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High maintenance - thorough annual service is essential for optimum milking machine performance



Maintenance is essential

Maintenance is essential

Milking machines should be tested at least once annually

Milking machines should be tested at least once annually


Maintenance is essential

The best laid plans in dairying, not to mention considerable financial investment, can unravel if your milking machine is prone to breakdowns.

For that reason, it's essential to have milking machines serviced and tested by an IMQCS (Irish Milk Quality Co-operative Society) registered milking machine technician at least once per year.

With calving still over a month away for most dairy farmers, now is the ideal time to service your milking machine.

A list of registered milking machine technicians is available on


Milking machines should be tested at least once annually

Milking machines should be tested at least once annually

Milking machines should be tested at least once annually

Thorough servicing will ensure the machine will work well and generally without any breakdowns.

The milking machine should be tested at least once annually. After servicing your milking machine the technician must test the machine, write the results on a test report form, list any faults and recommendations and leave you a copy.

The technician must look over the results to see that all readings from the test are within limits.

Test results on the report should show that the vacuum gauge is accurate, the vacuum level is correct, the pulsation system is working properly, there is sufficient vacuum reserve and that there are no unnecessary or excessive air leaks.

The test report is proof that the machine is performing correctly after being serviced. It may be needed for quality assurance purposes also.

Spare parts

A good supply of spare parts will come in handy throughout the year.

Spare sets of liners, short pulse tubes, claw bowels and claw seal kits, vacuum pump oil, v-belts, etc, will be needed from time to time.

Having parts to hand will mean that anything that goes wrong can be sorted straight away as opposed to struggling along, for perhaps weeks without them.

Liner change interval

Research indicates that liners should be changed after about 2,000 cow milkings. Worn liners are not able to milk out cows fully and milking speed will be slower.

They also increase teat end damage and the spread of mastitis bacteria.

Calculate the recommended liner change interval for your machine, e.g. a 10 unit plant milking 80 cows will milk 8 rows twice a day ie 16 milkings per liner per day therefore change the liners every 125 days (2000/16) or about twice a year in this case.

When liners are being changed cut a few liners lengthways for any signs of wear inside the barrel, especially if the change interval is longer than recommended.

Ensure that liners do not leak when fitted in the shell and that they cannot twist easily.

The barrel of the liner is stretched between 5 and about 15pc of its original length when fitted in the shell.

With this stretching the barrel will lose its tension over time as can be seen when you place a new liner beside a worn one; the worn liner is always longer.

It is not a good idea to replace liners just before drying off as they are left under tension during the dry period.

Claw bowels and seal kits

Check claw seal kits and replace as necessary. Shut-off valves that don't seal properly at cluster take-off can cause clinical mastitis and raise cell counts.

It is also much more difficult to attach and detach a cluster that needs a new seal kit or has a cracked bowel.

Claw seal kit replacement is often neglected at servicing. I have seen gaskets that are not seated properly under bowels and ones that have swelled up because they are long overdue a change.

Chipped or cracked claw bowels should be replaced. I have found that some spurious bowels don't fit correctly so that they don't seal fully on their gaskets.

The claw air admission hole should be above the milk in the bowel during milking.

The admission hole can be in the bowel or in the claw piece.

There is a danger when using spurious or different versions of bowels that one could end up with none or even two claw air admission holes on a cluster.

On-going checking and maintenance

While the milking machine technician will carry out the main servicing and test the milking machine there are checks that you should do yourself daily and from time to time. These include:

  • Check filters on vacuum regulator regularly and clean or replace as necessary. They can be cleaned by washing in warm water and mild detergent. Dry by squeezing in a dry cloth
  • Listen for the sound of air hissing through the regulator during milking. It is normal to hear air being admitted to the regulator. If air cannot be heard, it may be that the machine is leaking air. However, if a variable speed drive is fitted, the regulator should not be regularly admitting air
  • Check vacuum level on the vacuum gauge daily
  • Don't delay in replacing any liners and short pulse tubes with holes. Have spares parts to hand. Dirt and water will be sucked into short pulse tubes if tubes with holes are not replaced promptly
  • Ensure no water, birds or vermin can enter the air supply pipe to the pulsators. The breather line bringing air for the pulsation system should have an inlet filter(s) to ensure the air is dust free. The filter lowers the noise from the pulsation as well. These filters are located in the milking parlour. The breather pipe often takes its air from outside the parlour. This is fine as long as there is some sort of mesh on the pipe inlet to prevent small birds getting into the pipe. They can die inside the pipe and interfere with the air supply to one or more pulsators. The pipe inlet should also be turned downwards so that the possibility of water from an overflowing gutter can't enter it.
  • Check vacuum pump oil regularly, top up reservoir and adjust oil drop rate if necessary
  • Check that claw air bleed holes are free daily. One of the causes of liner slips and cluster fall-offs can be due to blocked claw air admission holes
  • The pulsation airline should always have a drain valve at its lowest point. Check that it is sealed during milking and free to drain out any liquid when machine is turned off. The airline should slope towards the drain valve
  • Check that there is an even and continuous fall on the milkline. The slope should be at least 1:100 (1pc) and preferably 1:67 (1.5pc). There should be a similar slope on the pulsation airline
  • Inspect all rubberware for cracks and wear regularly. If your fingers get blackened from the inside of rubber milk tubes it's a sign that it is overdue a change and or harsh or incorrect cleaning methods may have been used. Flattening of the milk tube near the cluster can be caused by kinking of the tube to shut off the vacuum at cluster take off.
  • Avoid loops in the long milk and pulse tubes. Milk tube loops lower vacuum at the teat end and slow down milking.
  • Check that the wash solution/rinse water flows freely in all clusters during machine washing. Check the jetters for signs of dirt or milk residue which can spread infection. Brush wash occasionally if necessary.
  • Check that teat sprayer nozzles are forming a full cone shaped pattern and that valves are not sticking and valves and joints are not leaking.

Tom Ryan is a retired Teagasc farm buildings and dairy infrastructure specialist

Indo Farming