Seconds Do Matter in Your Milking Routine

In any milking system, whether a parlor or tie-stall set-up, timing is critical in numerous areas. Time is valuable, and time is money! Udder preparations, milking unit on-time, overmilking times, holding area times, parlor throughput, and time spent milking are all interrelated. Timing of any of these can affect cow and udder health, milk production, quality, and employee or owner labor hours. But one of these times can have an overall effect on the entire milking process: the time spent on milking or udder preparation.

Milking preparation serves many purposes: to effectively clean the teat ends, to provide adequate stimulation, and to remove the highest somatic cell count (SCC) milk before milking. If these are not achieved, milk quality and production can be negatively affected. The ultimate objective of premilking udder preparation is to facilitate harvesting high-quality milk from cows as gently, completely, and quickly as possible (Wieland et al, 2020).

Timing plays a critical role in milking preparation and can be affected by your milking routine. One of the most recommended milking preparation routines consists of four steps: dip, strip, dry, and apply. This process should take between 60 and 120 seconds from first stimulation to unit attachment. This process occurs during the "lag time," meaning the time from the first stimulation of the udder to when the unit is placed on the cow. This lag time allows the cow to release oxytocin from the hypothalamus to stimulate milk letdown from the gland cistern. However, within this overall lag time, there are other times that need to be taken into consideration. This includes contact time of the pre-dip, timing of manual stimulation, and timing of unit attachments.

If you are using a commercial pre-dip, the contact time for the dip should be included on the label. The contact time is the recommended time the dip should remain on the teat end to kill any bacteria that may be present. In no instance should the pre-dip be wiped off immediately after applying. The other important thing to remember with any dip is to ensure adequate coverage of the teat, all the way around the teat, covering three-quarters of the way up the teat to maximize effectiveness. Most pre-dips recommend between 15 and 20 seconds of contact time. If you are not achieving the proper contact time, milking routines should be adjusted to meet those recommended times.

Manual stimulation, or forestripping, of the udder is important to begin the release of oxytocin. A vigorous 3–5 strips from each teat not only provides good stimulation, but also removes the milk located in the teat cistern. This milk contains the highest levels of SCC within the udder. This process also allows those milking to observe any abnormalities in the milk, aiding in the detection of mastitis. The forestripping process should be no less than 10 seconds per cow.

In a 2020 Cornell University study, Holsteins milking three times a day had a milk prepping routine of no forestripping but 7 seconds of wiping or forestripping for 16 seconds. Both routines met the 90-second lag time. Results of the study revealed cows that were forestripped had shorter milking unit on-time, had higher 2-minute milk yield, lower time spent in low milk flow rate, and lower odds of exhibiting changes to the teat tissue after machine milking. In addition, cows that were stripped for 16 seconds versus the 7 seconds of wiping had decreased odds of short-term changes to the teat tissue condition. It was concluded that simply wiping teats with a cloth towel for approximately 7 seconds during premilking udder preparation does not provide sufficient tactile stimulation to elicit the cows’ maximum physiological milk-ejection capacity as compared with 16 seconds of stimulation that includes forestripping (Wieland et. al, 2020).

Regardless of the order of the milking preparation, after teats are wiped dry, the milking unit should be attached immediately. This is the point in milking preparation where the teat ends will be the cleanest. As previously mentioned, the milking unit should be attached between 60–120 seconds after initial stimulation. If units are attached too soon, the vacuum pressure at the teat end will be high due to little or no milk flow, which over time can lead to teat end damage, also known as hyperkeratosis.

When the milking unit stimulates the udder instead of a person, bimodal milking can occur. Bimodal milk flow is defined as those periods when milk flow is interrupted after removal of cisternal milk but before alveolar milk reaches the gland cistern (Erskine et al, 2019). According to Wieland et al, insufficient stimulation before milking results in delayed milk ejection and bimodal milk flow, which is associated with poor milking efficiency, impaired teat health, and possibly reduced milk yield. Proper stimulation is essential for activating the milk-ejection reflex to harvest the alveolar milk, which represents approximately 80% of the udder’s milk volume (Wieland et al, 2020). To further stress the importance of timing, in a study of cows in New York, cows that received no premilking stimulation, or prestimulation and lag times of only 30 seconds, were more likely to have bimodal milking compared to cows that were prestimulated and had 90 seconds of lag time (Erskine et al, 2019).

One consequence of not achieving proper lag times is the detrimental effect on the teat ends. As mentioned above, when milk flow is low, vacuum at the teat ends is high. Due to an inverse relationship between milk flow and vacuum-induced strain, improper stimulation worsens the effect of the milking unit on teat tissue condition (Wieland et al, 2020). Changes that can occur due to increased pressure at the teat ends include increased teat canal colonization, increased risk of new intramammary infections, and increased SCC (Wieland et al, 2020). Hyperkeratosis of the teat ends is an irreversible condition, so early detection of trauma to the teat ends should warrant a change in the milking routine. A teat with hyperkeratosis is harder to clean, allows more bacteria to enter the teat cistern, and makes the quarter more susceptible to mastitis infections.

While timing of milking preparation is important, there are even more times to be aware of. After the unit has been attached, pay attention to unit on-time for your cows. This period from unit attachment to detachment should occur within 3.5 to 5 minutes. Improper milk preparation will increase unit on-time and often go hand-in-hand with overmilking. Overmilking of cows should be one minute or less. Any time over this causes teat-end damage. Overmilking can happen for several reasons. Stressed cows, especially fresh heifers that are unfamiliar with the milking routine, can hold their milk, leading to overmilking. Other causes include ​improper prepping procedures, lack of knowledge of when to remove milking unit, or inaccurate detacher settings on automatic take-off machines.

From the timing of pre-dip, unit attachment, unit on-time, and the overall milking process, it is evident that timing plays a key role in successfully harvesting good quality milk in a timely fashion while preserving the health of the teat end and mammary system. Improper udder stimulation during the milking preparation can lead to many adverse effects such as increased unit on-time, poor milk let down, decreased milk flow, overmilking, and increased risk of mastitis infections. Therefore, timing should be taken very seriously to optimize your milking routine.

References

Erskine, R. J., Norby, B., Neuder, L. M., & Thomson, R. S. (2019). Decreased milk yield is associated with delayed milk ejection. Journal of Dairy Science. 102(7), 6477-6484. 

Wieland, M., Virkler, P. D., Weld, A., Melvin, J. M., Wettstein, M. R., Oswald, M. F., Geary, C. M., Watters, R. D., Lynch, R., & Nydam, D. V. (2020). The effect of 2 different premilking stimulation regimens, with and without manual forestripping, on teat tissue condition and milking performance in Holstein dairy cows milked 3 times daily. Journal of Dairy Science. 103(10), 9548-9560.