Patent Publication Number: US-2023142734-A1

Title: Milking control arrangement and milk extracting system

Description:
TECHNICAL FIELD 
     This document discloses a milking control arrangement and a milk extracting system. More particularly, a milking control arrangement and a milk extracting system are described, for adjusting a milking parameter of a milk extraction unit, thereby improving milk extraction from a teat having a size or shape deviating from an average size/shape of teats of the herd. 
     BACKGROUND 
     On a dairy farm, milk is typically extracted from the animals by putting a teat cup with a liner on a teat of the animal and apply milking vacuum under the tip of the teat, and a pulsation vacuum. Hereby, the rhythmical suckling of a calf is imitated so that sucking by the milking vacuum is interrupted by rhythmical motions, opening and closing of the liner caused by the pulsation vacuum. Consequently, the teats are exposed to massage which stimulates oxytocin release of the animal, which in turn activates the milk ejection reflex. Also, congestion in the teat end is prevented by the applied massage. 
     However, teats are often different both in size and in shape within the herd, for example depending on race, age of the animal, number of births, situation in the lactation cycle, genetic variations, hormone variations, accidents, provided fodder quality/quantity, temperature, etc. The teat size/shape may be different not only between different animals, but also the teats of a single animal may have different sizes/shapes. The teat size/shape of one specific animal may also vary over time due to for example hormone variations. The teats may even change size and/or shape during the milking process itself, as blood and lymph is accumulated in the teat during the milking. 
     It is desired to evacuate the milk from the animal fast and as complete as possible while reducing teat congestion and avoid injury on the teats. For achieving these goals, an airtight fitting between the teat and the liner is required in order to avoid or at least minimise liner slip and/or the risk of the teat cup/liner to slide off the teat during pulsation. 
     A conventional approach is to estimate an average size/shape of the teats of the herd at the farm and apply the same liner to all animals/teats, disregarding the differences in teat size/shape. The result is however a milking process which is suboptimal for the teats that deviate from the average teat configuration. 
     On the market there are an enormous number and range of liner designs, which all try to achieve the above-mentioned goals. As an example, the diameter of a mouthpiece lip of the liner ranges from 18-27 mm and the bore diameter from 20-28 mm. The reason is mainly due to the variation in teat size and teat configuration among breeds. 
     In case the liner is too short, the barrel will not have enough space to collapse under the teat leading to inefficient milking, while a too large liner might cause frequent slipping. In case the liner is applied onto a teat having a smaller diameter than the average teat of the herd, that the liner is selected for in order to optimise the milking, severe air slip may result when the milking vacuum is applied, due to insufficient fit between the liner and the teat. The air slip results in reducing the milking vacuum (i.e. increasing the applied under-pressure in comparison with the desired under-pressure/vacuum), leading to inefficient milking of the teat, and possibly even cause the teat cup/liner to slip of the nipple. 
     A recently developed milking method is called boost. Boost means that the milk extraction starts with applying milking vacuum at a first level and when the milk flow of the teat has increased over a threshold limit, and thereafter increasing the milking vacuum (i.e. lowering the under pressure). In case the liner/teat fit is good, this works fine, but in case of bad fit, the air slip instead precludes increase of the milking vacuum. Thus, the problems of bad fit between the teat and the liner increase when boost is applied. 
     A potential solution to at least some of the above-mentioned problems is presented in the document WO 00/04768. The solution comprises providing a plurality of sets of teat cups with liners of different sizes at a milking apparatus/robot. The size/shape of a teat of an animal to be milked is analysed and a matching teat cup/liner is applied to it during milk extraction. 
     The disclosed solution may to some extent solve the above-described problem at least partly, however, the solution will require a large amount of additional teat cups/liners, which adds costs to the milking apparatus, both in additional hardware and in terms of added maintenance costs, in comparison with the conventional one-size-fits-all teat cup/liner concept. The rubber of the liners will age over time when in contact with the milk and the liners have to be replaced at regular time intervals, which will generate both additional costs and more work for the farmer. A more severe disadvantage is that the constant swapping between different liners is time consuming and will extend the required time each animal has to spend in the milking robot/arrangement, thereby reducing the number of animals that can be served by the milking robot/arrangement, compared with the conventional concept. 
     It appears that further investigations and development is required for improving milk evacuation of animals having deviating teat configurations. 
     SUMMARY 
     It is therefore an object of this invention to solve at least some of the above problems and improve milking of an animal. 
     According to a first aspect of the invention, this objective is achieved by a milking control arrangement configured to obtain teat size data of at least one teat of an animal to be milked. 
     Also, the milking control arrangement is configured to adjust a milking parameter of a milk extraction unit when milk is extracted from the teat, based on the obtained teat size data of the teat. 
     Thereby, by adapting the milking process to the configuration of the individual teat, the milking could be optimised for the teat instead of an average teat. Thanks to the provided solution, compensation for the differences in teat size, and thereby differences in fit against the liner, could be made mainly by control of adjusted milking parameters which makes the disclosed solution easily implemented. Hereby, the milk extraction is improved. 
     In an implementation of the milking control arrangement according to the first aspect, the milking control arrangement may also be configured to obtain a milk flow value of the teat when milk is extracted from the teat. Furthermore, the milking control arrangement may be configured to adjust the milking parameter of the milk extraction unit when milk is extracted from the teat, based on the obtained milk flow value of the teat. 
     By measuring the milk flow value of the teat and adapting one or several milking parameters of the milk extraction unit to the measured milk flow, an adaptation of the milk extraction is made to the constraints of the individual teat, leading to improved milking. 
     In yet an implementation of the milking control arrangement according to the first aspect, the milking control arrangement may be additionally configured to obtain liner data of a liner of the milk extraction unit, applied to the teat. Also, the milking control arrangement may be configured to adjust the milking parameter of the milk extraction unit when milk is extracted from the teat, based on the obtained liner data of the liner applied to the teat. A liner comprises a barrel that is the part of the liner that is in contact with a teat of an animal during milking. The liner data is associated with the dimensions of the barrel, preferably the diameter of the barrel at one or several cross-sections along a longitudinal axis of the barrel and/or the wall thickness of the barrel at one or several cross-sections along a longitudinal axis of the barrel. 
     Hereby, differences in teat configuration may be compensated by application of differently shaped respective liners, leading to better fit between liner and teat and reduced slip which makes the milking process more efficient. 
     In another implementation of the milking control arrangement according to the first aspect, the adjusted milking parameter comprises anyone, or a combination of: a milking vacuum applied to the teat, a pulsation ratio of the applied pulsation pressure, pulsating pressure levels, fixed D-phase/adjustable B-phase. 
     In another implementation of the milking control arrangement according to the first aspect, the milking control arrangement may also be configured to obtain teat size data of a plurality of teats of the animal and adjust the milking parameter of the milk extraction unit individually for each respective teat from which milk is extracted. 
     In yet another implementation of the milking control arrangement according to the first aspect, the milking control arrangement may be configured to determine, based on the obtained teat size data, a difference in size between two teats. Also, the milking control arrangement may be configured to adjust the milking parameter of the milk extraction unit by applying different milk flow switch points for adjusting the milking vacuum applied to the respective teat based on the determined difference in size between the two teats. 
     It thus become possible to have milk flow switch points that are individually adapted to the conditions and ability of each teat, making the milking process more efficient. 
     In another implementation of the milking control arrangement according to the first aspect, the milking control arrangement may be configured to determine, based on the obtained teat size data, a difference in size between two teats. The milking control arrangement may also be configured to adjust the milking parameter of the milk extraction unit by applying different pulsation ratio of the applied pulsating pressure, or pulsating pressure levels, or B-phase lengths, or milking vacuum applied to the teats based on the determined difference in size between the two teats. 
     According to a second aspect of the invention, this objective is achieved by a milk extracting system. The milk extracting system comprises a milk extraction unit, configured to extract milk of an animal. The milk extracting system also comprises a milking control arrangement according to the first aspect, or any implementation thereof. 
     Thereby, by adapting the milking process to the configuration of the individual teat, the milking could be optimised for the teat instead of an average teat. Thanks to the provided solution, compensation for the differences in teat size, and thereby differences in fit against the liner, could be made mainly by control of adjusted milking parameters which makes the disclosed solution easily implemented. Hereby, the milk extraction is improved. 
     In an implementation of the milk extracting system according to the second aspect, the milk extracting system may also comprise a sensor configured to determine teat size of at least one teat of the animal to be milked. 
     In another implementation of the milk extracting system according to the second aspect, the milk extracting system may comprise an animal identifying device, configured to identify the animal. The milk extracting system may also comprise a memory device configured to store, associated with an identity reference of the animal, teat size data of teats of the animal, and/or at least one milking parameter to be applied when milk is extracted from a teat of the animal. 
     In yet another implementation of the milk extracting system according to the second aspect, the milk extracting system may comprise a set of teat cups, comprising at least one first teat cup and at least one second teat cup, wherein the first teat cup comprises a liner that has a different dimension than a liner of the second teat cup. 
     Other advantages and additional novel features will become apparent from the subsequent detailed description. 
    
    
     
       FIGURES 
       Embodiments of the invention will now be described in further detail with reference to the accompanying figures, in which: 
         FIG.  1 A  illustrates a milk extracting system according to an embodiment, in a scenario wherein milk is extracted from the animal. 
         FIG.  1 B  illustrates a milk extracting system according to another embodiment, in a scenario wherein milk is extracted from the animal. 
         FIG.  2 A  illustrates an identification means of an animal and an udder with one teat deviating from the other teats in size and shape. 
         FIG.  2 B  illustrates a device for determining teat size data and thereby detecting a teat deviating from the other teats in size and shape. 
         FIG.  3    illustrates an arbitrary example of a detected difference in size and shape of a certain teat and a herd average teat, used as reference teat. 
         FIG.  4    schematically illustrates a teat cup cluster and therein comprised components. 
         FIG.  5    is a diagram that illustrates examples of milk flow per time unit during milk extraction according to some examples. 
         FIG.  6    is a diagram that illustrates an example of a pulsation cycle divided into four different phases A, B, C and D. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the invention described herein are defined as a milking control arrangement and a milk extracting system, which may be put into practice in the embodiments described below. These embodiments may, however, be exemplified and realised in many different forms and are not to be limited to the examples set forth herein; rather, these illustrative examples of embodiments are provided so that this disclosure will be thorough and complete. 
     Still other objects and features may become apparent from the following detailed description, considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the herein disclosed embodiments, for which reference is to be made to the appended claims. Further, the drawings are not necessarily drawn to scale and, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein. 
       FIG.  1 A  illustrates a milk extracting system  100  in a scenario wherein milk is extracted from an animal  110 . The animal  110  is comprised in a herd of animals for dairy farming at a farm  105 . 
     “Animal” may be any arbitrary type of domesticated female mammal such as e.g. cow, goat, sheep, camel, horse, dairy buffalo, donkey, yak, etc. 
     The milk of the animal  110  may be extracted by a milk extraction unit  120  comprised in a rotary milking parlour, in an automated robotic milking system, bucket milking arrangement, a pipeline milking plant or similar, just to mention some few arbitrary examples. 
     In the illustrated example of the milk extracting system  100 , the milk extraction unit  120 , and various milking parameters of the milk extraction unit  120  is controlled by a milking control arrangement  130 , in this case via a wireless communication interface via a respective transceiver  125 ,  135 . 
     The milk extracting system  100  may also comprise a sensor  140  which may capture an image, or several images of the teats of the animal  110  to be milked. These images may be provided to the milking control arrangement  130 , which may utilise the images for estimating teat size/shape of the teats of the animal  110 , and also estimate a deviation size between the determined teat size and a reference teat size/shape of an average teat of an average animal of the herd at the farm. 
     Based on the obtained teat size data of the teats of the animal  110  to be milked, the milking control arrangement  130  may determine an appropriate milking parameter for the milk extraction unit  120  to apply when milk is extracted from the respective teats. 
     The adjusted milking parameter may for example comprise anyone, or a combination of: a milking vacuum applied to the teat, a pulsation ratio of the applied pulsation pressure, pulsating pressure levels, and/or fixed D-phase/adjustable B-phase. 
     “Milking vacuum” in the current context refers to the vacuum, or under-pressure, used to extract milk from the teats. 
     In some embodiments, the milk extracting system  100  may comprise a database  150 , in turn comprised in or attached to the milking control arrangement  130 . Various data such as appropriate milking parameters to apply by the milk extraction unit  120  for different teats may be stored, associated with teat data, i.e. teat size such as teat diameter, teat length and/or teat shape. The milking control arrangement  130  may, when having determined teat configuration, use the teat data as input value in the database  150  and achieve the appropriate milking parameter in return, which then may be sent to the milk extraction unit  120  via the wireless transceivers  125 ,  135 . 
     In other embodiments, the database  150  may comprise appropriate milking parameters, associated with an identity reference of an animal  110 , and/or a specific teat of the animal  110 . By determining the identity of the animal  110  to be milked, by the sensor  140  or by some other animal identifying device, the milking control arrangement  130  may use the identity reference of the animal  110  as an input value for achieving the appropriate milking parameters to apply, which then may be provided to the milk extraction unit  120 . 
     A general inventive concept is to obtain teat size data of at least one teat of the animal  110  to be milked, for example based on sensor detection by the sensor  140 , by determining an identity of the animal  110  and obtainment of teat size data stored associated with an animal identity reference of the database  150 , by obtaining an estimation of teat size made by an agricultural manager, etc. 
     Based on the obtained teat size data of the teat/-s, a milking parameter of the milk extraction unit  120  is adjusted when milk is extracted from the teat. 
     The milking parameter to be adjusted may comprise one or more of a milking vacuum level applied to the teat, a pulsation ratio of the applied pulsation pressure, pulsating pressure levels, fixed D-phase/adjustable B-phase. 
     By adjusting the milking parameter during milk extraction depending on the size and shape of the teat, previously discussed disadvantages enumerated in the background section could be eliminated, or at least reduced. For example, lowering the applied milking vacuum (in comparison with milking of an average teat) leads to avoidance of air slip, and/or avoidance of that the teat cup slips of the teat, thereby making the milking process more efficient. 
     The concept of average teat may be regarded as an estimated average size/shape of the teats of the herd at the farm. 
     In some embodiments, the pulsation pressure levels may be adjusted based on size and shape of the teat, and milk flow value of the teat when milk is extracted from the teat. 
     Thanks to the provided solution, it is possible to dynamically adjust the milking vacuum of each teat depending on the teat size data, so that an increased milking vacuum may be applied when the fit between the liner and teat is good and vice versa. Thereby the milking efficiency is improved, by reducing the milking time per animal  110  and also by reducing the risk of air slip between the liner and the teat. It is also estimated that teat condition of the animal  110  is increased. 
       FIG.  1 B  also illustrates a milk extracting system  100  in a scenario wherein milk is extracted from an animal  110 . The animal  110  is comprised in a herd of animals for dairy farming at a farm  105 . 
     The animal  110  typically has an udder  210 , comprising a set of teats. The number of teats on the udder  210  is different for different species of animals  110 ; for example, a sow has normally  16  teats, a cow has 4 while a sheep or a goat have 2, etc. 
     In the illustrated embodiment, the milk extraction unit  120  is embodied as a milking robot, which may be part of an Automatic Milking System (AMS), sometimes also referred to as a Voluntary Milking System (VMS). The milk extraction unit  120  may comprise a cluster of teat cups  160 , which in turn comprises a plurality of teat cups  161 ,  162 ,  163 ,  164 , which each one is configured for holding a liner  161   a ,  162   a ,  163   a ,  164   a.    
     The liner  161   a ,  162   a ,  163   a ,  164   a  is the only part of the milk extraction unit  120  which is in direct contact with the teat. Design/selection of the liner  161   a ,  162   a ,  163   a ,  164   a  therefore is important for optimal milking and teat treatment. The liner selection may be made by estimating an average teat size/shape of the herd. All the selected liners  161   a ,  162   a ,  163   a ,  164   a  may be of the same size, or of different sizes in different embodiments. 
     When the animals  110  are cows of Holstein Friesian race, it has been observed that the two frontal teats often are longer and thicker than the two rear teats (in about 70% of the observations). Thus, the two liners  161   a ,  162   a  applied on the two frontal teat cups  161 ,  162  may have a larger dimension than the two liners  163   a ,  164   a  applied on the two rear teat cups  163 ,  164 , to be better adapted to the actual teats of the Holstein Friesian cow. 
     Thus, the liners  161   a ,  162   a ,  163   a ,  164   a  may be selected to fit an average teat of the herd at the farm  105 . 
     In some embodiments, the farm  105  may have several milk extraction units  120  (milking robots), which may have different liner sizes. The different milk extraction units  120  may thus be dedicated to animals  110  having teats of different sizes, i.e. small teats animals may only be welcome at a first milk extraction unit  120  while big teats animals are directed towards a second milk extraction unit  120 . Hereby, an improved fit between liner  161   a ,  162   a ,  163   a ,  164   a  and teat is achieved, reducing the problems of bad fit during milk extraction, i.e. strip yield, liner slip, milking time, teat treatment and udder health. 
     The milk flow during extraction of milk may be measured for example by a milk flow meter  180   a ,  180   b ,  180   c ,  180   d  measuring the milk flow from each individual teat; or alternatively one common milk flow meter for the cluster unit, measuring the milk flow of all the teats of the udder  210 . 
     The animal  110  may be identified by an animal identifying device  170  which may be attached to the animal  110  in some embodiments, e.g. in a necklace around the neck of the animal  110 , under the hide of the animal  110 , as ear tag/-s, around the tail of the animal  110  and/or around any, some or all of the legs of the animal  110 , etc. 
     The animal identifying device  170  may comprise a transponder, such as a Radio-Frequency Identification (RFID) device in some embodiments. The transponder comprises electronically stored information for uniquely identifying the animal  110 . Such transponder may be active or passive. An active transponder comprises, or is attached to, a local power source such as a battery and may operate at hundreds of meters from a reader  135 . A passive transponder collect energy from a nearby reader&#39;s  135  interrogating radio waves. Thereby, no local power source is required in a passive transponder. 
     The reader  135  may then provide the identity of the animal  110 , as obtained from the identification device  170 , to the milking control arrangement  130 , over a wired or wireless communication interface. 
     In some alternative embodiments, the animal identifying device  170  may comprise an identification number, which may be recognised by the sensor  140 , or possibly a separate camera or scanner, in cooperation with an image recognition program of the milking control arrangement  130 , as illustrated in  FIG.  2 A . In some further embodiments, the animal identifying device  170  may comprise the identification number encoded in a graphic encoding such as e.g. barcode, European Article Number (EAN) code, data matrix, Quick Response (QR) code. Any other convenient method for identification may be utilised in some embodiments. 
     In yet some embodiments, the animal  110  may be identified based on the pattern of markings or tattoos in the animal skin, as determined by the sensor/camera  140  (or another sensor) of the farm  105  and a comparison may be made with a register over pre-stored patterns of animals in the herd. The animal  110  may alternatively be identified by the colour markings of the hide, analysed by an image recognition program of the milking control arrangement  130 . 
       FIG.  2 B  schematically illustrates an embodiment wherein the sensor  140  is embodied as a mobile phone. The farmer may download an app to his/her mobile phone and direct the mobile phone/sensor  140  towards the udder  210  of the animal  110 . An image recognition program of the app may estimate teat size data such as size (length and diameter) and shape of the teats  220   a ,  220   b ,  220   c ,  220   d . This data may be provided to the milking control arrangement  130  associated with an identity reference of the animal  110 , for storage in the database  150 . 
     Alternatively, the image recognition program of the app may provide information concerning the animal teats only for a teat  220   a  deviating from an average teat size  220   b ,  220   c ,  220   d . It may then be assumed that non commented teats are classified as being of average size/shape, in some embodiments, thereby saving information transmission and data storage requirements. 
       FIG.  3    illustrates a detected teat  220   a  having a deviating dimension than a reference teat size  220   ref , representing an average teat size of the herd. 
     The liner  161   a ,  162   a ,  163   a ,  164   a  may be selected to fit the average teat, of the reference teat size  220   ref . Thereby air slip is avoided for the majority of teats  220   a ,  220   b ,  220   c ,  220   d  of the animals  110  at the farm. The target of the disclosed solution is to avoid or at least minimise air slip of a teat deviating in configuration, i.e. size and/or shape of the teat  220   a ,  220   b ,  220   c ,  220   d.    
       FIG.  4    illustrates a cutaway view of a teat cup cluster  160  comprising teat cups  161 ,  162 ,  163 ,  164  and some components comprised therein. The teat cup cluster  160  forms a part of a milk extraction unit  120 . The teat cup cluster  160  comprises a mouthpiece  410  with an enclosed mouthpiece chamber. It is desired to select liner  161   a ,  162   a ,  163   a ,  164   a  ascertaining a substantially airtight seal of the respective teat  220   a ,  220   c . The left part of  FIG.  4    schematically illustrates the shape of the liner  161   a ,  162   a ,  163   a ,  164   a  during milk extraction, B phase of the animal  110  and the right part of  FIG.  4    schematically illustrates the shape of the liner  161   a ,  162   a ,  163   a ,  164   a  when it is collapsing during the rest phase D. 
     A consequence may otherwise be that air enters the liner  161   a ,  162   a ,  163   a ,  164   a  during the milk extraction (i.e. air slip  415 ), when milking vacuum is applied under the teat  220   a ,  220   c . Air may enter the liner  161   a ,  162   a ,  163   a ,  164   a  via the mouthpiece  410 , thereby reducing the under-pressure (milking vacuum) under the teats  220   a ,  220   c . The teat cup  161 ,  162 ,  163 ,  164  comprises a respective shell  420   a ,  420   c  forming the outer structure of the teat cup  161 ,  162 ,  163 ,  164 , configured to hold the liner  161   a ,  162   a ,  163   a ,  164   a.    
     The milking vacuum is applied to the teat  220   a ,  220   c  via a short milk tube  450  of each respective teat cup  161 ,  162 ,  163 ,  164 , which propagate the milk further to the long milk tube  460 , which in turn forward the milk to a milk tank. The milk flow may be measured via the milk flow meter  180 , here applied on the long milk tube  460 , measuring the milk flow from all the teats  220   a ,  220   b ,  220   c ,  220   d  of the animal  110 . 
     The teat cup cluster  160  may comprise a manner of controlled air intake, e.g. an air vent, which may be applied on the claw, on the short pulse tube  440  or on some other convenient location. 
     Pulsating pressure levels are applied to the pulsation chamber  430  via a short pulse tube  440 , thereby rhythmically alternating between milk extraction/B phase and rest phase D, as illustrated in the left/right respective parts of  FIG.  4   . Hereby the liner  161   a ,  162   a ,  163   a ,  164   a  will periodically open (at least to some extent) and collapse. The pulsating pressure levels applied to the pulsation chamber  430  via the short pulse tube  440  may in some embodiments vary between a pressure higher than the milking vacuum, such as e.g. atmospheric pressure, during the rest phase D while the pressure level during the milking phase B may be equal to, or higher (i.e. less under-pressure) than the milking vacuum in different embodiments. 
     An advantage by selecting a pulsating pressure level during the milking phase B that is higher than the milking vacuum is that the liner  161   a  then is exercising a radial pressure on the teat  220  also during the milking phase B, however not as large as during the rest phase D when the liner  161   a  is allowed to collapse under the teat  220 . The radial pressure on the teat  220  serves as a seal, eliminating or at least reducing air slip  415 , also for a deviating teat  220   a  for which the selected liner  161   a  is not optimal. 
     In some embodiments, one of the pulsating pressure levels in the pulsation chamber  430  may be e.g. 60-80% of the milking vacuum for teats of deviating teat size/shape. In case the milking vacuum is 45 kPa, the pulsating pressure level may be 35 kPa respective atmospheric pressure. 
     Thus, sucking is interrupted by rhythmical motions, opening and closing, of the liner  161   a ,  162   a ,  163   a ,  164   a . The force exerted by the collapsed liner  161   a ,  162   a ,  163   a ,  164   a  causes a massage to the teat. Consequently, the teats  220   a ,  220   b ,  220   c ,  220   d  are exposed to massage and congestion (e.g. of blood) in the teat end is prevented while oxytocin release and milk ejection is stimulated by the tactical movements of the collapsing and opening liner in combination with the applied milking vacuum, mimicking calf suckling. 
     The liners  161   a ,  162   a ,  163   a ,  164   a  may be made of different elastic materials, such as natural or synthetic rubber or silicone, or TPE (Thermo Plastic Elastomere), having different properties. The material used in the liner  161   a ,  162   a ,  163   a ,  164   a  may be selected based on the applied milking vacuum, which in turn may be dependent on the teat size data. 
     Principally, when the teat  220   a ,  220   b ,  220   c ,  220   d  has entered the liner  161   a ,  162   a ,  163   a ,  164   a  it stretches out vertically to about 100-200% of its premilking length under the influence of the milking vacuum. 
       FIG.  5    illustrates some examples of flow-controlled milking. It is desired to empty the udder  210  of the animal  110  as efficiently and sometimes as completely as possible, during as short time as possible (to allow for more animals per time unit to be served by the milk extraction unit  120 ) while stimulating the teats  220   a ,  220   b ,  220   c ,  220   d  properly, without harming or hurting the teats  220   a ,  220   b ,  220   c ,  220   d . A methodology that has been developed to satisfy these demands is referred to as “boost”, a kind of milk-flow controlled milking. 
     The graph in  FIG.  5    illustrates three examples of milk extraction flow; milk extraction without boost, milk extraction with boost and milk extraction with boost starting at increased milk flow level. Also, a switch point level  510  for triggering boost and an increased switch point level  520  for triggering boost are illustrated in the graph. In udder milking, the switch point level  510  may be set to about 2 kg milk per minute while the increased switch point level  520  may be set to about 3 kg milk per minute. 
     Udder milking concerns the sum of milk extraction from all the teats  220   a ,  220   b ,  220   c ,  220   d  of the udder  210 , which may be measured by a flow metre in/on the long milk tube  460 , leading the extracted milk from the teat cup cluster  160  to the milk cistern of the farm. 
     In contrast, quarter milking, which also may be exercised in some embodiments, concerns milk flow from each individual teat  220   a ,  220   b ,  220   c ,  220   d  of the animal  110 . The milk flow in quarter milking is measured by a flow metre in/on each short milk tube  450  of each respective teat cup  161 ,  162 ,  163 ,  164 . 
     During the first seconds of milking, the milk flow may be low, reaching e.g. a value of a few hundred grams of milk per minute. This may be due to insufficient stimulation (sometimes referred to as pre stimulation) of the milk ejection reflex of the animal  110 , and/or due to too short time period having passed from beginning of the teat stimulation, i.e. alveoli milk has not started to flow. 
     Nerve receptors in the skin of the teat are sensitive to pressure. Mechanical stimulation of the teat causes impulse transmission to the pituitary gland in the brain of the animal  110  whereby the hormone oxytocin is released. The hormone is transported to the udder via the blood. The time it takes between the first stimulation of the teat and milk letdown may be about 30-60 seconds but may vary between animals. 
     The milk ejection reflex, including oxytocin secretion, may also/additionally be stimulated by psychological factors such as by the presence, sight, smell and/or hearing of calves and/or by associating the milking equipment and/or procedures of milking (e.g. feeding concentrate), with milk ejection due to conditioning, or “Pavlov&#39;s dog effect”. 
     During a high flow phase, i.e. the peak in the middle of the graphs, the milk flow reaches much higher values, such as for example 3-6 kg milk per minute during udder milking. 
     At the end of the milking, the milk flow is decreased as the alveoli milk of the udder  210  is decreased due to the extraction. 
     During milk extraction without boost, the milking vacuum level is kept, either at a constant level throughout milking independently of the milk flow per time unit of the milked animal  110 , or by applying an entry vacuum, which is lower than the milking vacuum, until the alveoli milk is released. An advantage with the latter vacuum level adjustment is that the entry vacuum prevents the teat cups  161 ,  162 ,  163 ,  164  to slip off, and that the teats  220   a ,  220   b ,  220   c ,  220   d  are additionally stimulated (triggering oxytocin release). The milking vacuum level may for example be about 45 kPa while the entry vacuum may be about 35 kPa (non-limiting examples). The milking vacuum level is kept constant during the main milking phase, i.e. when alveoli milk is flowing. 
     When milking is made with boost, an adaptation of a milking parameter such as the milking vacuum level is made during the main milking phase when alveoli milk is flowing. The adaptation is made to the variation in milk flow during the complete milking and possibly also to the different udder quarters, i.e. teats  220   a ,  220   b ,  220   c ,  220   d . A lower vacuum, for example about 40-44 kPa may then be applied in the beginning of the milking, when the milk flow is below the switch point level  510 . 
     When the milk flow of the animal  110  has increased and is reaching the switch point level  510 , the milking vacuum may be increased with for example 10% up to 46-50 kPa (i.e. larger under-pressure). Hereby, milk may be extracted more rationally, at a shorter time than when extracted without boost. The switch point level  510  may be set to e.g. 2 kg milk per minute in udder milking. This may correspond to about 0.8 kg milk per minute, per teat in quarter milking. 
     The high milk flow of the teat is the reason why the milking vacuum could be increased without causing harm to the teat. 
     The boost may be applied based on the milk flow on udder level in udder milking in some embodiments. An advantage therewith is that only one flow sensor and one sensor reading is required. 
     In other embodiments, the boost may be applied based on the milk flow on quarter milking level. The switch point level  510  may then be set to e.g. 0.5 kg milk per minute, per teat, and the increased switch point level  520  may be set to about 0.8 kg milk per minute, per teat. 
     An advantage therewith is that the increased milking vacuum of the boost is applied at a moment when the milk flow of the particular teat  220   a ,  220   b ,  220   c ,  220   d  is at an appropriate level for that teat  220   a ,  220   b ,  220   c ,  220   d  for enabling an increased milking vacuum to extract the milk. 
     When a teat  220   a ,  220   b ,  220   c ,  220   d  with a configuration (size and/or shape) deviating from the average/reference teat  220   ref , it may not be feasible to apply the increased milking vacuum at the switch point level  510 , as this may lead to the previously mentioned inconveniences such as air slip  415  etc. The boost may then instead be applied at an increased switch point level  520 ; and/or not be applied at all, according to different embodiments. The increased switch point level  520  may be set to e.g. 3 kg milk per minute in udder milking, approximately corresponding to about 1.2 kg milk per minute, per teat in quarter milking. Thereby the boost application may be applied selectively, depending on the nature and the extent of the teat deviation of the individual teat, leading to efficient, yet teat friendly milk extraction. 
     In some embodiments, the increased switch point level  520  may change a pulsation ratio of the applied pulsation pressure. The four different phases A, B, C, and D of the pulsation cycle are illustrated in  FIG.  6   . 
     During phase A, the opening phase, the liner  161   a ,  162   a ,  163   a ,  164   a  starts to open resulting in milk flowing from the teat  220   a ,  220   b ,  220   c ,  220   d . During phase B, the milking phase, the milk continues to flow. The following phase C, the teat cup liner starts to collapse, and milk is prevented from flowing from the teat  220   a ,  220   b ,  220   c ,  220   d . The last phase, D, the massage phase or resting phase, the liner  161   a ,  162   a ,  163   a ,  164   a  is collapsed. The liner movement during a pulsation cycle results in milk extraction and udder massage, stimulating flow of alveoli milk. 
     The ratio of the respective phases A-D may be different in different implementations; and may also be different depending on teat size/shape of the teat  220   a ,  220   b ,  220   c ,  220   d  to be milked in some embodiments. 
     The proportions of the phases A-D, in particular between the resting phase D and the milk extraction phase B may be adapted to the obtained teat size data and the milk flow per time unit of the teat  220   a ,  220   b ,  220   c ,  220   d . Thus, the ratio may comprise an extended phase D, rest phase, when the milk flow of the teat is lower than the increased switch point level  520 . When the milk flow of the teat exceeds the increased switch point level  520 , the milk extraction phase B may be proportionally extended. 
     In some embodiments, the rest phase, phase D may be kept fixed while the milk extraction phase B may be adjusted, based on the milk flow of the teat  220   a.    
     In yet some embodiments, the pulsating pressure levels may be adjusted for the teat  220   a , based on the obtained teat size data of the teat  220   a.    
     When the teat  220   a  is deviating in configuration, i.e. size and/or shape from the average/reference teat  220   ref  more than a threshold limit, the pulsating pressure levels may be adjusted, as already briefly discussed in conjunction with the description of  FIG.  4   . 
     For example, when the teat  220   a  has a diameter approximately corresponding with the diameter of the average/reference teat  220   ref , i.e. not having a deviating configuration, the pulsating pressure level may be set to the milking vacuum during the B phase and to atmospheric pressure during the D phase. 
     However, when the teat  220   a  has a diameter which is more than e.g. 6 mm (or some other predetermined or configurable threshold limit) smaller than the diameter of the average/reference teat  220   ref , the pulsating pressure level may be set to about 60-80% of milking vacuum during the B phase and to atmospheric pressure during the D phase, depending among other things on the flexibility/stiffness and other properties of the liner  161   a . The liner  161   a  is thereby continuously exercising a certain radial pressure on the teat  220   a  over the pulsation cycle, also during the milking phase B leading to avoided air slip  415 . It is also avoided that the teat cup  161 ,  162 ,  163 ,  164  slips of the teat  220   a . The milking vacuum may be set to about 40-45 kPa. 
     The pulsating pressure levels applied to the teat  220   a  may according to these embodiments be adjusted between two distinct pressure levels during a pulsation cycle, which both are higher than the milking vacuum, such as for example variating between about 60-80% of the milking vacuum during the B phase and atmospheric pressure during the D phase. 
     In some embodiments, the pulsating pressure levels may be adjusted for the teat  220   a , based on both the obtained teat size data of the teat  220   a  and the milk flow per time unit of the teat  220   a.    
     When the teat  220   a  is determined to have a deviating configuration, i.e. size and/or shape, the pulsating pressure level may be set to about 60-80% of milking vacuum during the B phase and to atmospheric pressure during the D phase. When the milk flow of the teat  220   a  is reaching the increased switch point level  520 , the boost is triggered, and the milking vacuum is increased by about 5-20%, up to for example about 48-55 kPa. The pulsating pressure level may then also be increased correspondingly during the B phase, with about 5-20%, so that the pulsating pressure level still is about 60-80% of the milking vacuum during the B phase. The pulsating pressure level during the D phase may be set to atmospheric pressure. 
     The terminology used in the description of the embodiments as illustrated in the accompanying drawings is not intended to be limiting of the described milking control arrangement  130 , milk extracting system  100 , and/or milking method. Various changes, substitutions and/or alterations may be made, without departing from invention embodiments as defined by the appended claims. The various illustrated embodiments depicted in  FIGS.  1 - 6   , discussed in the corresponding respective section of the description may with advantage be combined with each other, for example by mixing and compiling features of some or all of the described embodiments, thereby achieving additional advantages. 
     As used herein, the term “and/or” comprises any and all combinations of one or more of the associated listed items. The term “or” as used herein, is to be interpreted as a mathematical OR, i.e., as an inclusive disjunction; not as a mathematical exclusive OR (XOR), unless expressly stated otherwise. In addition, the singular forms “a”, “an” and “the” are to be interpreted as “at least one”, thus also possibly comprising a plurality of entities of the same kind, unless expressly stated otherwise. It will be further understood that the terms “includes”, “comprises”, “including” and/or “comprising”, specifies the presence of stated features, actions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, actions, integers, steps, operations, elements, components, and/or groups thereof. A single unit such as e.g. a processor may fulfil the functions of several items recited in the claims. The mere fact that certain measures or features are recited in mutually different dependent claims, illustrated in different figures or discussed in conjunction with different embodiments does not indicate that a combination of these measures or features cannot be used to advantage.