Pre-treatment Time, Tips & Tricks

To prepare the cow for milking and let her fully participate in the milking process, pre-treatment of the cow is important for good milking performance. Pre-treatment on the Lely Astronaut is done with pre-treatment brushes. The pre-treatment brushes have a dual function: they clean the teats and stimulate milk flow from the alveoli. Clean teats result in hygienic milking by removing dirt, manure, bedding material, udder care residues, and bacteria from the teats and lower udder. Sufficient stimulation and lag time ensure a good start of the milking process by preventing bimodality. As a result, the pre-treatment concept contributes to clean, comfortable, and complete milking. In this article, settings that influence pre-treatment time are covered.

Bimodality & lag time

Bimodality is a drop in milk flow after milking has started. This is caused by removal of cisternal milk from the udder, while milk ejection from the alveoli has not yet started because it takes some time for oxytocin to cross the critical threshold for milk letdown from the alveoli, see Figures 1 and 2. The time between prestimulation and the onset of milk ejection from the alveoli is called the latent period, or 'lag time'.

Figure 1. Example of a good start of the milking due to sufficient lag time

Figure 2. Example of a bimodal milking

A bimodal milk flow occurs when:

• a cow is milked with low udder fill;

• a cow is milked too early, e.g. within 6 hours from the previous milking;

• the pre-treatment stimulus is not sufficient;

• the teat cups are attached too early.

  

  Figure 3. Example of short intervals & low udder fill

  During the bimodal phase, milk flow is low and therefore inefficient. In addition, the teat is exposed to the full system vacuum, which can be uncomfortable for the cow and results in congestion of the teat, see Figure 4. This can also pose a potential risk for teat damage, low milk speed, prolonged cups-on-time, and incomplete milkings, compromising milking performance and robot capacity.

The amount of stimulation and lag time required is influenced by duration and strength of the stimulus, the extent of udder filling and circumstances during milking. Research and milk quality experts advise at least 60-90 seconds between first contact with the udder and connecting the first teat cup (GD, 2017). More specifically, during 2x daily milking with sufficient udder fill, bimodality can often be successfully prevented with 60 seconds of lag time between first touch and attachment, while for 3x daily milking it is advised to aim towards 90 seconds between stimulation and attachment (Bruckmaier, 2001). More frequent milking per day or shorter intervals may require longer lag times (by extending pre-treatment time) to prevent bimodality.

Figure 4. Teat congestion

Horizon settings

Several settings influence the duration of pre-treatment, and thus directly influence lag time. For sufficient lag time, the recommendation is at least 2x4 seconds on the Astronaut A3 and A4. To accommodate milk secretion at the A5, the recommendation is at least 2x4 seconds, since the A5 attaches the teat cups more accurately. Combined with a good connection performance, those settings result in a lag time (pre-treatment time + connection time) of around 80-90 seconds. This can be shorter than the 90 seconds we aim for with 3x daily milkings, especially when connection time is good and lower than 20 seconds. In some cases, however, we see that a lag time of 110–120 seconds is necessary to fully optimize milk letdown. We’ve become very efficient at attaching the cups, so it’s important to ensure we’re doing what’s right for that quarter and that specific cow.

All of this data can be viewed in the backend by your FMS advisor. Ask them what the lag time is on your farm and whether bimodal milkings are within an acceptable range.

Tip: For 3-teated cows, it can be beneficial to manually set longer pre-treatment settings for individual cows to realize sufficient lag time for 3-teated cows.

Pre-treatment time on herd level below 52 seconds is not advised since there is a strong relation between increased bimodality incidence on herd level and a short pre-treatment time. Pre-treatment settings of e.g. 1x5 seconds, 2x2 seconds, or shorter result in pre-treatment times below 52 seconds.

¹ Median, the ‘middle’ value of a data set, separating the higher / lower half of the data distribution. ² Note that the average is higher than the median, indicating that poorer performing robots have a big impact on the average.

E-link settings

Besides the Horizon settings on pre-treatment, other settings on the E-link influence pre-treatment performance as well. Those settings are e.g. USA-pretreatment, brush height & position, and X-movement during pre-treatment.

• USA-pretreatment settings are covered in this article.

• Data shows that some Astronaut A5 robots still have incorrect settings for “X movement during pretreatment”. For optimal pre-treatment Lely recommends using 50 mm (about 1.97 in) as standard setting for A5. Do not use a value lower than the default of 15 mm since this might affect pre-treatment time.

• This video shows how to set brush height & position for effective prestimulation.

Figure 5. Screenshots of E-link and Horizon settings

Wrap up

Several parameters influence bimodality incidence, of which too short milking intervals and low udder fill (e.g. due to milkings within 6 hours) or a pre-treatment time below 52 seconds are major contributors. Besides the obvious Horizon or E-link settings on pre-treatment time or duration, pre-treatment performance can be influenced when setting X-movement below default. For 3-teated cows, it can be beneficial to set individual pre-treatment settings, to accommodate for sufficient lag time.

For more insight into milking performance, we also encourage you to read our blog post, How to Evaluate Completeness of Milking, to support your milking management strategy. Additionally, this article on delayed letdown and its impact on returns provides valuable context on why optimizing lag time matters: Delayed Letdown Equates to Diminished Returns.