Dairy Herd Information
Milking Machine Liner Replacement
Teatcup liners are the sole part of the milking plant which actually comes into contact with the cow, and their condition and maintenance is critical in mastitis control and efficient milking.
Liners have an effective limited life, generally quoted at 2,500 milkings for rubber-based liners and 10,000 for the more expensive silicone-based variety. However, many factors can affect the lifespan of liners and it is essential that they are checked for condition frequently; it is not unknown for defective liners to fail at a relatively early point in their quoted lifespan.
A liner must be designed specifically to fit the teatcup shell for which it is intended, which should ensure that it is of sufficient length to collapse fully around the teat base and allow proper blood circulation in order to avoid teat damage.
Due to their function, liners have a large degree of elasticity to enable them to open and close around the teat. However, due to wear and tear they will eventually loose elasticity and their circular profile – becoming collapsed – due to opening and closing continuously in the same plane. When this change in working profile occurs, the liner takes longer to open, and does not close as crisply, lengthening the time needed to milk and potentially causing teat damage.
Liners are also damaged by chlorine and other chemicals used in milk production, which denatures and weakens the rubber-based liners in particular, leading to roughness, perishing and splitting. When the interior of the liner becomes rough, it can become more difficult to clean and disinfect and can harbour pathogens, leading to increased potential of cross-contamination between cows, and can also increase Bactoscan readings.
Most liners are packaged with similar information enabling easy calculation of their expected lifespan, but a simple formula exists to check liner usage in terms of number of milkings:
Number of cows in herd x number of times milked per day x liner life in days
number of milking units