GB2078077A - Method of and apparatus for milking - Google Patents

Abstract

A method of milking for removing milk from a teat disposed in a teat rubber, in which milk is sucked from the gland opening of the teat into a milk-delivery system by a reduced pressure which is maintained in a teat cup to act on a lower portion (27) of the teat (17), whilst an upper portion (25) of the teat (17) is acted upon alternatingly by increased pressure and by reduced pressure. <IMAGE>

Description

SPECIFICATION Method of and apparatus for milking This invention relates to a milking method for removing milk from a teat which is disposed in a teat rubber, in which milk is sucked from the gland opening of the teat into a milk-delivery system by a reduced pressure which is maintained in a teat cup, and apparatus for carrying out the milking method.

The milking machines which are generally employed nowadays operate with a periodic change between a suction phase and a relief phase. The milk is withdrawn from the teat during the suction phase.

In such an arrangement, the reduced pressure in the teat cup acts on the teat and draws the milk therefrom. In the subsequent relief phase, the teat rubber firmly embraces the teat so that the reduced pressure in the teat cup cannot apply its effect to the teat. The men skilled in this art prefer a mode of operation which involves a change in pressure between atmospheric pressure and a reduced pressure. This is done so as simultaneously to use the reduced pressure required for conveying the milk, for applying pressure to the teat.

Also known is a milking method in which the lower portion of the teat is acted upon with a continuous reduced pressure in a pulse-free manner, whereas the upper portion of the teat is acted upon in a pulsating manner with a change in pressure between a reduced pressure and atmospheric pressure.

Although, in regard to enhancing the milk yields, it has been found advantageous for the lower portion of the teat to be acted upon with a continuous reduced pressure in a continuous pulse-free manner, and for the upper portion of the teat to be acted upon in a pulsating manner of operation, nonetheless, in regard to the milk yields which can be achieved, the known method which operates with the change in pressure between a reduced pressure and atmospheric pressure still does not show optimum results.

A disadvantage which has been found is that there is a permanent pressing force between the teat and the teat rubber, throughout the entire performance of the method. Only the intensity of the pressing force on the surface of the teat is changed when there is a change between reduced pressure and atmospheric pressure.

In a series of recent scientific studies of mechanical milking, the fact that the teat cup climbs up the teat during the milking operation towards the base of the teat has been related to the milking yields which in part are still unsatisfactory. This upward movement of the teat cup essentially occurs because, during the change in pressure, the cling force between the teat cup and the teat changes and the teat changes in shape during the suction phase.

There are indications that a teat cup which moves upwardly towards the base of the teat causes the cow discomfort which can give rise to a tendency in the animal to withold the milk. There is thus a need for an improved milking method and apparatus which provides an improvement in the adhesion force between the teat and the teat cup, and stimulation of milk ejection.

According to the invention, there is provided a method of milking for removing milk from a teat disposed in a teat rubber, in which milk is sucked from the gland opening of the teat into a milk-delivery system by a reduced pressure which is maintained in a teat cup to act on a lower portion of the teat whilst an upper portion of the teat is acted upon alternatingly by increased pressure and by reduced pressure.

This milking method has advantages from many points of view.

The change between an increased pressure above atmospheric on the one hand and a reduced pressure below atmospheric on the other hand provides good stimulation in respect of milk ejection, in comparison with conventional milking installations. This improvement in stimulation can be seen from the amount of residual milk which remains in the teat well or chamber. In very good milking installations which operate in a conventional manner, the residual amount of milk is about 15%, and is higher in the normal case. In comparison, when milking by hand, the milk can be produced, down to about 7% residual milk. The application of pressure in machine milking produces conditions which substantially equate to those of hand milking, in regard to stimulation.Because of the change between pressure and relief, which is applied to the teat by the person milking the cow, he produces very good milk extraction results with very low amounts of residual milk.

These considerations are put to use in milking installations in which the entire teat is embraced by the teat rubber during the relief phase. The teat rubber is acted upon by an increased pressure for the period of about one minute. This application of an increased pressure is intended to cause stimulation of milk ejection, which is similar to hand milking. As the teat rubber collapses severely under this pressure actuation however, the pressure phase can be maintained only over the period of one minute, in the previously known milking methods. Subsequently, the pressure has to be rapidly reduced so that the suction phase can be started.

In comparison, according to the invention, the lower portion of the teat is continuously subjected to reduced pressure so that the application of pressure in the upper portion of the teat can be maintained throughout the pressure phase. In this way, the method according to the invention gives conditions which substantially equate to those of hand milking.

The stimulation effect which is achieved with the method according to the invention is of a corresponding nature. The amount of residual milk, at from 10% to 12%, is markedly below that which is to be found in conventional installations. It has a tendency constantly decreasing towards attaining 7%.

The method according to the invention achieves a considerable step towards achieving the milking yield which can be achieved by hand milking. The stimulation effect is produced on the one hand by the improved massage action of the teat, which is produced by the application of pressure. On the other hand, however, the pressure change always takes its effect at the same position of the teat in the upper region thereof. As recent test results in particular have shown, the part of the teat which is the most important from the point of view of stimulation of the cow is the upper part which is adjacent to the base of the teat. Because the teat cup is firmly seated in place, the point of engagement of the change in pressure on the teat surface does not change during the milking operation.

The applicants have thus succeeded in developing a milking method, by means of which on the one hand the milk yields which can be obtained come very close to those which are produced in hand milking. The action of increased pressure on the base of the teat extends over the entire pressure phase and is therefore substantially more intensive than could be the case with teat rubbers which enciose the teat over its entire length. On the other hand however, the continuous reduced pressure ofthe milk suction discharge system acts on the lower portion of the teat. The continuous reduced pressure provides a continuous and uniform discharge of milk so that the reverse flow effect is effectively counteracted.

Besides the good milking output, the method of the invention also provides a high level of safety for preventing the transmission of germs, in particular mastitis.

The adhesion of the teat cup to the surface of the teat is improved by the application of pressure.

When the increased pressure is released, the pressure conditions obtaining in the pulse chamber run through a number of transition stages; although the cow experiences such stages as being a relief of pressure, such stages actually give a considerable improvement in the rubbing action between the teat rubber on the one hand and the surface of the teat on the other hand, in comparison with the conventionally found conditions in which, afterthe pulse chamber has been vented with atmospheric pressure, a reduced pressure is produced in the pulse chambers. This enhancement in the cling effect of the teat rubber to the teat has the effect on the one hand that the teat cups do not slip off the teat during the suction phase.On the other hand, the improvement in the cling action provides that the teat cup fits to the teat in a relatively uniform and constant manner, thereby preventing the teat cup from climbing up the teat towards the base thereof. This therefore substantially simulates the conditions which arise in hand milking and in which the hand of the milker always grips the teat at the same position, irrespective of the degree of milk discharge.

In accordance with a preferred embodiment of the invention, control of the pressure pulses is effected, in respect of their magnitude, in groups or individually for each animal. The pressure application step provides for very good control of the pressure conditions in the region of the teat rubber. This good control permits both the pressure frequency and also the magnitude of the pressure to be adapted to the conditions which are experienced by each animal individually as being the optimum ones and which can be ascertained in objective form by determining the amount of residual milk. These requirements which are individual to a given animal are based on the physical properties in regard to length, diameter and other configuration oftheteat, and in the physical area, in regard to the application of pressure changes, which is found to be agreeable.Individual control of the pressure change makes it possible to cause enhanced stimulation of the cow. On the other hand for example a rough teat surface requires shorter pressure phases than a smooth teat surface on which the teat rubber can move more rapidly and with less friction, than on a rough teat surface.

Further details of the invention will be apparent from the detailed description hereinafter and the accompanying drawing which shows a preferred embodiment of the invention by way of example.

The drawing shows a diagrammatic view of a milking installation for performing the method according to the invention.

A milking installation which is suitable for carrying out the method according to the invention essentially comprises a milk-discharge system 1 and a system 2 which controls and produces the change in pressure between an increased pressure and a reduced pressure. The milk discharge system 1 essentially comprises a reduced pressure producing means 3, a vacuum conduit 4, a milk collecting container 5, a milk conduit 6, a connecting member 7, a milk hose 8 and a teat cup 9. Formed in the teat cup 9 is an internal space or chamber 10. The chamber 10 is connected by way ofthe milk hose 8 to the connecting member 7 which in turn is connected by way of the milk conduit 6 to the milk collecting container 5. The reduced pressure required for extracting the milk is produced in the milk discharge system 1 by the reduced pressure producing means 3, by way of vacuum conduit 4.

The system 2 for producing and controlling the change in pressure essentially comprises an increased pressure producing means 11, the reduced pressure producing means 3, the control means 12, the connecting conduit 13 to the increased pressure producing means, the connecting conduit 14 to the reduced pressure producing means, and the pulse hose 15. The control means 12 is connected by way of the pulse hose 15 on the one hand to the pulse chamber 16 in the teat cup 9 and on the other hand, by way of the connecting conduit 13, to the increased pressure producing means 11 and, by way of the connecting conduit 14, to the reduced pressure producing means 3. By way of the control means 12, a teat 13 which extends within the chamber 10 can be acted upon with a pressure change between an increased pressure on the one hand and a reduced pressure on the other hand.

The teat cup 9 for ca rrying out the method according to the invention is substantially in the form of a rigid portion 18 and a resilient portion 19 with an air inlet 20 and a lip 21. The teat 17 which projects into the internal chamber 10 is surrounded in its lower portion 26 by the rigid portion 18 and, in its upper portion 25, by the resilient portion 19. The upper portion of the teat cup 9 fits in a sleeve 22 whose upper end portion 23 projects into a corresponding edge portion 24 of the resilient portion 19. Provided between the sleeve 22 and the teat cup 9 is the pulse chamber 16 which is in communication with the pressure producing means 3 and 11 by way of the pulse hose 15.

A sufficient reduced pressure is produced in the system 1 by the reduced pressure producing means 3. After the teat cup 9 is fitted to the teat 17, the reduced pressure can be extended into the teat cup 9. This causes the teat 17 to be acted upon by the reduced pressure so that the flow of milk can begin.

When the control means 12 is set in operation, the pulse chamber 16 is connected either to the increased pressure producing means 11 or to the reduced pressure producing means 3 so that either an increased pressure or a reduced pressure can be produced in the pulse chamber 16. When the pulse chamber 16 has an increased pressure therein, the resilient portion 19 clings to the teat 17 and embraces it in the manner of a sphincter. This causes the teat cup 9 to be firmly held on the surface of the teat 17 ofthe animal to be milked. At the same time, the teat 17 experiences a massage action which is intended to produce stimulation which is produced by the teat 17 being subjected to a pressure force by the resilient portion 19. At the same time, the circulation of blood in the teat 17 is maintained.This is essentially achieved by the air which passes in through the air inlets 20. The air passes into the chamber 10 and there forms a flow of air between the teat 17 and the inside wall surface of the chamber 10. With a massage action adapted in this manner, the mechanical milking operation in this phase will substantially simulate a natural milking operation. On the other hand, udder diseases for example due to regional overloading are prevented.

For the purpose of initiating the flow of milk, a reduced pressure is produced in the pulse chamber 16, by way of the control means 12. This reduced pressure causes the resilient portion 19 to be lifted away from the wall of the teat 17. In this condition, because of the pressure difference which obtains between the chamber 10 and the ambient air, as between the reduced pressure and atmospheric pressure in the chamber 10, the teat cup 9 is held on the teat 17. In this condition also, because of the reduced pressure in the chamber 10, a flow of air is formed along the walls of the teat. Because it acts as an air cushion, the air flow serves to maintain the circulation of blood within the teat 17. At the same time, it is used to accelerate the discharge flow of milk so that a reverse spray towards the tip of the teat is prevented in this manner.

Very good control in respect of the pressure conditions in the region ofthe resilient portion 19 is possible by virtue of the application of pressure. This makes it possible for the mode of procedure of the method to be substantially influenced in dependence on individual animals. This can be done for example by the milking operation being specifically adapted to each animal, by means of a suitable programme. A computer can be used for this purpose, for controlling for example the control means 12 on the basis of the input data. The control action can relate both to the magnitude of the pressure and the pulse length.

The adhesion of the teat cup to the teat is improved and an additional stimulation effect is produced by means of the differentiated pressure control action. The teat 17 is embraced in its upper portion 25 by the resilient portion 19, by virtue of an increased-pressure pulse which is introduced into the pulse chamber 16, in such a way that the air flowing into the arrangement through the air inlet 20 is restricted. In addition, the constriction applies a strong massage effect to the teat 17, which is substantially similar to the massage effect of hand milking.

Claims (9)

1. A method of milking for removing milk from a teat in a teat rubber, in which milk is sucked from the gland opening of the teat into a milk-delivery system by a reduced pressure which is maintained in a teat cup to act on a lower portion ofthe teat whilst an upper portion of the teat is acted upon alternatingly by increased pressure and by reduced pressure.

2. A milking method according to claim 1, in which the magnitude of the alternating pressure pulses is controlled individually.

3. A milking method according to claim 1 or claim 2, in which the alternating pressure pulses are controlled in duration in accordance with requirements which are individual to the animal being milked.

4. A milking method according to any one of claims 1 to 3, in which the teat is acted upon with an alternating pressure pulse frequency such as to optimize the milk ejection reflex of the animal being milked.

5. A milking method according to any one of claims 1 to 4, in which the pressure conditions in a pulse chamber surrounding the teat cup are controlled, via a central control means, by a computer which is programmed with data individual to the animal being milked.

6. A method of a milking according to claim 1, substantially as hereinbefore described with reference to the accompanying drawing.

7. Apparatus for carrying out the method of mi 1k- ing according to claim 1, including at least one teat rubber and teat cup for removable location on an animal teat, means for exerting and maintaining a reduced pressure on a lower portion of a teat in the rubber, and means for exerting alternating increased pressure and reduced pressure pulses on an upper portion of the teat in the rubber whilst the reduced pressure is maintained on the lower portion of the teat.

8. Apparatus according to claim 7, including a computer, programmable with data individual to an animal to be milked, for controlling pressure conditions in a pulse chamber surrounding the teat cup.

9. Apparatus for carrying out the method of mi 1k- ing according to claim 1, substantially as hereinbefore described with reference to the accompanying drawing.