Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
tO95/23501 2~ 5 PCT/DE95/00101
Mechanical Milking Process
The present invention relates to a mechanical milking process
in which suction of a predetermined strength is appl ied to the
5 interior space within an udder cup that is applied to a teat,
and the cup rubber is caused to pulsate at a predet~rm; ne~
frequency and strength by alternately evacuating and re-
pressurizing an intermediate space within the udder cup and,
with the udder cup in place, during a stimulation phase prior
10 to the main milking phase, the maximal pulse suction is
reduced for a predetermined time so that the teat is
stimulated .
A process of this kind is known, for example, from DE 30 47
15 579 C2; in this particular process, the stimulation phase
lasts for a predetermined time, which means that the results
of this phase cannot be checked. Since, however, each breed
of milk-producing cattle and each beast will react
differently, depending on the stage of lactation it is in, all
20 that will be possible is a compromise solution that is applied
to all such beasts. In practice, it has been found that such
a process can cause a negative reaction in cattle because of
over-stimulation. Such effects are particularly marked when a
beast is at the beginning stage of lactation or if, because of
25 manual stimulation of the udder in the pre-milking stage and
when cleaning the udder, the milker allows machine stimulation
218~o5
WO95/23501 PCT/DE95/00101
time to act on the beast's udder in addition, and without any
reduction. Such excessively protracted periods of stimulation
then interfere with the beast's milk production.
5 A similar problem is encountered at the end of lactation, in
the event of a stimulation phase that is too brief. In this
phase, a beast needs greater stimulation, so that a longer
stimulation phase i~ required in order to secure good milk
extraction and short milking times.
DE 36 21 666 C2 describes a machine milking process in which
the stimulation time is adjusted as a function of the beast's
stage of lactation. Here, too, however, one proceeds from
f ixed parameters that do not take into account the particular
15 stimulation requirement of an individual animal or the manual
stimulation provided by the milker.
It is the task of the present invention to create a process
with which the stimulation requirements of individual beasts
2 o are taken into account .
This problem has been solved in that the stimulation phase i8
divided into a pre-stimulation phase, in which no significant
quantity of milk is extracted, and a subsequent control phase,
25 during which changing the pressure cycle in the intermediate
space within the udder cup reduces the intensity of the
W095/23501 ~184~ PCT/DE95/00101
pressure on the teat by the cup rubber in such a way that milk
is extracted. The main milking phase begins as soon as the
flow of milk exceeds a predetGrm;n~d threshold value.
5 The duration of the pre-stimulation phase is so selected that
there is no possibility of over-stimulation of beasts that are
to be milked. During this phase, stimulation can be provided
in the known way. During the following control phase, the
pressure exerted by the cup rubber on the beast's teat is
10 reduced without any change in the nature of the stimulation
phase. This, in conjunction with rising pressure within the
udder, means that milk can be extracted. When this occurs,
the increasing intensity of the flow of milk is an indication
that the stimulation has been effective, and it also makes it
15 possible to determine the optimal duration of the stimulation
phase for each beast.
It is in no way sufficient to change to the normal milking
rhythm in order to measure the intensity of the milk flow once
20 the pre-stimulation phase has ended for then, because the
complete opening of the cup rubber that then ensues, the teat
duct opens because of the existing suction and there is an
unrestricted extraction of the cistern milk present in the
udder. When this happens, beasts that are easy milkers, which
25 have a sphincter muscle that is easy to open, achieve a short-
~ived milk ~low in excess of 2 ~g/minute, despite a lack of
WO95/23501 21~6~5 PCT/DE95/~0~1
r~linocc for milking. At any rate, after a little while the
flow of milk ceases, and it is thus unsuitable for indicating
the results of the stimulation phase.
5 In one advantageous embodiment, modification of the pressure
cycle is brought about by prolonging the repressurization
phase in the intermediate space within the udder cup. The
length of the reprecsurization phase is to be selected in such
a way that the intensity and the magnitude of the pressure
10 that builds up in the intermediate space within the udder cup
differs greatly from the values that are effective during pre-
stimulation. This means that a lower pressure is exerted on
the tip of the teat by the cup rubber in the control phase so
that, given sufficient pressure within the udder, the natural
15 resistance of the sphincter muscle within the teat can be
overcome and milk can pass into the milking machine. When the
milk flow exceeds a certain level, the stimulation phases is
concluded and the main milking phase begins.
20 In another advantageous configuration, the repressurization
phase is so selected that the intermediate space within the
udder cup is evacuated as soon as atmospheric pressure is
reached. Thus, full pressure only acts on the teat for a very
brief period, which means that throughout the whole of the
25 pulse cycle the teats are subjected mainly to a lower
pressure, so that milk can be extracted during this time.
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WO95/23501 PCT/DE95/00101
Extraction of milk can also be made easier in that the
duration of the repressurization phase prevents the pressure
from rising to atmospheric values.
5 The pre-stimulation phase should last for at least 20 seconds.
During this time, a stimulus that results in the excretion of
oxcitocin to a threshold value that is characteristic for an
individual beast is provided. Only then can the control phase
and, following this, the main milking phase begin. Unless
10 this is done, there is a danger that an irrelevant milk flow
value that does not indicate that the beast is ready for
milking will be measured. In the event that sufficient manual
pre-stimulation has been provided by the milker, the machine-
base control phase can be started.
In order that over-stimulation is always avoided, the duration
of the pre-stimulation phase should amount to 35 seconds at
most .
20 Since beasts that are easy milkers can also reach a specific
intensity of milk flow even without ade~uate stimulation, it
has been found practical to establish a threshold value of 300
ml/minute for milk flow. It may be appropriate to increase
this threshold to at least 500 ml/minute. Amongst other
25 things, this will be dependent on the different ways milking
.
W095/23501 21~ PCT/DE95/00101
facilities can be designed, e.g., with high or low-level milk
1 ines .
The duration of the overall stimulation phase should be
5 limited in order to avoid an inappropriately long stimulation
phase in the event that the threshold value is not reached.
The present process will be explained in greater detail below
on the basis of the drawings appended hereto. These drawings
10 show the following:
Figure 1: The pressure cycle in the pre-stimulation phase;
Figure 2: the pressure cycle in the control phase, with
atmospheric pressure;
5 Figure 3: The pressure cycle in the control phase without
atmospheric pressure.
Figures 1 to 3 show the curve for the suction "Pu" in the
intermediate space wlthin the udder cup plotted against time
20 "t. "
As can be seen in Figure 1, the pulse cycle in the pre-
stimulation phase comprises the evacuation phase "a, ", the
suction phase "b, " the repressurization phase "c, " and the
25 pressurization phase "d. " The pressurization phase "d" is
v~ry d~stinct. For this reason' the cup rubber scarcely
W095/23501 2 ~ 8 4 ~ 0~ PCT/DE95/00101
opens, 60 that no milk is extracted. The beast is stimulated
in the desired manner by the high pulse repetition rate.
The pressure cycle curve in the control phase, which is shown
5 in Figure 2, differs from that of the stimulation phase by the
fact that the repressurization phase "c" is prolonged by a
value by which the time for the pressurization phase "d" is
sharply reduced. This means that atmospheric pressure is only
reached briefly. This results in a longer open period for the
10 cup rubber, so that the desired milk flow is made possible.
If the repressurization phase "c" prolonged even more, as is
shown in ~igure 3, the pressurization phase "d" is eliminated
and atmospheric pressure is not reached. The pressure on the
15 teat is thus greatly reduced, thereby making extraction of the
milk easier.
