Factors Influencing the Setting of Automatic Teat Cup Removal at the End of Machine Milking in Dairy Cows—An Overview

Simple Summary

Rising milk production per cow has extended milking times in recent decades. However, milking time is an important aspect of dairy farming, whether in conventional or automated milking systems. Therefore, automatic teat cup removal (ATCR) at the end of machine milking is of great importance for milk production, milk quality and udder health. There are several factors that influence the setting of the ATCR at the end of machine milking. From a practical point of view, an ATCR at a milk flow of 0.2–0.3 kg·min⁻¹ is a useful level to achieve various objectives on dairy farms, such as maintaining udder health, reducing residual milk, increasing milk production and improving milk quality when using a low vacuum 34–36 kPa in the milking machine. However, if the milking machine operates at a higher vacuum, it is possible to program a higher ATCR at a milk flow of up to 0.5 kg·min⁻¹ to shorten the milking time and avoid the negative effects of the high vacuum on the teat tissue.

Abstract

Overmilking occurs when the teat cups remain attached to the udder during milking, even though there is little or no milk flow. This puts pressure on the teat tissue and reduces milk production due to longer milking times, meaning fewer cows are milked per hour. Therefore, the correct removal of the teat cup at the end of mechanical milking is crucial for the milking process. The aim of this study was to describe the factors influencing automatic teat cup removal (ATCR) at the end of mechanical milking and to demonstrate its importance for udder health, milk production and milk quality. There are considerable differences between milking system suppliers and countries regarding the minimum removal of the teat cup at the end of the milking process. However, to ensure good milk quality, prevent teat damage and reduce the risk of mastitis, it is important to shorten the working time of the milking machine on the udder in both automatic and conventional milking systems. For this reason, several studies have shown that increasing the milk flow switch point effectively reduces milking time, especially in automatic milking systems where dairy cows are milked more than twice a day. However, when the ATCR setting was increased above 0.5 kg·min⁻¹, milk production decreased, and the number of somatic cells in the milk produced increased. Therefore, the use of ATCR at a milk flow rate of 0.2 kg·min⁻¹ significantly increased milk production, improved milk quality and maintained udder health when a low vacuum level (34–36 kPa) was used in milking machines such as MultiLactor and StimuLactor (Siliconform, Germany). In conclusion, ATCR at a milk flow of 0.2–0.3 kg·min⁻¹ is a useful level to achieve various goals on dairy farms when a low vacuum of 34–36 is used in the milking machine. If the milking machine uses a higher vacuum, it is possible to program a higher ATCR at a milk flow of up to 0.5 kg·min⁻¹.

1. Introduction

The first applications for the automatic removal of teat cups at the end of machine milking were introduced in the early 1970s [1,2,3]. However, automatic teat cup removal (ATCR) was implemented at the cluster level in the conventional milking system, while it was later implemented at the quarter level in the automatic milking system (AMS) [4,5]. In addition, this process is a labour-saving technology that has been used on a large scale on dairy farms in many countries since the 1990s [6]. Their aim was therefore to remove the teat cups without intervention by the milker as soon as the milk flow from the udder reached a certain level [7,8,9]. The ATCR can be used in any mechanical milking process in cow farms, even with different milk yields [10]. In fact, the right time to remove the teat cups is very important to avoid overmilking, which can lead to teat damage or teat cup problems [11,12,13]. The advantages of ATCR are not only better milk quality, but also that overmilking does not occur, teat condition is improved, labour is saved, and a more consistent milking process is possible [14]. The changeover to automatic removal of the teat cups is usually performed in kilograms or liters per minute of milk flow [7]. Nowadays, automatic milking systems (AMS) from various companies as well as semi-automatic milking systems such as MultiLactor and StimuLactor from Siliconform-Germany are designed and programmed in such a way that when the milk flow falls below a certain limit during milking, they change the pulsation rate and then automatically stop the milking duration and gently remove the teat cups from the udder [15,16]. This interrupts the vacuum supply to the milking cluster and ventilates the milking cluster. These limits have recently been discussed scientifically. Some scientists believe that these limits should be increased to reduce the time the teat cups spend on the udder and avoid overmilking [17], thus reducing the strain on the teats without affecting milk production [13]. Other researchers believe that the thresholds of automatic teat cup removal must be low to completely empty the udder [9,14,18], so that the fat content of the milk obtained can be higher and the bacteria have no chance to provide nutrients from the residual milk [18]. However, milk remaining in the udder can negatively affect subsequent milk production, and farmers strive to empty the udder as much as possible [14]. The objective of this study was therefore to describe the factors influencing ATCR at the end of mechanical milking and to demonstrate its importance for udder health, milk production and milk quality.

2. Importance of Automatic Teat Cup Removal

To achieve optimal milking performance on dairy farms with the goal of high milk yield and positive udder health with low somatic cell counts, a good milking system setting and an optimal regular milking routine are required [7,16,19,20]. Milk extraction has become increasingly important in recent years [9]. Therefore, good management is required in many dairy farms to reduce production costs, achieve high performance and improve milk quality [14,19], since in many countries, payment for milk delivered depends on the quantity and quality [21]. Therefore, dairy farm management strategies should strike a balance between increasing milk yield, reducing milking time and maintaining udder health to maximize net profit [18]. If a dairy cow falls ill with mastitis, the following costs must be expected: losses in the form of reduced milk yield, unusable milk, herd renewal, additional work, use of medication and veterinary treatment [22,23].

However, the function of automatic teat cup removal is to facilitate milking, ensure complete emptying of the udder and prevent blind milking [6,15,20,24,25,26]. This means that the correct timing of automatic teat cup removal must primarily serve udder health and at the same time ensure optimal milk quality [27]. Modern milking parlours have ATCR settings below 0.5 kg·min⁻¹ as standard, with some manufacturers using higher settings to reduce milking time [7,21,28,29]. It is noteworthy that many milking machines commonly use a milk flow cut-off point of 0.2 kg·min⁻¹ at udder level to signal the end of mechanical milking [9,15,16]. An example of ATCR at 0.2 kg·min⁻¹ milk flow was used on a Swiss farm with a MultiLactor milking system, which offered a very significant advantage. The labour required to remove the teat cup in the milking parlour was saved, the cows produced high milk yields of good quality, and the udders remained healthy. These results were achieved because the following milking parameters were used in the MultiLactor milking system: milking vacuum 34 kPa, pulse frequency 60 cycles/min, pulsation ratio 60:40, pulsation type sequential (25% offset from quarter to quarter) and air intake periodic in teat cup (Bio-Milker) (

Table 1. The average (LSM ± SE) milk parameters of a commercial dairy farm [16].

Parameters *	LSM ± SE **	Minimal Value	Maximal Value
Milk yield kg/day	35.84 ± 0.28	7.10	68.60
Fat %	4.36 ± 0.02	2.27	7.74
Protein %	3.28 ± 0.01	2.11	5.02
Lactose %	4.75 ± 0.01	3.59	5.25
Urea mg/dL	20.65 ± 0.20	5.00	35.00
SCC × 103 cells/mL	99.63 ± 6.48	6000	200,000
Lactation number	3.31 ± 0.04	1.00	8.00

* The results came from 170 Holstein-Friesian dairy cows over a period of one year. In addition, the cows were milked three times a day in a rotary milking parlour with 25 MultiLactor milking units and automatic teat cup removal at a milk flow of 0.2 kg·min⁻¹. ** LSM ± SE: Least square means ± standard error.

).

It is worth noting that the automatic removal of the teat cups is based on milk flow and not on time, so it is a necessary process to ensure that dairy cows do not suffer from overmilking, thus reducing the likelihood of mastitis and other udder health problems [11,12,30]. However, in some milking systems, the switch point settings for cluster removal are overridden if the milking time exceeds a certain duration [31]. In general, the setting for automatic teat cup removal must not be set too low or too high [32]. If too much milk remains in the udder after mechanical milking, this provides an ideal culture medium for the proliferation of udder bacteria, leads to a low-fat content of the milk obtained and has a negative effect on subsequent milk production [14]. On the other hand, if the teat cups are removed too late, the worst-case scenario is overmilking, and the condition of the teat deteriorates, as most milking systems work with a high vacuum (>42 kPa) [33]. Therefore, numerous studies have attempted to increase milk flow rate by automatically removing teat cups to shorten milking time, improve cow comfort and not compromise milk yield [9,13,31]. The results have shown that a system modification to optimize the switch settings for automatic teat cup removal can significantly increase the efficiency of a milking parlour on dairy farms [7]. Although such experiments were conducted only over a short period of time, daily milk yield was lower when the automatic teat cup removal settings were increased. For example, Magliaro and Kensinger [21] clearly showed that increasing automatic teat cup removal from 0.48 to 0.8 kg·min⁻¹ milk flow reduced milking time by 11.1% while reducing daily milk yield by 2.5% (Figure 1).

It should also be noted that by increasing the milk flow switching points, the amount of residual milk that is not collected during machine milking can be significantly increased. The average residual milk yield at quarter level increased by 1.3 kg as the switchover point for quarter milk flow was increased from 0.2 kg·min⁻¹ to 1.0 kg·min⁻¹ [29]. However, there did not always seem to be a difference in daily milk yield with different ATCR settings. When using lower ATCR settings (0.2 and 0.4 kg·min⁻¹), no difference in milk yield was observed between the two settings [34,35]. Studies by Upton et al. [9] have also shown that when using different ATCR settings (0.2, 0.4, 0.6 and 0.8 kg·min⁻¹), no significant differences in milk yield were observed, and daily milk yields were 18.3, 18.2, 18.2 and 18.1 kg/animal/day, respectively.

3. Factors Influencing Automatic Teat Cup Removal

3.1. Automatic Teat Cup Removal and Degree of Udder Emptying

A complete milking routine has been proven to produce good results as it allows complete milking of the cow’s udder and significantly reduces the risk of blind milking (blind milking is a milking in which there is no milk flow from the teat, although a vacuum is applied to the teat canal) [13,29,36]. However, the milk remaining in the gland must be distinguished from residual milk. This milk can be mechanically extracted, but the amount of milk remaining in the alveolar space at the end of milking (residual milk) can only be obtained by administering exogenous oxytocin at supraphysiological concentrations [36,37,38]. In addition, if the teat cup is automatically removed at the end of the milking process without the udder being completely emptied, there will still be a larger amount of milk in the udder after milking, especially if there was insufficient stimulation before milking [10,21,29,39]. The amount of milk remaining after mechanical milking blocks milk synthesis because it serves as a local control of the secretion of mammary epithelial cells in the gland [40,41]. It is known that the activity of mammary epithelial cells is influenced by proteins, hormones, growth factors, peptides and chemicals. Such a mechanism has been demonstrated by half-udder experiments [42]. However, the degree of filling of the glandular cistern between milking intervals is a factor that can influence milk synthesis in the udder epithelial cells [43]. A study by Penry et al. [36] found that incomplete udder emptying had a significant impact on milk production rates. The fully emptied half-udder yielded an average production rate of 0.97 kg·h⁻¹ of milk, while the incompletely emptied half-udder (removal of the teat cup before 30% of milk production) yielded 0.73 kg·h⁻¹ (Figure 2).

A high amount of residual milk in the udder after milking not only has a negative effect on milk yield [44] but also impairs udder health [36,45,46]. So that a significant decrease in the lactose content of the milk and a significant increase in the somatic cell count in the incompletely emptied half-udder were observed [37] (Figure 2).

In addition, studies have shown that increased somatic cell count (SCC) was observed in milk from quarters emptied to varying degrees [10]. Numerous studies have shown that an increase in somatic cell count leads to acute mastitis when cows leave the milking parlor with incomplete udder emptying [10,46]. It is known that the amount of milk obtained during milking is closely related to the milking duration [47]. However, this does not mean that the udder must be emptied to the last drop of milk during milking. If mechanical milking requires a long time to obtain very small amounts of milk, the harm of intensive milking outweighs the benefits due to the increased stress on the teat tissue [33]. Loose, soft udders after milking are more important than milking out the last drops of milk from the udder [32]. At this point, farmers must weigh up whether the potential milk loss per cow and the lower fat content of the milk produced due to a higher ATCR setting are less valuable to them than a reduction in the herd’s overall milking time [21]. It has been proven that different udder quarter sizes lead to incomplete milk production during machine milking. The descending phase of the milk flow curve is step-like, with each step representing the end of the milk flow of a quarter and at the same time the beginning of blind milking of that quarter [33]. Therefore, the use of automatic teat cup removal requires an adapted milking technique and comprehensive pre-stimulation of the cow to achieve optimal milk yield and reduce the amount of residual milk [48]. If the milker finds that the cluster stays on the udder for too long when there is little or no milk flow, they should increase the ATCR threshold to ensure that the cluster stays on the udder for as short a time as possible.

3.2. Automatic Teat Cup Removal and Udder Health

Automatic teat cup removal is useful in all milking parlours to avoid unnecessary and udder-damaging overmilking [20]. However, the milking duration per animal is an important factor for udder health as well as for the efficiency and cost-effectiveness of mechanical milking [21,49]. Incomplete milking can lead to a reduction in milk yield, resulting in an increase in the clinical mastitis rate [44]. In addition, there are significant differences in milk yield and milking duration between quarters of the same udder. It was observed that milk production in the hindquarters increased significantly compared to the forequarters, and the difference was about 1 kg of milk [50], while Penry et al. [51] showed that hindquarters had more milk (700 g, 25%) than forequarters. Based on that, cows with extremely congenitally stepped udders should be excluded from breeding. This leads to different blind milking times in different quarters, which impairs milk yield in the remaining quarters and endangers the health of the other severely affected quarters. Therefore, the exact removal of the teat cup is very difficult due to the different volumes of the hind- and forequarters [33].

An interesting aspect pointed out by Eicker et al. [52] is that cows’ discomfort with low or no milk flow during milking can lead them to avoid the milking parlour, resulting in longer row occupancy and longer total milking time. In addition, nervous cows tended to have reduced blood oxytocin levels, which inhibited milk letdown, led to low milk flow and increased vacuum at the teat. This could accelerate cluster loss and further disrupt the milking process [53]. In the interest of udder health, the switching threshold should be chosen between 0.2 and 0.3 g·min⁻¹ milk flow [15,35]. Today, some milking specialists and scientists recommend removing the teat cups earlier, when the milk flow reaches 0.4 kg·min⁻¹ and more [31,54]. However, reduced machine-on time may improve teat tip condition and udder health [30,55,56]. Similar results were shown by Burke and Jago [6] that milking time was 11% shorter at an ATCR of 0.4 kg·min⁻¹ than at 0.2 kg·min⁻¹ (p < 0.001) and that average fat yield and SCC did not differ between treatments (p > 0.05). Studies on automatic milking systems have shown that ATCR, at a quarter milk flow of 125 g·min⁻¹, reduces milking time in both early (<80 DIM) and late lactation (>180 DIM) without causing milk losses or negative effects on teat condition. However, this experiment was conducted on only 24 dairy cows and on 12 consecutive days [57]. One study came to different results: when the ATCR of the milk flow rate was increased from 0.2 kg·min⁻¹ to 0.4 kg·min⁻¹, a higher incidence of subclinical infections caused by coagulase-negative staphylococci was observed in the 0.4 kg·min⁻¹ group [35]. In a study by Clarke et al. [58], it was found that increasing the ATCR from 0.3 kg·min⁻¹ milk flow to 0.8 kg·min⁻¹ resulted in 0.3 kg of additional milk remaining in the udder. It is known that the cow’s teat serves as a drainage channel for milk during milking and is also the main entry point for udder pathogens. Mechanical milking places mechanical stress on the teat tissue. Farmers should therefore monitor the milking machine during milking, check the milk flow regularly and remove the teat cup as soon as possible if the milk flow falls below a certain level. To keep the udder healthy and empty it completely during mechanical milking, as well as to save time, the installation of a milking machine with automatic removal of the teat cups is the best solution [5]. This prevents blind milking and many cases of mastitis. However, long milking times and low milk flow place excessive strain on the teats and, in the long term, impair resistance to infections [32]. In addition, the International Dairy Federation has recently recommended a specific ATCR value for each farm [14]. It is noticeable that despite the threshold for automatic removal of the milking cluster being correctly set, much residual milk sometimes remains in the udder. The main causes of incomplete milking are deficiencies in milking technique and routine, such as insufficient pre-stimulation, crookedly hanging milking clusters, pulsator defects and teat cup liners of the wrong size or poor quality [21]. Many milkers have found that an increase in the cell count in the milk produced leads to acute mastitis when cows leave the milking parlour with poorly milked udders [36]. The reason for this is that the pathogens and their metabolic products can remain in the infected udder because they receive sufficient nutrients from the residual milk present in the udder [18,59]. However, milking is important both for achieving peak performance and for the cow’s udder health [18]. More and more farms are doing without post-milking, not only for economic reasons, but also because they consider post-milking unnecessary due to the habituation effect. Therefore, it is very important to maintain the correct distance between udder preparation, including pre-stimulation, and attachment of the milking cluster to completely empty the udder without subsequent milking and to avoid over milking [15]. On the other hand, blind milking can occur during subsequent milking of the cow, as the udder is stressed or damaged by the continuous pulsation at the teats after the milk flow has stopped. Technical solutions are intended to remedy this situation, for example, by means of optical signals that indicate the end of the milk flow (at an ATCR setting of 0.3 kg·min⁻¹) or by means of automatic shutdown devices that switch the pulsator to the relief cycle at the end of the milk flow. This signal indicates the end of milk flow after completion of the main mechanical milking and switches the pulsation to a lower vacuum level. This means that after the milk flow has stopped, the milking cluster is removed from the udder, even if there is still loose residual milk in the udder. However, on larger farms that invest in new milking technology, this automatic emptying system is often combined with a post-milking machine to ensure complete milking of the udders. This is the only way to ensure consistently high milk yields, good persistence and stable udder health [60]. Hyperkeratosis of the teat ends is the result of compression and stretching of the skin around the outer end of the teat canal during the massage phase of milking. Excessive hyperkeratosis leads to very rough and cracked teat ends, which are even more difficult to keep clean. Therefore, the correct timing of ATCR is very important to keep the teat healthy [14]. An interesting aspect is presented in the following table (

Table 2. The effect of automatic teat cup removal (ATCR) flow-rate thresholds on milking parameters and milk contents in dairy cows.

Parameters	ATCR Setting *		SED **	Significance
	ATCR 0.2 kg·min−1	ATCR 0.4 kg·min−1
Milking duration (min)	6.82	6.04	0.044	<0.001
Post-milking strip yield (Kg)	0.19	0.35	0.071	<0.001
Daily milk fat yield (kg)	0.78	0.77	0.007	NS
Daily milk protein yield (kg)	0.65	0.64	0.003	<0.05
SCC (log10)	1.79	1.81	0.021	NS

* Treatments were applied for three weeks from peak lactation (Group 1, n = 81, ATCR 0.2 kg·min⁻¹; Group 2, n = 80, ATCR 0.4 kg·min⁻¹), followed by a one-week transition period with ATCR set to 0.3 kg·min⁻¹, before the second, three-week treatment period (Group 1, ATCR 0.4 kg·min⁻¹; Group 2, ATCR 0.2 kg·min⁻¹). ** SED: Standard error.

): the effect of ATCR flow rate thresholds on average milking time, post-milking strip yield, daily milk fat yield, daily milk protein yield and SCC [6].

From the table (Table 2), the parameters studied provided better results in terms of milk quality and udder health at an ATCR of 0.2 kg·min⁻¹ than at an ATCR of 0.4 kg·min⁻¹, although the study was conducted only over a short period from October to the beginning of December 2009. However, the visibly better results when using ATCR at 0.2 kg·min⁻¹ than at 0.4 kg·min⁻¹ regarding somatic cell count in milk and fat content in the milk obtained could show significant differences if the trials are conducted over a longer period and more cows are used. Gasparik et al. [18] clearly showed that reducing ATCR milk flow from 0.85 to 0.65 kg·min⁻¹ had a positive effect on udder health, with a significant decrease in SCC from 389.67 ± 4.635 × 10³ to 324.89 ± 4.580 × 10³ (−64.78 × 10³/mL, p < 0.01). These results showed that small amounts of milk remaining in the udder after milking did not increase the reinfection rate or SCC [58,61].

3.3. Automatic Teat Cup Removal and Daily Milking Frequency

Practical studies have shown that increased milking frequency and incomplete milking have different effects on milk yield as well as milk synthesis and milk storage, which are important for optimizing milking performance in dairy herds [44]. However, a change in milking frequency or milking duration resulted in a rapid response to SCC in milk within a few days [62,63]. Therefore, the setting of the milk flow limits depends on the daily milking frequency. Frequent milking has been shown to increase milk yield. However, milking three times a day increased milk yield by 5–25% compared to milking twice a day [64]. Weaver and Hernandez [65] found that milking frequency affects the amount of residual milk after mechanical milking. Bruckmaier and Hilger [66] and Caja et al. [67] reported that the increase in intramammary pressure after udder stimulation and cisternal capacity can be influenced by the time between milkings. These can play a role in a cow’s response to different ATCR settings. However, with optimal ATCR setting, a smaller improvement in milking time is achieved [21]. Several studies have shown that it is difficult to compare milking times after the introduction of delayed ATCR due to differences in the milking systems used, milking frequency and milk yield. It has been found that cows milked twice a day tend to have a lower milk production rate than cows milked three times [45]. However, if 30% of the milk remains in the mammary gland after milking, this has a greater impact on milk yield, as the loss of milk yield cannot be reversed even by increasing the milking frequency [44]. Normally, at higher milking frequencies, the milk flow limits for automatic teat cup removal are set higher. Therefore, if milking is performed three times a day, intensive milking must be avoided. In this case, the time the milking machine spends on the udder should be minimized. It is recommended to limit the milk flow to a maximum of 0.7 kg·min⁻¹ [54]. When milking dairy cows twice a day, an ATCR of 0.2 to 0.25 kg·min⁻¹ is useful if the milking machine is operated at low vacuum (34–36 kPa), as is the case with the MultiLactor and StimuLactor [16]. However, for modern dairy cow breeds (European breeds), an ATCR of 0.3 kg·min⁻¹ may also be appropriate. For other breeds around the world, using the correct milking machine and effective teat cup removal is very important, as milk production, udder storage capacity and milk removal vary greatly in these breeds compared to European breeds.

3.4. Automatic Teat Cup Removal and Lactation Number

Based on the observations, it was found that parity has no effect on milk yield or milking time [21]. However, differences in milking time may be related to the individual animal rather than its age. It is also noted that 76% of the variation in milking time is due to the cow. A previous study found that increasing the ATCR from 0.8 to 1.2 kg·min⁻¹ in different dairy cow parities resulted in a significant reduction in milking time and an improvement in teat tissue condition without negatively affecting milk yield, milk component yield or udder health [27]. On the other hand, a previous study showed that milk production and milking time in early lactation (12 weeks after parturition) were higher in multiparous dairy cows than in primiparous dairy cows [35].

3.5. Automatic Teat Cup Removal and Stage of Lactation

It was discussed whether the ATCR threshold needs to be changed depending on the stage of lactation. It was found that total milk yield, milk production per hour and average milk flow were higher in early lactation cows (<80 days in milk) than in late lactation cows (>180 days in milk) [57]. However, an ATCR of 125 g·min⁻¹ per quarter in the AMS system has been shown to reduce milking time in both early and late lactation without any loss of milk production or negative effects on teat condition. Finally, by adjusting the ATCR accordingly, teat condition and throughput in the milking parlour can be significantly improved while maintaining the quality and quantity of milk obtained.

3.6. Uncontrolled Change in the Setting for Automatic Teat Cup Removal

Some farmers have switched off the automatic shut-off devices or reset the threshold values, i.e., they leave the milking machine’s teat cups hanging on the udder of many dairy cows for longer to completely empty the udder and thus extract more milk or fat from the udder. Unfortunately, under these unfavourable milking conditions, the teats are damaged and the pathogen defense no longer functions or only functions to a limited extent, as the teats are exposed to permanent mechanical stress from the teat liner [68]. This situation always occurs when a high-pressure difference quickly builds up between the inside of the teat cup liner and the pulse space during the relief phase, and the shaft of the teat cup liner presses against the teat tip at high speed. This is always the case when milking is performed blindly and only a small amount of milk remains at the end of the milking process. The results of Rasmussen [69] clearly showed that an extension of milking time can have negative effects on teat and udder health. However, overmilking occurs in both conventional and automatic milking systems. The main short-term effects of delaying teat cup removal are changes in teat colour and ring formation at the teat base, while the long-term effect of blind milking leads to hyperkeratosis [33] (Figure 3).

Based on these results, farmers were advised to leave the teat cup on the udder only for short periods of time to ensure that the teat remains healthy, soft and well supplied with blood. In addition, an undamaged teat sphincter can close properly again within a short time after milking. But invisible damage is also important for udder health: the permanent compression of the teat and the associated high negative pressure during milking damages the inner lining of the teat canal and sometimes also the teat cistern.

4. Conclusions

Correct removal of the teat cups is important to avoid overmilking, which can lead to teat damage or problems with the teat liner.

To maintain a healthy udder over a longer period, a low setting of 0.2 kg·min⁻¹ milk flow rate (automatic teat cup removal) is recommended when using a milking machine with low vacuum (34 kPa), a pulsation rate of 60 cycle/min, sufficient stimulation before milking and twice-daily milking, such as the MultiLactor and StimuLactor milking systems.