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Annual milking machine testing on the way
Faults like vacuum leaks and excessive component consumption which effectively reduce the “reserve air” and can create vacuum instability and cup slip, can only be detected and located by air flow analysis at a plant test.

Annual milking machine testing on the way

Tim McVeagh

NZCP1 is the Primary Indistries Ministry’s operational code for the design and operation of farm dairies. The latest revision, form December 1, 2015, includes requirements for milking machine performance and maintenance. What does this mean in lay terms?

Milking machines must be tested by a registered milking machine tester at least once a season or at the frequency specified in writing by the tester. The tester must have a practising certificate and test the plant according to the New Zealand Milking Machine Testing Standards.

“This has been accepted by the industry as being best practice,” Murray Pedley of Quality Consultants of New Zealand (QCONZ) said.

“As with many new requirements it will be a soft entry initially but each dairy company will decide how they will enforce this as part of their dairy assessment protocol”.

Electronic pulsators, more modern vacuum pumps and milk pumps, and higher installation standards mean breakdowns and faults detected at testing are now less common. However, in terms of running times, we expect much more of our milking plant these days. Our cars too are now more reliable, (and do higher kilometres), but that doesn’t mean servicing should be ignored.

Dairy NZ recommend not to rely on an annual test and service, but this should be done twice a year. Where milking times are extended or milking is year-round, a lot can happen in terms of wear and tear. The frequency of testing milking plants in NZ is variable and ranges from six-monthly to once “every few years”. Where testing and therefore maintenance has not been kept up, a range of faults is usually detected.

Where maintenance has been slack, breakdowns, often due to the likes of belts or couplings failing, are more common. In extreme cases components like vacuum pumps and diaphragm milk pumps can run out of oil and a costly repair bill exceeds the cost of a test/service visit.  

These often include those which cannot be detected by the farmer, like air leaks, pulsation faults and leaking milk pump seals. And where maintenance has been slack, breakdowns, often due to the likes of belts or couplings failing, are more common. In extreme cases components like vacuum pumps and diaphragm milk pumps can run out of oil and a costly repair bill exceeds the cost of a test/service visit.

A lot of analysis of milking machine faults has been carried out in recent years.

Murray Eddington of Matamata Veterinary Services documented faults found at 100 plant tests between May and December 1998. He found:

  • Only 9% of these were up to the required standard;
  • 49% had perished rubberware which can contribute to air leaks, slow milking out, and undermilking;
  • 45% of all pulsators tested did not meet standards.
  • The milk line and pulsator air line were defect contributors.

Joe, Cranefield, Hodge and Clarke documented milking vacuum and liner compatibility for 200 Waipa and South Canterbury farms which were experiencing a mastitis problem in 2008 and 2009 and 32% had high milking vacuum and 42% had unsuitable liners. Both of these faults are checked at a machine test.

The effect of pulsation on cell count and mastitis is well recognised. Major pulsation faults are often picked up by milkers, but only electronic measurement as part of a full plant test will determine whether pulsators’ ratios and rates are in spec.


When the annual QCONZ or AsureQuality dairy inspection is carried out, the latest milking machine test will be checked to see when it was done and if faults detected have been rectified. A copy of the Farm Dairy Assessment Report is passed on to the appropriate dairy company. It is the farmer’s responsibility to rectify any faults with the milking machine.

While QCONZ consider a “soft entry” may be appropriate as farmers accept this, and as milking machine technicians take on the extra workload, the dairy companies are generally very supportive.

“This is a requirement under NZCP1 that we have to follow and enforce,” Fonterra’s Roger Andela said. “We have a protocol in place and have already included this in the farm dairy assessment, with QCONZ and AsureQuality doing farmer education and monitoring compliance.

“We have to bring everyone on board through education. A big part of this is by promoting the animal health and welfare benefits of having the plant in good order. We see benefits in animal health considerations like teat care and mastitis management, as well as overall milk quality.”

Many farmers schedule their milking plant test and service in winter, but this is the busiest time for milking machine technicians doing plant installations and work like cluster removal installation, seen here. The plant test and service, unlike major plant alterations, can be done any time of year.

Open Country’s John  Fairweather said: “The NZCP1 requirement is simply good management and is based on having a functional milking plant which does not damage the milk, can be cleaned well, and looks after the welfare of the cow by being gentle on the udder during milk harvesting.

“We have discussed this with our suppliers and have not received any resistance. Next season, where farmers have not followed through with a machine test, a return visit after three months is being considered.”

Westland Milk Products’ Andrew Simson said: “We have been following this process for two to three years, so don’t see any major changes are needed. It is followed up formally through the audit programme.”

Synlait’s David Williams said: “If the farmer is not getting a plant check done annually, then he is advised that the system has changed and a plant check should be booked annually.

“A decision has not been made on what action will be taken next season, but it will probably be taken a step further as it is a requirement under NZCP1. What gives us quite a bit of confidence is that we have almost completed our assessments for this season and there are only a very few suppliers who are not getting their plant tested annually.”

Oceania Dairy’s Shane Lodge said: “We will do it in the way that the Dairy Industry Technical Advisory Group recommends. We will let farmers know about it, and get our assessors to determine how many farms comply, and those who don’t comply.

“Oceania will explain to farmers that this is a requirement of the Code of Practice and we expect these requirements to be met. If a farm was having a grading problem, especially somatic cell count, then a firmer stand might be taken, but those farms should have had a plant check in order to rectify this anyway.

“Most of our 67 suppliers would already meet this requirement. With an average herd size of about 800 cows our suppliers tend to place more emphasis on preventative maintenance”.

Testing alone won’t fix a thing

Just as a warrant of fitness check won’t make your vehicle run better or last longer, the standard milking machine test alone won’t drop the cell count, reduce the incidence of clinical mastitis, reduce milking time, increase yield, or increase the life and reliability of the plant.

This is because the test itself does not rectify faults, which if fixed may have some of these desired effects.

Having said that, many testers tighten unions and eliminate obvious leaks before testing, so the test may not be carried out on the plant as found and some improvement (in reserve air) may be gained while testing. Milk line unions on rotary installations, for example, are common culprits for working loose.

Farmers may engage an independent tester if they consider them to be selling only good practice. Faults detected then need to be rectified separately by themselves or a milking machine technician. Alternatively, well-equipped milking machine technicians, knowing the componentry in the dairy, will be able to test and carry out basic repairs at the one visit, keeping the cost of service and repairs down.

The winter dry period is the silly season for milking machine companies, with full plant installations and major dairy alterations having to be completed before calving. This work may be delayed by behind-schedule building, painting, or electrical work which must be completed first.

Many farmers have their plant tested in winter as part of the winter maintenance programme. An annual plant test and service however can be carried out at any time during the milking season. Prompt service and associated repairs are more likely, and the winter workload for milking machine technicians will be eased.