GB2142812A - An automatic animal feeder - Google Patents

Abstract

Animal feeding equipment has a plurality of individual feed stations (11) at which animals can feed, and a common feed dispensing station (22) operable to dispense predetermined metered quantities of feed to each station (11). A sensor (16) at each feed station (11) detects if a previously supplied metered quantity has been taken and signals to a central control unit which operates to control the dispensing station (22) to allow a subsequent metered quantity of feed to be dispensed to that station providing it does not exceed a predetermined maximum quantity within a given unit of time, which maximum quantity varies with time according to a predetermined development programme. <IMAGE>

Description

SPECIFICATION An automatic animal feeder The present invention relates to an automatic animal feeder, and particularly although not exclusively to an automatic system for feeding warm milk substitute to calves.

The present invention is applicable to the feeding of any liquid feed to any kind of animals although it will be specifically described hereinafter, without loss of generality, to a system adapted for feeding calves.

Various systems for feeding milk substitutes to calves are known. Such systems act to dispense powdered milk into a mixing vessel into which warm water is fed, and mixing of the milk powder is effected usually by means of a high speed stirrer, following which the prepared milk substitute is supplied along lines to one or two outlets in a pen containing up to twenty animals. Often in use, such systems supply feed continuously to the outlets, and the animals, all contained in one pen, take turns in drinking. For this reason even if the feed is mixed warm, it is eventually supplied cold to the animals, and for this reason the milk substitute is often acidified by the addition of acids to improve clotting time which is necessary in preventing scouring of the calves.The known feeding systems have a number of disadvantages, among which the most significant is the provision of only one or two teat outlets for a large number of animals.

Because of this the feed must be supplied continuously in order to enable all animals to feed as and when they can, and no check can be made on which animal is taking a large quantity and which animals may be 'bullied' and unable to take as much as they might want, particularly since competitive suckling may encourage the stronger animals to drink even when they may otherwise not have done so thereby restricting the feed intake of weaker animals. It is important to note that the health of ruminants is very closely tied up with their appetite and one of the earliest signs that an animal is not in perfect health is loss of appetite. In such multiple suckling environments, however, it is impossible to monitor feed intake accurately so that this early warning of ill health is not available.

A critical stage in the development of all mammals is the change-over period from a diet consisting mostly of milk or milk substitutes to a 'solid' diet. Weaning from the milk diet takes place once the animals can successfully cope with a solid diet and it is important from an economic point of view that the animal be weaned as early as possible since the milk substitute is relatively more expensive per pound of live weight gain in the animal than the solid food. However, if weaning is attmpted before the animal is properly prepared for it, weaning stress and a substantial weight loss or 'set-back' can occur thereby detracting from the advantage of the early weaning.When using a pen containing up wards of ten or more animals, however, it is impossible to wean them individually and con sequently group weaning has to take place which may be deleterious to some of the animals if they are not entirely ready. On the other hand, by waiting for the slower animals to catch up a considerable wastage of feed in feeding the more advanced animals is experi enced.

The present invention seeks to provide an automatic animal feed system which is capable of overcoming the disadvantages out lined above. The present invention also seeks to provide automatic animal feed apparatus capable of providing milk substitute at blood heat where previous systems have been forced to feed the milk substitute cold be cause of the difficulty of maintaining the feed at the required temperature whilst avoiding bacteriological contamination.

According to one aspect of the present invention automatic animal feeding apparatus comprises a plurality of individual feed sta tions at which animals can feed, a common feed dispensing station operable to dispense predetermined metered quantities of feed to each station, and sensor means at each feed station for detecting if a previously supplied metered quantity has been taken from that feed station, and means for supplying a fur ther metered quantity to the feed station when the previously supplied metered quantity has been taken.

The present invention allows for the possi bility of individual penning or group penning with feed from a common feed station. By providing individual feed stations for indivi dual animals the difficulty of 'bullying' is avoided. Of course, individual feed stations require individual pens for the animals, but because of the open lattice nature of the hurdles from which the pens may be formed the animals can be as aware of the presence of other animals as ehen they are in a com mon pen. Moreover, by providing relatively small individual doses the possibility of filling the distribution network with warm milk sub stitute in excess of requirements is avoided because each metered dose must be taken before the system will provide another and the metered doses travel through the system leav ing very little residue.Preferably each feed station includes a container for liquid feed and a teat through which feed can be drawn by suckling animals. The container must be suffi ciently large to contain a metered dose so that the pipework distributing the feed to the feed st station can remain empty except when the liquid is actually passing through it from the distribution station to a feed station. Conveni ently the feed stations are fed by gravity from the dispensing station along respective feed conduits. Although this requires a larger number of individual tubes and a greater length of pipework than the use of a common delivery conduit, it makes it possible for each feeding station to be supplied independently of the others from the dispensing station so that the feed supply to each station can be closely matched to the requirements of the particular animal at that station.Calves having different requirements and at different stages of their development can then be placed in any pen without requiring a predetermined growth pattern or movement of the animals from pen to pen in order to vary feed quantities.

If warm milk or milk substitute is fed to the feed stations it is important that it should be maintained at a certain temperature within close tolerances. For this purpose it is preferred that the feed stations themselves include subsidiary heaters for maintaining the temperature of the feed for at least a predetermined period after delivery to the feed station.

Such heaters may be in the form of a surrounding belt or 'muffle' incorporating resistance heater wires connected to a suitable source of electricity. The presently preferred heating means comprises a ducted warm water system however, with suitable heat exchangers at the feed stations conveniently such that exchangers may be in the form of coils of tubing, for example copper tube surrounding the feed container at the feed station.

Likewise, each feed station preferably incorporates a sensor for detecting if a preceding dose has been taken, this being determined by detecting the liquid level within the feed station container, for example by means of a float having an associated magnetic switching device or by means of a suitable diaphragm switch of known type. This will then send a signal to the distribution system indicating that the minimum liquid level has been reached and that a further metered dose can be supplied to that particular feed station if this is within the predetermined programme requirements.

The feed dispensing station preferably includes a plurality of input chambers each communicating with a respective feed conduit leading to a respective feed station. The feed dispensing station may be provided with an input conduit, a header tank receiving liquid feed from the input conduit, means for detecting the level of liquid in the header tank operable to control the supply of liquid fed thereto, and means for sequentially distributing metered doses of liquid feed from the heater tank to the said feed conduit input chambers.

In a preferred embodiment of the invention the feed conduit input chambers are disposed in a ring and the distributing means of the feed dispensing station comprises a radially extending hollow arm the radially inner end of which is formed as a liquid-receiving chamber in communication with the output from the said header tank and the radially outer end of which is formed as a dispensing nozzle which passes sequentially over the feed conduit input chambers. In operation, the said hollow radially extending dispensing arm of the distribution station is indexed angularly by means of a stepping motor drive system.In order to ensure that the indexed positions are correctly achieved there are preferably provided position sensing means operable to detect the stopping position of the hollow radially extending arm at one of its predetermined indexed positions, means being provided for adjusting the position of the arm with respect to the said predetermined index position when it is stationary thereat.

According to a further aspect of the present invention there is provided a mixing apparatus suitable for use with the automatic feed system, at which a liquid feed is made up from powder and a liquid, preferably water, the mixing at the mixing station being effected by pumping the liquid and powder repeatedly around a closed path including a chamber into which the powder and liquid are introduced prior to mixing. Preferably the mixture is pumped around the close circuit by a magnetically coupled pump. It has been found that by rapidly pumping the mixture around a closed circuit in this way adequate mixing of the powder in the liquid can be achieved without frothing and at a very high rate.

Conveniently the mixing chamber is an upwardly open mixing vessel and the ingredients to be mixed are withdrawn at a low level and returned at a higher level of the vessel during the mixing process. Withdrawal of the mixture for distribution can take place at any convenient point in the mixing path, although a position immediately 'downstream' of the pump, at or adjacent its delivery outlet is preferably used.

Conveniently the upwardly open mixing vessel is pivotally mounted for turning movement about a substantially horizontal axis for tipping the contents thereof. Such tipping is not required for the delivery of mixed powder, but rather for a cleaning function where it may be required to dump the cleaning mixture. The conduits constituting the said closed mixing path are preferably flexible tubes connected between the fixed supports and the tippable vessel in such a way as to permit such tipping movement without requiring disconnection. A cleaning cycle can thus readily be performed by introducing a cleaning liquid in place of the mixing liquid, and by closing off the powder input. Such cleaning cycles are required at regular intervals in order to prevent bacterial contamination of the apparatus. Although in the preferred embodiment heated water is delivered to the mixing vessel, this latter is preferably also provided with heating means for raising or maintaining the temperature of the feed during mixing. The mixing vessel heater may be in the form of a band surrounding the vessel and containing electrical resistance heater wires, or alternatively may be a heat exchanger adapted for transferring heat from a ducted fluid circuit to the mixing vessel. Like the feed station container heater this may be formed as a coil of tubing around the vessel, carrying the heat transfer fluid of the system.

The present invention also comprehends a powder measuring and delivery suitable for use in the automatic feed system of the present invention, such device being operable to receive a predetermined volume of powder from a hopper and deliver it to the mixing vessel. The powder measuring and delivering device preferably comprises a metering cylinder having an opening in the curved wall thereof, the metering cylinder being mounted with its axis substantially horizontal and being turnable about its axis within a cylindrical housing the curved wall of which closely surrounds the metering cylinder and has a first opening above a horizontal median plane thereof and a second opening below such plane, and a hopper the outlet of which communicates with the said first opening in the said housing cylinder.

Such a metering cylinder is preferably closed at one end by a removably mounted plug having locating means for determining its axial projection into the metering cylinder, which projection determines the volume of the metering cylinder itself. Such a plug can be interchanged with plugs of different axial length in order to vary the metering volume of the cylinder whereby to adjust the apparatus for different mixing consistencies.

The present invention also comprehends automatic animal feed apparatus in which each animal is individually penned and supplied with metered quantities of liquid feed by an automatically operated supply mechanism which is programmed to supply each animal with a plurality of doses of feed up to a certain maximum, which maximum is varied from feed to feed in dependence on the animal's past feeding pattern, the control means operating wholly independently for each animal.

The present invention can be put into practice in various ways although one specific embodiment of the invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic diagram illustrating the general arrangement of the apparatus of the present invention; Figure 2 is a schematic sectional side view of a part of the powder dispensing and mixing system; and Figure 3 is a schematic and perspective view of the powder dispenser shown in Figure 2.

Referring first to Figure 1 the apparatus shown is designed to mix powdered milk substitute with warm water and to deliver it to a plurality of individual feed stations to be withdrawn through teats by respective individual animals. For the sake of clarity only one feed station, generally indicated 11 is illustrated in the drawing although it will be appreciated that using the system to be described below anything up to forty different feed stations may be provided. The feed station 11 comprises a feed container 1 2 which in the example illustrated comprises a commercial available plastics bottle mounted by a bracket 1 3 to a suitable fixed part of an animal stall at a level convenient for calves to feed directly therefrom.For this purpose the container 1 2 is provided with an outlet teat 14 projecting from the container. In communication with the main volume enclosed by the chamber is a diaphragm switch 1 6 which acts to detect when the liquid reaches a predetermined level within the feed container 1 2. When the liquid within the feed container 12 reaches this level the diaphragm switch 1 6 commutes to provide a signal on an output line 1 8 leading to a central control unit 1 9 which controls the entire operation of the syste The feed container 72 is enclosed in an insulating layer 1 9 which acts to maintain the liquid within reasonable tolerance values of the required temperature for the animals to be fed.For example, the required temperature for -calves if 102 F. The feed container 1 2 is also provided with a visible indicator, such as a light emitting diode, generally indicated 20 which is controlled by the system to flash when milk above the required minimum level is present in the container 1 2. This flashing indicator is intended to provide the operator with an indication that the container is in use and also to act as a visual stimulus to the animal that milk is being supplied to the teat, with a view to training the animal when the feed is available.Milk or milk substitute is supplied to the feed container 1 2 along a plastics tube 21 which is inclined at a gradient of approximately 1 in 40 down to the feed container 1 2 from a feed distribution station generally indicated 22. This feed distribution station comprises a support table 23 to which a plurality of feed conduit input chambers 24 are fitted in a ring, each chamber 24 having an outlet connection 25 leading to a respective feed delivery tube 21 for directing feed dispensed into the chamber 24 to a respective feed station container 1 2. Apart from its position in the circle of chambers 24, and the fact that it connects to a respective delivery conduit 21 leading to a different feed container 12, all the chambers 24 and couplings 25 are identical.

Liquid feed is dispensed to the chambers 24 in turn by a hollow rotating dispensing arm 26 which has a radially outer dispensing nozzle 27 and is formed at its radially inner end with an upwardly open funnel 28 which receives the delivery ends of two tubes 29,30 respectively leading from a feed cistern 31 and a water cistern 32 which will be described in greater detail below.

The rotating arm 26 is mounted on a spindle 33 driven to rotate about its axis by a drive transmission 34 connected to the output shaft 35 of a single revolution motor 36. The motor 36 is energised by pulses from the controller to make one complete revolution before stopping, following which a further input pulse is required for energisation. The drive transmission 34 has a transmission ratio selected such that for each revolution of the motor 36 the output shaft 33 turns through a fraction of 21r determined as the reciprocal of the number of feed conduit input chambers 24 provided in the ring. Thus, in the illustrated example, if there are forty input chambers 24 the shaft 33 will turn through one fortieth of 360", namely 9 for each revolution of the motor 36.This movement will index the arm 26 from a position centralised over one chamber 24 to a position centralised over the next adjacent chamber 24. A mechanical indexing mechanism 1 5 acts on a wheel 1 7 to which the arm 26 is attached to ensure that accurate indexing movements take place each time the controller 1 9 issues a signal to cause the arm 26 to turn to a new position. Milk substitute or milk is supplied to the milk system 31 along a milk delivery duct 39 under the control of a float switch 38 which actuates a pair of valves 40,41; namely to open the valve 40 when the float switch is open, and close the valve 40 when the float switch detects that the liquid level has reached a predetermined value.The valve 41 is positioned in a closed mixing circuit comprising a tube 42 leading from the valve 41 to a mixing vessel 43, and a tube 44 leading from the bottom of the mixing vessel 43 to a circulation pump 45 the delivery output of which leads to a T-junction 46, one arm of which leads to the valve 40 and the other arm of which leads to the valve 41. A drain pipe 94 leads from the feed tube 39 to the mixing vessel 43 to prevent feed from stagnating in the tube 39 when the pump 45 is disconnected by closure of the valve 40. This pipe 94 is made of small diameter to present higher resistance to flow than the tube 39.

In operation milk powder and water are delivered to the mixing vessel 43 and circulated by the pump 45 through the mixing path comprising the tube 44, the T-junction 46, the open valve 41 and the tube 42. Such a mixing circuit acts thoroughly ti distribute the particles of milk powder throughout the body of liquid without causing frothing so that a very rapid mixing rate can be achieved. The pipes 42 and 44 are flexible allowing the vessel 43 to be tipped about a tilt axis 47 for discharge through an open top 48 for reasons which will be described in greater detail below. The vessel 43 is provided with an insulation 49 to maintain the liquid temperature in the vessel.The mixing vessel 43 receives powder from a powder dispensing system generally indicated 51 and shown in more detail in Figures 2 and 3, and the powder path from the dispensing system is enclosed by a casing 50.

The powder dispensing system 51 comprises a main hopper 52 secured to backing support plates 53a and a support panel 53b.

The hopper 52 has a substantially rectangular upper portion and a lower portion defined by front and back parallel walls and two inclined walls 54, 55. The front wall 56 is transparent to allow visual examination of the contents.

Within the lower part of the hopper, defined by the inclined walls 54, 55 is a hopper agitator generally indicated 57 having a plurality of spring arms 58 projecting radially from a stem and extending over an arc of 105 (only some of which are illustrated in the drawings). The lower wall of the hopper has an opening 59. A powder sensor 95 is provided in the lower part of the inclined wall 55 to provide a signal confirming the presence of powder in the hopper and to provide an inhibit signal to switch off the system in the event that an absence of powder is detected. This signal can also trigger an alarm.

The sensor itself may be a diaphragm switch exposed to the powder through an opening in the hopper wall.

The powder metering unit further comprises two plates 60, 61 held spaced apart by adjustable columns 62. The upper plate 60 has a sliding plate gate valve 63 and the lower plate 60 has a similar sliding plate gate valve 64. Respective actuators 65, 66 operate the sliding plates 63, 64 to open or close associated openings in the plates 60, 61. A cylindrical chamber 67 between the plates defines the metered quantity of powder dispensed into the mixing vessel 43 through the sleeve 50. This cylindrical chamber 67 is interchangeable with cylinders of different volumes to vary the mixture concentration assuming a given volume of water is supplied to the mixing vessel at each mixing operation.

As can be seen in Figure 1, water is supplied to the mixing vessel 43 along a duct 73 leading, via a valve 88, and a tube 85 from an output from a water heater 75 of a known electrically heated instant water heater. A level sensor is provided to ensure the pressure of an adequate water level and a temperature sensor 80 is provided to ensure that the water at the output of the heater does not exceed a predetermined selected temperature. An output from the heater is also taken via a pipe 93 leading via a control valve 81 to the water cistern 32 from which it can pass via the duct -30 and the funnel 28, to the receptacles 24 for supplying warm water in place of warm milk or milk substitute when controlled to do so by the control circuit acting on the valve 81.

The central control unit 1 9 operates to control all of the operation of the apparatus described above. Milk substitute is supplied to the individual feed containers 12 at predetermined intervals and the quantity of feed supplied is determined according to a predetermined programme stored in the control circuit memory and in dependence on the amount of feed being taken by the animal. The indexed position of the arm 26 can always be determined so that the individual feed container 12 being supplied at any one time is known. This information is used by the control circuit 19 to determine the maximum number of metered doses of milk or milk substitute which can be supplied to that particular feed container 12 at each feed or in any given period of time.

The arm 26 stops in position over the receptacle whilst a metered quantity of feed is dispersed to the receptacle 24, and then moves on to the next dispensing position. The number of doses or metered quantities of feed supplied to any one receptacle 24 is detected by the control circuit and counted. Before a further metered quantity of milk or milk substitute can be supplied to an input chamber 24, therefore, the two conditions that the maximum number of doses has not been exceeded and the previous dose has been withdrawn from the feed station 12 must be met.

When the preselected permitted quantity of feed has been withdrawn, warm water is supplied via the cistern 32 at all times to allow the calves to drink between meals without sucking on a dry teat, and this warm water also helps to flush through the system pipework to prevent a build up of milk so that bacterial contamination can be inhibited.

A special function tank 82 fed from the water heater 75 via a branch pipe 85 and a tap 86 is provided. This tank can be fed by hand with any additional material such as feed supplement or medicaments, which can be introduced into the water supplied to the mixing vessel 43 along the line 73 by operation of a valve 87 and, perhaps, also by cooperating operation of a valve 88 to the waterline 73. This special function tank may be used to supply medication or for use when weaning the calves. This tank may also be used to contain a cleaning solution when it is not required for other purposes, which solution is fed to the mixing vessel 43 under the control of the central control unit in a predetermined automatic cleaning cycle which takes place between feeding cycles and which ensures that mixed feed does not remain in the pipes for an excessively long time.It is possible, for this purpose, for one of the containers 24 of the feed distribution station to be connected directly to a drainage outlet and the arm 26 to be controlled so that the feeding vessels 1 2 are not supplied with the cleaning solution unless the operator or supervisor is present to ensure that the vessels 1 2 are filled and emptied for cleaning purposes without the calves drinking the cleaning solution.

Weaning may take place in accordance with one of several different schemes. The most orthodox method is to ration the calf by progressively restricting the permitted total daily volume of milk fed, and this can be programmed automatically by the system. In a second scheme, the concentration of milk in the milk substitute may be gradually reduced, which results in a given volume of the feed becoming generally less palatable and less nutritious. The overall objective is to reduce to zero the intake of milk feed over a period of time, usually in the region of ten to fourteen days. At the same time it is vital that the calves are monitored and encouraged to eat more solids thereby ensuring a minimum set back in growth and condition during this critical phase.

These and other weaning methods which may be devised may be used with the apparatus of the present invention by suitable control and or adjustment of its operating parameters together with suitable programme control by the electronic control circuit.

Although a single penning system has been described, that is one on which each feed container 12 is assigned to a single animal, it is envisaged that a system in which a plurality of animals may feed from one feed container may be provided within the scope of this invention: in this case the control system will need to incorporate an arrangement by which individual animals can be identified so that their individual consumption can be monitored.

The control unit 1 9 for the equipment maintains a check on each station and provides an output to a display panel (not shown) indicating the proportion of the maximum ration withdrawn within each 24 hour period from each station so that an immediate visual check on the progress of each animal can be readily made.

Claims (24)

1. Animal feeding equipment having a plurality of individual feed stations at which animals can feed, a common feed dispensing station operable to dispense predetermined metered quantities of feed to each station, and sensor means at each feed station for detecting if a previously supplied metered quantity has been taken from that feed station, and means for supplying a further metered quantity to the feed station when the previously supplied metered quantity has been taken.

2. Animal feeding equipment as claimed in Claim 1, in which each feed station includes a container for liquid feed and a teat through which feed can be drawn by suckling animals.

3. Animal feeding equipment as claimed in Claim 1 or Claim 2, in which the feed stations are fed by gravity from a dispensing station along respective feed conduits.

4. Animal feeding equipment as claimed in any of Claims 1 to 3, in which warm feed is supplied to the feed stations, which latter include subsidiary heaters and/or insulation for maintaining the temperature of the feed for at least a predetermined period after delivery to the feed station.

5. Animal feeding equipment as claimed in Claim 4, in which the heater is in the form of a surrounding layer having electrical resistance heating conductors.

6. Animal feeding equipment as claimed in any preceding Claim, in which there are provided sensor means at each feeding station openable to provide a signal indicating the presence of a residual amount of a metered quantity of feed previously supplied to the station.

7. Animal feeding equipment as claimed-in Claim 6, in which the sensor means is a float having a magnetic switching device associated therewith.

8. Animal feeding equipment as claimed in any preceding Claim, in which the feed dispensing station includes a plurality of input chambers each communicating with a respective feed conduit leading to a respective feed station.

9. Animal feeding equipment as claimed in Claim 8, in which the feed dispensing station has an input conduit, a header tank receiving liquid feed from the input conduit, means for detecting the level of liquid in the header tank operable to control the supply of liquid feed thereto and means for sequentially distributing metered quantities of liquid feed from the header tank to the said feed conduit input chambers.

10. Animal feeding equipment as claimed in any preceding Claim, in which the feed conduit input chambers are disposed in a ring and the distributing means of the feed dispensing station comprises a radially extending hollow arm the radially inner end of which is formed as a liquid-receiving chamber in communication with the output from the said header tank and the radially outer end of which is formed as a dispensing nozzle which passes sequentially over the feed conduit input chambers.

11. Animal feeding equipment as claimed in Claim 10, in which the said hollow radially extending dispensing arm of the distribution station is indexed angularly and the indexed positions are determined by an indexing mechanism.

1 2. Animal feeding equipment as claimed in Claim 11, in which there are provided position sensing means operable to detect the stopping position of the hollow radially extending arm at one of its predetermined indexed positions, means being provided for adjusting the position of the arm with respect to the said predetermined indexed position.

1 3. Animal feeding equipment as claimed in Claim 11, in which the liquid feed is supplied to the distribution station from a mixing station at which the liquid feed is made up from powder and a liquid such as water or an aqueous mixture, the mixing at the mixing station being effected by pumping the liquid and powder repeatedly around a closed path including a chamber into which the unmixed powder and liquid are introduced prior to mixing.

14. Animal feeding equipment as claimed in Claim 1 3 in which the chamber is an upwardly open mixing vessel and the ingredients to be mixed are withdrawn at a low level and returned at a higher level of the vessel.

1 5. Animal feeding equipment as claimed in Claim 14, in which the upwardly open vessel is pivotally mounted for turning movement about a substantially horizontal axis for tipping the contents thereof, the conduits constituting the said closed mixing path being flexible tubes connected between fixed supports and the tippable vessel in such a way as to permit such tipping movement without requiring disconnection.

16. Animal feeding equipment as claimed in Claim 14 or Claim 15, in which the mixing vessel is provided with heater means for raising or maintaining the temperature of the feed during mixing.

1 7. Animal feeding equipment as claimed in Claim 1 6 in which the mixing vessel heater is in the form of an insulating belt surrounding the vessel and containing electrical resistance heater conductors.

18. Animal feeding equipment as claimed in any of Claims 1 3 to 17, in which powder is delivered to the mixing vessel from a hopper by means of a powder measuring and delivery device operable to receive a determined volume of powder from a hopper and to deliver it to the mixing vessel at each cycle of operation of the device.

1 9. Animal feeding equipment as claimed in Claim 17, in which the powder measuring and delivery device comprises a metering chamber having upper and lower closure gates operable in phase opposition, the path from the hopper to the mixing vessel via the metering chamber being entirely enclosed.

20. Animal feeding equipment as claimed in any of Claims 13 to 19, in which the feed delivery system draws liquid feed from the closed mixing circuit.

21. An automatic animal feed system in which each animal is individually penned and supplied with metering quantities of liquid feed by an automatically operated supply mechanism which is programmed to supply each animal with a plurality of doses of feed up to a certain maximum, which maximum is varied from feed to feed in dependence on the animals past feeding pattern, the control means operating entirely independently for each animal.

22. Animal feeding equipment having a plurality of feed stations at which animals can feed, a common feed dispensing station operable to dispense metered quantities of feed to each station, and sensor means at each feed station for detecting if a previously supplied metered quantity has been withdrawn from that feed station, and control means for determining whether a further metered quantity of feed is to be supplied to a feed station when the feed station sensor indicates that the previously supplied metered quantity has been withdrawn.

23. Animal feeding equipment as claimed in Claim 22, in which the control means acts to supply successive metered quantities of feed up to a predetermined maximum quantity within a given period of time according to a predetermined maximum feeding programme.

24. Automatic animal feed equipment substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.