A job that often gets put on the long finger but which can severely impact cow health and milk quality is the changing of milk liners.
There is a lot happening on dairy farms at the minute, as we are into the middle of the breeding season as well as trying to secure a first cut of silage.
So, often this job can be put off to the point where they have to be changed with urgency after a failed milk quality test from high thermoduric bacteria or after a few cases of mastitis begin to arise in the herd.
The milk liner is the only part of the milking machine that comes into direct contact with the cow, so their condition is vital for milk quality, mastitis control, and milking efficiency.
Liners usually last up to 2,000 milkings or at least six months, and should be changed whichever one comes first.
Liners need to put on the correct way as otherwise, when they are put on to the cow’s teat, they will pinch the teat and cause a lot of discomfort and kicking in the parlour, which upsets the flow of milking as stress levels are up.
I always find that when you are down in the parlour changing liners, it gives you a chance to check up on anything else around the pit or along the milk line. The milk line or pulsation tubes should also be checked at this time to ensure they are not damaged.
Changing milk liners
You need to know the number of cows milking, the number of units in the milking parlour, and the number of milkings/day to calculate how frequently you need to change your liners.
The following calculation as per Animal Health Ireland (AHI) can be used to work out the number of days between linear changes:
For instance, if you are milking 100 cows in a 12-unit milking parlour twice a day, liners should be changed every 120 days.
This means that the liners in this parlour need to be changed at least twice a year in a spring calving herd with a two-month dry period. If this herd started calving at the start of February, liners will have to be changed in the coming few weeks.
Over time, worn liners reduce milking performance and slow down the milking process – which can increase teat end damage and the spread of mastitis-causing bacteria.
As liners wear down, they lose their elasticity, collapse, and take longer to open, but will also close early as they will collapse under vacuum, leading to poor and inefficient milk out.
Bacteria can also build inside the liner where small cracks form. This roughness can tear the skin of the teat and be difficult to clean and disinfect.
Changing liners will also reduce the risk of high levels of thermoduric bacteria in your milk, as thermoduric will survive in perished rubber.
Liners are like tyres on a car, as they play a critical role and are always in motion during milking and also have to withstand the effects of cleaning agents and high temperatures.
So, it is advised for farmers to get their liners ordered and in the yard so, when things do calm down, they are at hand to be changed come a wet morning or afternoon.
