Mastitis | Milking machine care

Regularly checking your milking machine

Regular checks will help ensure that the speed and completeness of milking is maintained, and the risk of mastitis due to milking machine faults is reduced. Problems are often due to inadequate maintenance of mechanical components and rubberware, so keep a regular check list and maintenance routine in place.

If more than one person milks in your dairy, it is important to assign these checks to specific people and ensure that the right person is alerted to any problems that are found or suspected. Daily and weekly checks should be conducted by milking staff as part of their regular list of responsibilities. Monthly checks should be done by the herd owner, manager or other skilled observer. Recording the results of monthly checks enables subtle changes due to wear and age to be detected more easily.

Daily checks

Read the vacuum gauge. Check to see that the needle reaches the red line (or a line that you may have drawn on the dial). If the reading is different to normal, tap on the gauge to ensure that the needle isn’t sticking. If sticking, or vacuum levels are of concern, contact your milking machine technician. See here for typical vacuum levels recommendations.

Listen to pulsators. The sound of air entering the external air inlet should be regular and intermittent. It should be the same sound for all pulsators.

Observe cows during milking. Unsettled cows may indicate a problem with the environment, or milking machine.

Check that claw bowl is not flooding during milk flow. If flooding, the air admission hole or vent is likely to be blocked. This can lead to more cup slip, slow or incomplete milking, and difficulty removing clusters even after the vacuum is cut off. Remove any debris with the probe designed for the task - avoid using drill bits or other tools that may enlarge the holes.

Check milk is entering the receiver can and flowing in smoothly.

Check teats as the cups come off for any colour changes - reddish, bluish or purplish skin colour swelling, hardness at the top, middle or tip of the teats.

Check that cows are milking out properly. Split liners, holes in the pulse tubes, short milk tubes, or faulty pulsators affect pulsation and milk out.

Check if jetters are distorting the liner mouthpiece. Nozzle-type jetters can distort the mouthpiece. Remove teat cups from the jetters immediately after every wash.

Mastitis Machine Care Daily Checks 1000X750

Weekly and monthly checks

Weekly checks

Check rubberware (liners, short milk tubes, pulse tubes etc.) for holes or splits. Damaged liners and pulse tubes will affect milking out.
Check for twisted liners. Align marks/arrows on mouthpiece and short milk tube, or place your thumb in each liner.
Check filter(s) on pulsators and/or filtered airlines, especially when meal feeders are present in the dairy.
Check drain valves on pulsation airline. If milk is found in the drain line, look for split liner(s).
Listen to the regulator. It is normal to hear air being admitted to the regulator. If air cannot be heard, it may indicate that the machine is leaking air. However, if a variable speed drive is fitted, the regulator should not be regularly admitting air.
Check filters on the vacuum regulator and clean or replace.
Check oil level and oil drop rate if the vacuum pump is oil cooled. Check water levels and flow rates if vacuum pump is water-cooled.
Check teat ends for cracks or sores. As a rule, take action if more than 5% of cows have teat end sores or cracks.

Monthly checks

Check effective reserve and regulator function

Effective reserve is an airflow measurement of the spare or reserve pump capacity that is available to maintain stability of the receiver vacuum when extra air enters the system during milking. All systems should be able to accommodate 1 milking unit falling off (2 units in systems with more than 32 bails).

A simple test to try when the machine is running, is to open 1 set of cups (or 2 sets if more than 32 units). If the vacuum drops more than 2 kPa, then effective reserve is not adequate. Call your milking machine technician. Cup slip during cup attachment or when cups are kicked off will also indicate poor vacuum reserve. Variable speed drives, when poorly adjusted, may cause similar problems.

Check for rubberware that has perished or outside manufacturer's guidelines

Cracked and perished rubberware is harder to keep clean and may cause a downgrade in milk quality. Distortions of the mouthpiece lip can affect milking and washing processes.

Check if level of cup squawks and slips requiring correction has noticeably increased.

A running tally over 15 minutes of milking provides a useful measure. Exclude cows with very poor udder conformation that always have cups slip. Note: Preferred machine function - no more than five slips per 100 cows. Machine requires service - more than 10 slips per 100 cows.

Check completeness of milking i.e. under-milking and milking times.

Guidelines to assess complete milk-out:

Record milk-out as	Qualitative checks	Semi-quantitative checks (hand-strip individual quarters)
G (Good)	Quarter is visibly wrinkled.	5 or fewer easy strips equating to less than 50ml per quarter.
P (Poor)	Quarter appears slightly plump, possibly indicating unharvested milk.	10 or more easy strips equating to more than about 100ml per quarter.
U (Uneven)	One particular quarter appears plumper and less wrinkled, relative to the other quarters.

Technote 6 provides more technical information on:

The process of removing milk by machine.
Milking-time tests of machine function.
Measuring completeness of milk out.
Principles of liner selection.

Servicing your milking machine

Regular servicing of your milking machine will help ensure that the speed and completeness of milking is maintained, and the risk of mastitis due to machine faults is minimised. Fully test and service your milking machine twice per year. Ensure that the technician provides and explains a full written report and advises which recommendations are: Urgent and require immediate action, important but not urgent and which are ideal or cosmetic changes.

Use a milking machine technician who tests to NZMPTA standards. Make sure your technician performs tests according to NZMPTA (NZ Milking & Pumping Trade Association) standards.

Confirm this before making the booking; the technician should have a current NZMPTA certification. A full list of current certified technicians can be found online.

There are 5 different types of tests that most milking machine testers can undertake:

Physical measurements
Dry tests
Wet tests
Milking-time tests
Cleaning-time tests

Technote 25 provides technical information for farmers and advisers on:

The findings the technician's report should include.
The most cost-effective sequence for upgrading inadequate components.

Mastitis Milking Machine Care Rotary Image 1500X1000

Related causes of contamination

Bacteria are spread by milkers’ hands, teat cup liners, cross flow of milk between teat cups, and splashes or aerosols of milk that occur during stripping.

Keep your hands and the milking area under the cows as free as possible from dirt and contaminated milk to reduce the transfer of bacteria. Do not use high pressure hoses directly beneath or around cows, as these can create aerosols of bacteria-laden droplets that form and settle onto cows.

Clinical cases and chronically infected cows are a source of infection for healthy cows. If these mastitis cows are milked last, the risk of spreading infection is significantly reduced.

Technote 8 provides technical information on types of gloves available (nitrile, latex, rubber), Cluster flushing systems, the value of segregating high SCC cows.