the invention will be described with reference to the first embodiment of an apparatus generally designated by reference numeral 1 for automatically milking a dairy animal , such as a cow , wherein one teat cup 2 is shown in fig1 . the measures of the inventive method will be set out clearly in the description with respect to the apparatus . moreover , the invention will be explained in further detail by way of example with reference to a limited number of specifically mentioned milking parameters . however , it will be appreciated that also other milking parameters than those described in the claims , may be used . a person skilled in the art will thus understand that by experimental research , variation of a milking parameter can be measured during the milking process . such deviation may then be used , possibly processed by a mathematical formula , for determining at least partially the deactivation threshold . teat cup 2 shown in fig1 may be automatically connected and disconnected to or from a teat of a cow by means of a milking robot which is not shown in the figures . the milk yielded per udder quarter by means of teat cup 2 may be supplied via its own separate milk line 4 to a corresponding milk quantity meter or milk glass 3 . a discharge line 5 of milk glass 3 is coupled to a line 7 extending to a bulk milk cooling tank 6 . as known , apparatus 1 further comprises a pulsator system 8 for each teat cup 2 . the vacuum line 9 for the pulsator system 8 is connected in a usual manner to a vacuum pump with a balance tank . in an obliquely downwardly extending portion of milk line 4 is a milk flow meter 10 for establishing the start of milk flow and for determining the value of the milk flow during milking , or in other words , during the time when the teat cup is active . said milk flow meter 10 operates in this example on the basis of the creation by a milk flow of an electric connection between two electrodes . the tilted position of milk flow meter 10 prevents milk from remaining between the electrodes , or in other words , prevents a small quantity of milk from being present between the electrodes which would of course result in a milk flow being permanently observed . in the region of milk flow meter 10 milk line 4 has preferably such a diameter that irrespective of the milk flow present therein , the milk line is always completely filled . in milk line 4 there is also included a temperature meter 11 for establishing the milk temperature . the milk temperature is a good measure for the body temperature ; with sick cows , such as cows affected by mastitis , the body temperature is higher than normal . in milk glass 3 a conductivity meter 12 is disposed for determining the electric conductivity , for example , for establishing mastitis or another infectious illness . said conductivity meter 12 comprises a reservoir with electrodes for measuring the electric conductivity of the milk present in the reservoir . at each new milk flow the milk present in the reservoir is replaced . when the milk is affected , then an increased electric conductivity is established . because for each new milk flow there is observed in the beginning a small increase of the electric conductivity , it is also possible to establish the start of a milk flow by using this mastitis sensor instead of milk flow meter 10 or in addition thereto . the outgoing signals s 1 , s 2 and s 3 of the respective meters 10 , 11 and 12 are supplied to a computer 13 in which the information from these meters will be further processed , as will be set forth hereinafter , and may be made visible on a display screen 14 . between line 5 and line 7 is further a three - way valve 15 for discharging the milk flow from a quarter affected by mastitis of the udder of the cow to a waste tank 16 . when , on the basis of the information communicated by computer 13 , the farmer decides to discharge milk to the waste tank 16 and provides for that purpose an appropriate command to computer 13 , three - way valve 15 is switched over by means of a signal s 4 supplied by computer 13 . computer 13 may transmit this signal s 4 automatically to the three - way valve 15 . according to the invention computer 13 may determine on the basis of the data from milk flow meter 10 the starting time when the milk flow begins and preferably store said staring time ( temporarily or permanently ). also the momentary milk flow as measured by milk flow meter 10 may be stored by computer 13 . from these data computer 13 continuously determines the average milk flow . determination of the average milk flow may begin at the moment when the milk flow starts or , for not taking into account the first measurements which may usually contain noise or deviating values , when a predetermined period of time after the start of the milk flow , such as after a period from ten to fifty seconds , has elapsed . it is noticed that by storage is meant that the computer retains the data , at least as long as necessary for processing them . for storing the data , computer 13 comprises one or more memories 17 ( in the embodiment shown only one memory is depicted for the sake of simplicity ). computer 13 comprises a processing member 18 suitable for applying a mathematical function to the value of the average milk flow . as a result of the mathematical function a threshold milk flow average is obtained . based on desires of the operator , a suitable function may be selected . however , based on long research it has been learned that for a quick deactivation of the teat cup , the function of dividing by three is highly appropriate irrespective of the individual cow . it has been further learned that for a deactivation which is not “ quick ” the function of dividing by five is highly appropriate irrespective of the individual cow . computer 13 further comprises a comparator 19 for comparing the momentary milk flow with the calculated threshold milk flow average . when the comparison indicates that the momentary mil flow equals or is lower than the calculated threshold milk flow average ( functioning as a deactivation threshold ), computer 13 supplies a signal s 5 controlling the deactivation of teat cup 2 . for example the deactivation may be due to the fact that signal s 5 controls pulsation system 8 in such a manner that the vacuum is removed from teat cup 2 . based on extensive research it has also been discovered that it is possible to describe the average milk flow produced by cows in certain milk flow ranges , and to allocate a certain threshold milk flow value to each of those milk flow ranges . such milk flow ranges and corresponding threshold milk flows are stored in memory 17 of computer 13 . an example of such ranges is represented hereinafter in table i . comparator 19 of computer 13 compares the measured average milk flow with the ranges stored in the memory , and computer 13 determines the corresponding threshold milk flow . when the momentary milk flow equals or is lower than the threshold milk flow , the computer supplies signal s 5 for deactivation of teat cup 2 . as a threshold milk flow value also other predetermined threshold values may be used such as those based on historical data . the signals issued by the meters 11 and 12 during milking may be averaged over a certain period of time , such as over twenty - four hours , or over a number of milking runs or a combination of both . as the cow will be milked several times per day , this average value may each time be calculated as a progressive average . conductivity meter 12 thus determines the momentary electric conductivity of the milk obtained and computer 13 ensures the storage of the average , historical electric conductivity of the teat based on historical data . this average , historical electric conductivity , provides an indication about this parameter for that teat of that particular cow . when comparator 19 of computer 13 compares the momentary electric conductivity with the average , historical electric conductivity which is stored in memory 17 of computer 13 , the difference between these values can be determined by computer 13 . of course , an animal identification system which is well known in the art may be used which , for the sake of simplicity is not detailed further . when the difference exceeds a certain preset value , the relevant teat may be infected , and computer 13 may issue relevant signals for taking the necessary measures . in particular it is of importance for the health of the relevant cow that the teat is milked in another manner than when a normal conductivity value is detected . for that purpose the means , in the present case pulsation system 8 , for deactivating the teat cup 2 is put into operation by computer 13 at a point of time depending on the measured average milk flow and the difference in electric conductivity . in particular computer 13 applies a mathematical function both to the value of the average milk flow and to the difference in electric conductivity for obtaining a so - called compensated threshold milk flow average . it is then preferred that the function is such that with a raised conductivity the deactivation takes place at an other point of time than usual , whereby the teat will be milked longer . after long research it has been learned to be advantageous that , when the deviation is greater than 10 %, a function consisting in multiplying the average milk flow by ten and in dividing it by the difference in electric conductivity ensures that the deactivation of the teat cup takes place at a point of time which is appropriate with respect to udder health . it goes without saying that the average milk flow may also be used in combination with other milking parameters for placing the means for deactivating the teat cup into operation . when for example during milking temperature meter 11 issues a value which clearly deviates from the relevant average value , that it is outside a certain tolerance range around the average value , this may be an indication of illness of the cow . computer 13 may then be programmed so that in this case teat cup 2 is immediately deactivated and disconnects from the teat . moreover , computer 13 may provide a warning signal to the farmer . in the embodiment shown in fig2 apparatus 1 comprises four teat cups 2 . each of teat cups 2 can be connected to a teat of a cow . of the milk produced by each of the teat cups 2 the milk flow is determined by milk flow meter 10 , temperature by temperature meter 11 , and electric conductivity by conductivity meter 12 . these data are used according to the embodiment described with reference to fig1 . however , in the embodiment of fig2 computer 13 determines the teat ( teat cup 2 ) from which at one point of time the milk has the lowest electric conductivity . for every other teat ( teat cup 2 ) computer 13 determines the deviation from the electric conductivity of the milk produced by that other teat relative to the lowest conductivity of the milked obtained from the teat producing the milk with the lowest conductivity . in a manner analogous to that of the above - described embodiment the difference in the conductivity of the milk between the teats ( teat cups 2 ) may be an indication of an infection in at least one of the teats . like in the embodiment of fig1 it is then advantageous that means for deactivating the teat cup are put into operation by the computer at a point of time depending on the average milk flow and the difference in electric conductivity . it has appeared that as a function , the same function , that is multiplying the average milk flow by ten and dividing it by the difference in electric conductivity , can be used advantageously . besides the means for deactivating the teat cup , apparatus 1 may comprise a milking robot such as is well known in the art , said milking robot comprising means for automatically connecting and disconnecting the teat cups . these means may be identical to or integrated into the means for deactivating the teat cups . however , the computer is preferably suitable for determining a period of time from deactivation of the teat cup and for placing the means for disconnecting the teat cups into operation when the period of time has reached a certain time threshold value . the time threshold value is preferably adjustable , a range between approximately two seconds and approximately fifteen seconds appearing to be advantageous . it will be appreciated that in some cases it is advantageous not to deactivate the teat cup immediately when the momentary value of the milking parameter equals or is lower than the threshold milking parameter value , but only when this situation occurs during a period of time , said period of time being adjustable such as between approximately two seconds and approximately nine seconds . in particular the period of time amounts to three seconds . average values may be determined from further signals which may be deduced from combinations of signals issued by several sensors . in particular by the milk flow meter in combination with the quantity of milk per milking run collected in milk glass 3 , signals may be deduced being a measure for the milk velocity or the milk yield or both . also the value of these signals may be averaged . the mentioned averaging processes are carried out in computer 13 and will all relate to a particular animal or a particular group of animals or a particular period of time , or a combination thereof . the signals issued by one or more sensors during milking of separate animals and having a value deviating from this average value , may always be an indication that something is wrong with the health of the relevant teats . such an indication may be provided by computer 13 on an attention list , that is , both be made visible on display screen 14 of computer 13 and be printed . in addition , an alarm may be provided such as in the form of control lights to be disposed on the equipment or via the mobile telephone of the farmer . although we have disclosed the preferred embodiments of our invention , it is to be understood that it is capable of other adaptations and modifications within the scope of the following claims .
a method of automatically milking a dairy animal , in particular a cow . the method comprises : a ) the step of activating the teat cup for milking the teat ; b ) the step of measuring a milking parameter during milking the teat during step a ) for obtaining a value of the milking parameter , and c ) the step of deactivating the teat cup when a deactivation threshold has been reached . the deactivation threshold is determined at least partially with the aid of the value of the milking parameter . a device for automatically milking a dairy animal , in particular a cow . said device is provided with means for activating the teat cup for milking a teat of the dairy animal , means comprising a milking parameter for measuring a milking parameter during milking the teat for obtaining a value of the milking parameter , means for deactivating the teat cup , and means for generating a threshold signal indicating that a deactivation threshold has been reached . the deactivation means are put into operation with the aid of the threshold signal , the means for generating the signal indicating a deactivation threshold generating the signal at least partially with the aid of the value of the milking parameter .