Skip to main content
Pulsation and Vacuum: what could happen if we don’t ally with them? Part - 1

Pulsation and Vacuum: what could happen if we don’t ally with them? Part - 1

In the previous issue we highlighted the value of a reliable vacuum and pulsation system for an undisturbed and respectful milk extraction. On the two following blog episodes, we will investigate what could be the aftermath of an incorrect vacuum pulsation on animals’ well-being and milking performance.


If you have already been implementing the procedures we advised in the previous episode, or you decided to start following our tips after discovering them, you are on the right track.

If, instead, you chose to ignore the insight provided by our experts, be careful! Wrong vacuum pulsation could undermine milking system functioning, leading to serious consequences for your animals, your milking performance, and your milk quality, as demonstrated by the following cases.


Vacuum drops and irregular vacuum fluctuations

During milk extraction, teat-end vacuum undergoes many changes, which determine cyclic vacuum fluctuations, indispensable for a smooth process and for preserving teat health.


Figure 1 - Correct pulsation cycle with regular vacuum changes.

Source: milkrite | InterPuls internal training material


Nevertheless, due to an inappropriate capacity of the vacuum pump, small diameter of vacuum lines, or inappropriate milking components, some undesired vacuum changes might take place, as our expert Filippo Lusetti highlighted:


If vacuum reserve in the pump is not sufficient, the system may not be able to cope with sudden vacuum drops or fluctuations, due to falling clusters or a malfunctioning shut-off valve.

Hence, the vacuum would be dramatically reduced, and milking performance would worsen, causing stress to animals.

Lower vacuum determines lower peak milk flow rate, longer milking time and higher stripping, making it easier for bacteria to enter the mammary system. More specifically, a dramatic vacuum drop could provoke the flooding of the liner, followed by the reflux of milk from the teat into the gland cistern. Depending on the capacity and flow characteristics of the claw, bacteria might also spread from an infected quarter to uninfected ones.”


As these words anticipate, the main undesired vacuum changes are:


  • Vacuum drops. They take place as the milk flow starts to be transported through milk tubes. Factors that could increase the drop of teat-end vacuum are high milk flows, especially in highline milk transport systems when not properly set up, and insufficient or blocked air inlets in the claw.


  • Irregular vacuum fluctuations. These consist of an excessive decline and consequent recovery of vacuum levels within a milking unit, due to a liner slip or cluster fall, which cause unexpected air entrance into the vacuum system.

Some factors that worsen irregular vacuum fluctuations could be:

  1. High milk flow rate at the occurrence.

  2. Large quantity and position of sudden air admitted.

  3. Obstruction to air flow.

  4. Small diameter of milk tubes.

  5. Inefficient vacuum regulator.

  6. Reduced capacity of vacuum pump.

Combined with the functional and essential cyclic fluctuations, the irregular ones might prolong milking time and impede proper udder emptying, irritating teat tissue until clinical mastitis (Figure 2).


Figure 2 - Normal teat compared to different mastitis symptoms:

red teats, blue teats, open orifice, and firm red teats with ring at base.

Source milkrite | InterPuls internal training material


To show the key role played by good quality components in avoiding irregular fluctuations, the case reported by Luca Giuliani, another of our experts, could be emblematic.


“A farmer reached out to us, after noticing that his cows were unexpectedly restless during milking and mastitis cases spread among the herd.

The reason beneath turned out to be a malfunctioning and worn valve, which generated irregular vacuum fluctuations, deeply affecting the milking process and, consequently, cows’ udder health.

Once we replaced the old valve with a new and efficient vacuum regulator, milk extraction was restored, and infections dramatically decreased.


We hope these cases, enhanced by our experts’ insight, drew your attention not only to the importance of vacuum pulsation but also to how underestimating system maintenance could be the worst choice for your farm efficiency.

However, these were only a few of the side effects of bad vacuum pulsation. Don’t miss the next episode to find out more!


milkrite | InterPuls thanks their experts Filippo Lusetti and Luca Giuliani for their meaningful contribution.




  • Dynamics of teat-end vacuum during machine milking: types, causes and impacts on teat condition and udder health – a literature review Besier, Lind, Bruckmaier - Journal of Applied Animal Research, 5/2015, 44:1, 263-272

Full article: Dynamics of teat-end vacuum during machine milking: types, causes and impacts on teat condition and udder health – a literature review (


  • Internal training material – milkrite | InterPuls