While most farmers will rightly opt to get milking machines serviced before cows begin to calve, it is important that they continue to check the machine throughout the year to ensure its efficient running.

Francis Quigley, milking machine specialist with Teagasc, talked through some of the key areas for farmers to look out for when the Irish Farmers Journal met him at Kildalton Agricultural College’s impressive milking machine training facility.

“We have seen with expansion that many farmers will now be putting 13 or 14 rows through the parlour or in some cases even more. That can be hard on the farmer and the cow,” Francis explains.

Franic Quigley, Teagasc milking machine specialist (left) and Tim Ashbourne, college principal.

“When a farmer is spending that long in the pit milking, to spend another few minutes checking milking machines is the last thing they want to do but it is vital to ensure the machine is running efficiently.”

Daily checks

When it comes to checks that should be carried out daily, the vacuum pump is critical, as Francis explains: “It is important to have the vacuum gauge that is somewhere visible in the pit. For a midline plant it should be running at 47kPa to 48kPa. This decreases to between 42kPa and 45kPA for a low-line plant.

“The gauges are one indicator if things are going right.”

It is also important to see that the needle on the gauge reads the same at every milking, that it aligns with the red pointer during milking and reads zero when the machine is off. Check to ensure that the needle is not sticking.

Another area to check daily are the air vents on the cluster. According to Francis, these small air vents will take in six to eight litres of air per minute, while milking is occurring. “These can very easily get blocked with muck or dirt and should be checked regularly. One sign that they may be blocked is if the bowl on the cluster is flooding, or if the milk is surging.”

Effective reserve

It is important that your vacuum pump has sufficient capacity for the plant. In general, one vacuum pump can do up to 14 to 15 units but, again, it depends on the capacity of the pump. Larger milk and vacuum lines on modern parlours require will require more vacuum capacity.

“The vacuum pump has to have the capacity to maintain the correct vacuum level or you will have issues with slow milking and cows not being fully milked out. It is not just the capacity of the pump, but the effective reserve capacity for milking must also be adequate,” Francis says. This could be reduced if there are leaks somewhere within the equipment.

During milking, if a cluster falls off, the vacuum should be able to compensate. This is known as the effective reserve and it ensures that there is still enough vacuum to ensure cows are milked out. If there is not enough effective reserve capacity, then pressure will be reduced and it can lead to cows being undermilked.

All milking machines should have enough reserve to cover the possibility of at least one milking unit falling off and for larger systems, it should have enough effective reserve to cope with two units falling off.

These incidences, in particular, show the advantage of variable speed vacuums. If a cluster falls off, the variable speed pump will automatically increase to keep the pressure stable.

Variable speed vacuum pumps can automatically increase to cope with a cluster being kicked off.

This ensures that air is not being sucked in by the vacuum unless it is needed, reducing energy usage. For a standard vacuum the plant will run at the standard speed for the duration of milking which needs to incorporate the effective reserve.

One simple test that can be carried out is when the machine is running open one set of clusters, if the vacuum drops more than 2kPa, then the effective reserve is not adequate.

“It is also important that the vacuum regulator is working. Listen and see if air is being drawn in through it,” Francis says. “The hiss of air entering the regulator should be greatly reduced when the clusters are open. Check the filter regularly and clean, if necessary.”

If milk is coming into the collection jar in slugs, it also indicates that there may be issues with the vacuum or the width of the milk line itself, among other issues. Slugs in the milkline could reduce the vacuum level at points further down the milk line.

The vacuum regulator’s filter can get dirty preventing air from being drawn in.

Milk liners

Milk liners, in particular, may need to be changed at this time of the year with the recommendation to change liners every 2,000 milkings or every six months, whichever occurs first. Old or damaged milk liners can lead to several issues such as a slower milking speed and cows not being fully milked out. The presence of milk stones in the liners can also lead to damaged teats.

Damaged milk liners which can cause damage to teats.

“The most important piece of the milking machine are the liners. These are the only piece of the machine that will come in contact with the cows every day,” Francis says. “Make sure that there are no cracks or damage on the mouthpiece of the liner.”

Liner condition should be regularly checked. Ensure that liners do not become twisted and align marks/arrows on the mouthpiece and the short milk tube. The liner is designed that when it is fitted it will be stretched 5% to 15% more than its original length and maintain under tension. However, as soon as they are put to use, liners will slowly begin to lose their tension. This will decrease the speed with which they can open and close. As they age they will also absorb fat and hold bacteria.

Once they have deteriorated beyond a certain stage, the speed of milking will be reduced. There can also be issues with undermilking and teat damage.

Pulsation

The pulsation of the machine should also be monitored. Newer machines will generally not have any issues when it comes to pulsation ratio as long as they get a yearly service, but there can be problems with older machines.

“The majority of parlours are working at approximately 60 cycles/minute. One easy way to check if your pulsation rate is correct is to stick your thumb into the mouthpiece of the cluster and count how many pulses there are in a minute,” Francis suggests.

More likely issues with pulsation will be related to the pulsation phases within each cycle. Ensure that the milking machine technician measures the four phases of pulsation known as A, B, C and D as part of the IMQCS test. These represent the different stages of the liner during a pulsation cycle which are opening, open, closing and closed. Clusters are designed to squeeze and cut off vacuum to the teat during each pulsation. This is essential to massage the teat and maintain its blood supply.

“The closed period is also known as the rest period and it is important to prevent damage to teats,” Francis says. “Liners slipping is another area to look out for. If air gets in one side of the of the mouthpiece it can push air and milk back up into another one of the clusters which is one way that clinical mastitis can be spread.”

It is important to ensure that there is an adequate supply of water to the plate cooler. The ration of water to milk is 2:1 to ensure that you are getting the maximum efficiency from the plate cooler.

While farmers have the option of installing a variable speed vacuum pump they can also install a variable speed milk pump. This has the benefit of ensuring a steady flow of milk through the plate cooler which is a much more efficient use of the plate cooler and will also mean it is more effective at cooling the milk.

While undermilking has been highlighted as a concern in certain circumstances if there are issues with the machine or the operator, overmilking can also be an issue, according to Francis.

“If clusters are coming off and the teats are red we have to ask is the vacuum too high? Have the clusters been left on too long?

“With expansion many farmers may have increased the number of units they have but can you manage this increase? Ensure that automatic cluster removers are serviced by the milking technician, and that the take-off settings are correct and that vacuum in the claw is cut off before the rope pulls off the cluster.”

Undermilking

The best way to measure undermilking is by hand-stripping at least 25% of the cows immediately after cluster removal. Then measure the volume of milk from each quarter. According to Animal Health Ireland’s Cellcheck guidelines, undermilking is a problem if more than 20% of the quarters have strip yields of more than 100ml.

It is vital that filters are regularly checked for a build-up of material.

There are other aspects of the milking machine that also need regular attention.

  • Ensure air and vacuum filters are clean. This can be a particular issue where filters are fitted close to feeders.
  • Check the oil level on the vacuum pumps and also ensure that oil is being fed into the machine.
  • Check drain valves on milk lines and pulsation airline.
  • Measure the completeness of milking and milking times.
  • Check liner slips – if there are more than 10 slips per 100 cows, then the machine requires service.
  • Check drain valves on the pulsation airline.

    Calculating liner life

    The life of the liner can be calculated using the following equation:

  • Number of days = (2,000 x number of milking units) / (herd size x number of milkings per day).
  • For example: A 150 cow herd being milked twice per day in a 14-unit swing over parlour would need liners replaced every 93 days or three months. If this was increased to an 18-unit parlour they would only need to be changed every 120 days.

  • (2,000 x 14) / (150 x 2) = 93 days.
  • (2,000 x 18) / (150 x 2) = 120 days.
  • “It is important to time it so that you are not changing liners towards the end of the year as they will be sitting under tension for several months during the dry period and can lose their tension,” Francis said.

    Milking machine training

    “The number of students studying dairy modules has increased significantly over the past few years,” according to Tim Ashmore, college principal.

    “The new milking machine training area has been a great addition to the milking skills training at Kildalton College. The facility incorporates many of the leading milking manufactures including Person, Delaval, and Dairymaster. This allows students to diagnose and operate many machine types all in one centre.” He continued: “Students are taught all the components of the milking machines and how faulty pulsations or vacuum levels can have a detrimental effect on the milking process.”