw is usually about 0.8-1.0 mm in diameter. Claws that have an effective volume of at least 120 ml below the milk inlet nipples help to reduce possible problems of flooding and cross-contamination between the teatcups within a cluster. Milklines Milk inlets from each cluster should enter the upper third of the milkline. The recommended system vacuum level depends mainly on the height of the milkline above the cow platform.