Clean equipment counts

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Clean Equipment Counts

By Gary Bennett, DVM

It has often been said, both here in Northeast DairyBusiness and elsewhere, that clean, comfortable cows produce more high-quality milk. How that milk is handled after it leaves the cow and how well milk-contact surfaces are cleaned are also critical to delivering a premium product to consumers. Milk quality scores, specifically, the various bacteria counts, indicate just how well this is being accomplished on each dairy. Following up on the Bulk Tank Monitoring Program initiated in 2004, QMPS is now preparing to offer milking system cleaning analysis based on NMC (formerly the National Mastitis Council) guidelines.

Plan well, plan ahead

With the trend to larger milking facilities with more units, meters and larger line sizes, proper cleaning of the complete milking system has become the most complicated part of planning a new installation. The time to place a second air injector on the “add water” line is in the beginning, not after repeatedly tearing a system apart to find the cause of a high Lab Pasteurized Count.

During the planning phase, it’s critical for dairy producers to hire an equipment installer who has their trust. Owners must have the confidence that the installer’s recommendations are necessary, not just an effort to “pad the bill” or “have the low bid” on a new facility.

Producers should make their long-range plans clear to their equipment installer during the planning stage. Plans to increase herd size eventually may require more units and larger tanks and lines. Draw on your installer’s experience to build some flexibility into the system and save yourself the additional cost and inconvenience of retrofitting additional components. Milking a herd on one side of a parlor while you increase the number of stalls on the other is no fun.

As milking systems have become larger, they’ve also become more complex. At one time recording thermometers were all you had to document whether systems were functioning properly. Now, computers are used to monitor all aspects of system cleaning.

Dealers are normally very good about leaving laminated copies of the washing instructions for a system, including water temperatures and cycle length, water hardness values and other factors. It’s a good idea to file a paper copy of the instructions in case the laminates are “misplaced.”

Keep in mind these instructions are product specific and apply to the particular cleaning products and water hardness used at the time. You should check water hardness seasonally, and provide new instructions with any cleaning product change.

NMC guidelines

Just as it did to prepare a scheme for producers to follow to evaluate their systems’ milking function, the NMC collaborated with dairy industry experts to develop guidelines that cover milking system cleaning. The comprehensive guidelines provide a step-by-step plan to investigate cleaning problems. NMC also provides templates to follow and fill in with the various readings.

Recommended temperatures (Table 1) and cycle lengths (Table 2) are two examples of the information available. While beginning temperatures are important to evaluate hot water capacity and settings, discharge temperatures can also be critical, especially here in the Northeast where winter (and sometimes fall and spring!) temperatures can rob heat from the exposed surfaces.

Likewise, you should note pH values of discharge solutions to assure that the alkaline wash and acid rinse are, in fact, what they’re supposed to be. Initial rinse water should return clear to ensure that all milk has been flushed from the milklines prior to adding the hot alkaline wash solution.

The NMC Guide also suggests strategic sampling techniques to pinpoint a problem in a particular section of the system or a specific group of cows or milkers. It also provides techniques to help pinpoint an incubation problem due to overuse of milk filters.

Most of these checks don’t require sophisticated test equipment or expensive supplies. A stopwatch, pH paper and accurate thermometer, along with careful observation of claws, meters, sinks and fill lines (Is any air being sucked into the system at the end of a cycle?), can solve many cleaning problems.

Producers can use a stopwatch, pH indicator paper and thermometer to gather information about milking system washing.

While the hot water, detergents and acid rinses are what clean a system, the slug of water formed by controlled air admission into the system is what puts these solutions in contact with all of its surfaces.

Analysis of slug formation and movement through the lines is arguably the most complex part of system troubleshooting. Many different pieces of equipment can be used for this purpose. QMPS personnel are being trained, and getting the necessary supplies, to provide these services along with their current culture and equipment analysis.

A case report

A 350-cow dairy had a problem. Its somatic cell count (SCC) was consistently below 250,000. Most of the time its bacteria counts were acceptable but once or twice a month, counts would spike.

The high Lab Pasteurized Count indicated a cleaning problem, but there was no pattern to the problem: Milk from either tank, any milker and on any day could be high. Adequate hot water was available, and all chemicals were in the proper concentrations.

Strategic samples were likewise not helpful. A visual inspection of the system, including dismantling lines where possible, didn’t reveal any problems.

There was just one thing left – the plate cooler. The last thing anyone wanted to do was tear that apart and try to get it back together. QMPS had an idea. Why not bypass the plate cooler for a few pickups and see what happened. We were disappointed when the counts followed the same pattern.

Plate coolers may be bypassed to evaluate their effect on bacteria counts.

Then QMPS decided to check water temperatures one more time and as luck would have it, the timing was right. It turned out that the hauler came in early that day and helped out by hooking up the tank washer just as employees were finishing milking. Washing the tank took enough hot water so the wash cycle was only operating at 110 degrees. This herd solved its occasional high Lab Pasteurized Count problem by asking the hauler just to rinse the tank and let the milkers set up the tank washer.

Table 1.

Suggested water temperatures for various system washing cycles


Temperature/degrees F

Rinse water


Wash water


Wash dump

> 120

Acid rinse

90 – 110

Premilking (next) sanitize:

Follow label directions

Table 2.

Washing cycle lengths and system pH




3 – 5


6 – 10 (7- 8 circulating)

Acid rinse

4 – 6

Wash solution pH


Acid rinse pH

< 3*

Premilking (next) sanitize: Time and concentration vary according to product used.

* pH readings are taken at end of cycle as system drains.


Article reprinted with permission from Northeast DairyBusiness, June 2005.


Quality Milk Production Services

Northern Laboratory
SUNY Canton
Canton, NY 13619
(fax) 315-379-3931
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240 Farrier Road
Ithaca, NY 14853
(fax) 607-253-4000
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36 Center St, STE A
Warsaw, NY 14569
1-877-645-5525 toll free
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111 Schenectady Ave.
Cobleskill, NY 12043
(fax) 518-255-5682