GB1562193A

GB1562193A - Animal feeding apparatus

Info

Publication number: GB1562193A
Application number: GB40984/75A
Authority: GB
Original assignee: RJ Fullwood and Bland Ltd
Current assignee: RJ Fullwood and Bland Ltd
Priority date: 1976-10-07
Filing date: 1976-10-07
Publication date: 1980-03-05

Description

(54) IMPROVEMENTS IN AND RELATING TO ANIMAL FEEDING APPARATUS (71) We, R. J. FULLWOOD & BLAND LIMITED, a British Company, of Ellesmere, Salop, SYl2 9DG, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention relates to animal feeding apparatus.

The invention provides animal feeding apparatus which comprises means defining a stall for an animal, a closure member movable between an open position in which an animal can enter the stall and a closed position in which an animal within the stall is enclosed, the arrangement being such that the closure member is urged towards the open position, the apparatus further comprising a manger in the stall, and means arranged to be operated by the animal to close the closure member on entering the stall and moving towards the manger and to allow the closure member to open on moving away from the manger.

By providing a manger in a stall having a closure member, arranged to be operated by an animal on entering the stall and moving towards the manger, it is possible to arrange for one animal at a time to move up to the manger and to consume feed within the closed stall without interference from any other animal.

With the herd of animals it is often desired to give each animal an exact amount of feed. Advantageously, the feeding apparatus comprises means for delivering a predetermined amount of feed to the manger in response to a control signal. With this arrangement it is possible for each animal to consume a predetermined amount of feed without the risk of one animal pilfering the ration of another. Preferably, the arrangement is such that the amount of feed delivered by the feed delivering means to the manger in response to the control signal is adjustable.

It is also often desired to supplement the feed of some of the animals and not others.

In the case of cows, for example, it is usual to feed all the cows during milking but the average milking time is only about 6 minutes and this is sometimes not long enough for the cows to consume the desired amount.

Thus, the animals to whom it is wished to give an additional amount of feed may be provided with identification means to distinguish them from the other animals not to receive additional feed, and the animal feeding apparatus is advantageously provided with means for sensing the said identification means on an animal in the stall and for giving the control signal, to which the means for delivering feed to the manger is responsive, upon sensing the said identification means. With this arrangement it is possible to carry out selective feeding in which an animal bearing such identification means, for example, a metal article worn around the neck, enters the stall and eats additional rations delivered to the manger in response to a signal from the sensing means undisturbed by other animals. An animal without such identification means on entering the stall will, however, receive no additional rations. The metal articles may be such as can be secured around the necks of the animals by means of plastics chains or some other fastening means which would break readily should it get caught up on anything, avoiding the risk of strangulation by a metal chain.

Two or more of the feeding apparatus according to the invention may be provided within the same animal enclosure, the sensing means of each apparatus being arranged to sense a different kind of identification means. For example, the sensing means of one apparatus may be arranged to sense ferrous metal articles and the sensing means of a second apparatus within the same enclosure may be arranged to sense non-ferrous articles, for example, brass, some of the animals being provided with ferrous metal articles and some with non-ferrous articles. This enables the feeding time of the herd to be shortened but at the same time ensures that one animal cannot obtain feed from each apparatus but only from the one for which it carries the associated identification means. With this arrangement it is possible for each different apparatus to deliver an amount of feed in response to its control signal which is different from that delivered by the or each other apparatus, so that animals bearing different kinds of identification means can be fed different amounts.

It is also possible for the sensing means of one apparatus to be capable of sensing different kinds of identification means and to give a control signal which varies in accordance with the kind of identification means sensed in order to vary the amount of feed (if any) delivered to the manger.

The means for sensing the identification means or the means for delivering feed to the manger is advantageously provided with time delay means operable to ensure that, after feed has been delivered to the manger, further feed is not delivered by the feed delivering means for a predetermined length of time. This ensures that an animal that has already consumed feed from the manger cannot obtain a further quantity immediately after consuming the first quantity. The time delay means is advantageously such as to ensure an interval of at least about 7 to 8 minutes between deliveries and preferably an interval within the range of from 12 to 15 minutes, and may be adjustable to vary the length of time during which it ensures that further feed is not delivered to the manger by the feed delivering means.

Advantageously, the means arranged to be operated by the animal to close the closure member as the animal moves towards the manger and to allow it to open as the animal moves away from the manger comprises means which is movable between a position in which it projects into the path of movement of the animal to the manger and in which it allows the closure member to be in its open position, and a position out of the path movement in which it causes the closure member to move to its closed position, the said means being movable from the former position to the latter position by pressure exerted by the animal on the said means as it moves towards the manger. Preferably, the said means is urged towards the said former position and is arranged to be maintained in the said latter position by the body of the animal while it is at the manger. The said means is preferably arranged to move between the said former and latter positions by rotation about a vertically-extending axis, and may be in the form of a pivotal arm. The closure member, which is preferably in the form of a gate, is advantageously movable between its open and closed positions by rotation about a further vertically-extending axis and the closure member is preferably mechanically linked to the said means.

The means for delivering feed to the manger advantageously comprises a hopper for a supply of feedstuff and means for conveying feed from the hopper to the manger, which may be a screw conveyor but is preferably a vibratory conveyor. for example, a vibrating tray. The time during which the vibratory conveyor is operational to convey feed to the manger in response to the control signal may be adjustable so as to vary the amount of feed delivered.

Animal feeding apparatus constructed in accordance with the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side view of the apparatus with a part removed; Figure 2 is a plan of the apparatus: and Figures 3 and 4 are circuit diagrams.

Referring to the accompanying drawings, and initially to Figures 1 and 2 a stall, indicated generally by the reference numeral 1, for a cow is defined by a pair of side railings 2 and 3, respectively, made from galvanised iron tube and a feed delivery device, indicated generally by the reference numeral 4, which closes one end of the stall. At the other end, a closure member in the form of a gate 5 is hinged to the side railing 2 by hinges 6 and 7, respectively, so as to be pivotally movable about a vertical axis Al. The gate 5 is movable between an open position as shown in solid lines in Figures 1 and 2 in which the cow can enter the stall 1 and a closed position as shown in broken lines in Figure 2 in which a cow within the stall is enclosed.

The hinge 6 is provided with a torsion spring 8 which is arranged to urge the gate into the open position. The railings 2 and 3 are at a distance of approximately I m from each other so that a cow in the stall cannot lie down or turn round and the railings are sufficiently high that the cow can only enter throught the open end of the stall.

The feed delivery device 4 comprises a housing 9 containing a hopper 10 for feedstuff which can be provided with a weather-proof cover if the apparatus is standing in the open. A tray 11 situated beneath the hopper outlet is arranged to be vibrated, in operation, for a predetermined length of time which is adjustable within the range of from 5 to 50 seconds by a vibrator unit 12 which is actuated by a low voltage signal of predetermined frequency given by an operating mechanism which is indicated generally by the reference numeral 13 and which will be described in more detail hereinafter. The vibrator unit 12 is mounted on a rigid platform 14 within the housing 9.

The tray 11, when vibrating, dispenses feed from the hopper 10 into a manger 15. A sensing unit 16 may be mounted on a supporting arm 17 secured to the housing 9 so as to project in front of, and slightly below the upper edge of, the manger 15, as shown, or the sensing unit may be mounted on the outer surface of the face 15a of the manger. The sensing unit 16 is arranged to sense the presence of ferrous metal articles (not shown) on cows entering the stall I and to send a signal to the operating mechanism 13 on sensing the presence of such an article. Alternatively, the sensing unit 16 may be one that senses the presence of brass articles. The ferrous metal or brass articles may take the form of a few, say three, links of chain made from that material suspended from a plastics chain worn around the neck of the cow so that the metal links hang down in front of the cow. The plastics chain is arranged to break easily if caught on anything so as to reduce the risk of strangulation of the cow.

An arm 18 is pivotally mounted at one end to the side railing 2 so as to be movable about a vertical axis A2 from a position in which it projects across the stall 1 (as shown in solid lines in Figure 2) into the path of movement of a cow to the manger 15 blocking a cow's access to the manger to a position alongside the railing 2 (as shown in broken lines in Figure 2) allowing a cow access to the manger. The portion of the arm 18 remote from the railing 2 is curved, the centre of curvature lying between the arm and the feed delivery device 4 when the arm is blocking access to the manger, and strengthening strut 19 is provided across the curved portion.

As can be seen from Figure 2, the arm 18 and the gate 5 are connected by a linkage, indicated generally by the reference numeral 20, which is such that when the gate 5 is in the open position the arm 18 is projecting across the stall 1 into the path of movement of a cow to the manger 15, and when the gate 5 is in its closed position the arm 18 is lying alongside the railing 2 allowing access to the manger. As the gate 5 is urged into its open position by the torsion spring 8, the arm 18 is also urged to take up its position extending across the stall 1. The arm 18 is at a height such that as a cow enters the stall her body presses on the arm causing it to move out of her way and maintain it alongside the railing 2 while she is at the manger. The linkage 20 comprises a linking member 21 which is rigidly secured at one end to the arm 18 and at the other end pivotally connected to a tubular connecting member 22. The connecting member 22 extends back towards the gate 5 and at its end remote from the linking member 21 is slidably mounted on one end portion of a rod 23. On the opposite end of the rod is slidably mounted a short tube 24 pivotally secured to a further link member 25 which is, in turn, rigidly connected to the gate 5 at the hinge 7. A cushion spring 26, which acts in compression, is arranged to urge the tube 24 and the connecting member 22 away from each other and is arranged to prevent jarring of the linkage and consequent damage.

Referring now to Figure 3, this shows the circuit diagram for the vibrator unit 12 and operating mechanism 13. A vibrator coil 12' of the vibrator unit 12 is connected on one side to a 10 volt A.C. supply by a lead 27 and on the other side to an earth line 28 through a gate-controlled switch THI. When the gate-controlled switch TH 1 is rendered conducting by a positive pulse applied by a lead 29 to its gate, the 10 volt A.C. supply is applied across the vibrator coil 12', energising the coil and causing vibration of the tray 11 and delivery of feed to the manger 15.

This positive pulse is supplied by an NE555 integrated timing circuit ICI having eight terminal pins numbered 1 to 8, respectively. This integrated circuit ICI is capable of producing accurate time delays and in this instance is connected as a monostable multivibrator, it being triggered from its stable state to its unstable state by a pulse to pin 2 and reverting to its stable state after a period of time determined by the values of Rl, R2 and Cl connected to pins 6 and 7. In this case Rl is a variable resistor, its maximum value being 100KQ, R2 is a 10KQ resistor and Cl is a 220of capacitor, the period of time taken for ICI to revert to its stable state after having been triggered being within the range of from 550 seconds and being adjustable by virtue of the variable resistor R 1. The integrated circuit ICI is connected to a power supply by means of connections to pins 8 and 1 of the circuit, the pin 8 being connected by a lead 30 to a positive supply line 31 and the pin 1 being connected to the earth line 28. The positive supply line 31 is connected to a 15 volt A.C. supply which is rectified by a diode D1 and reduced to 12 volts by a Zener diode Zl and resistor R3. Capacitors C2 and C3 are each connected between the positive supply line 31 and the earth line 28 to remove ripple from the D.C. supply.

Suitable connections to pins 4 and 5 of the circuit ICI provide facilities not required in this application, so that pin 4 is merely tied to the positive supply line 31 and the pin 5 is connected to the earth line 28 through a capacitor C4 of . 11F. The output of the circuit is delivered at pin 3 to which the lead 29 is connected. When the integrated circuit ICI is triggered by a pulse to pin 2, a pulse will be delivered from the output pin 3 of a width dependent on the time during which the circuit ICI is in its unstable state and this pulse in turn renders the switch THI conducting for that length of time. The height of the pulse is determined by the values of R4 and R5, R4 in this case being 390Q and R5 being IOKQ.

The output pulse from pin 3 of ICI is differentiated by a capacitor C5 of . 001of and a resistor R6 of 27KQ to give positive and negative spikes which are fed by a lead 32 to pin 2 of a further NE555 integrated timing circuit IC2 also connected as a monostable multivibrator, the circuit IC2 being triggered on receiving the negative spike at its pin 2. The time during which IC2 is in its unstable state is determined by the values of resistor R7 and capacitor C6 which in this instance are 1.2my and 470,uF, respectively, so that IC2 will, on being triggered by a negative spike fed to pin 2, be in its unstable state for a period of approximately 15 minutes. As with ICI, pin 8 of IC2 is again connected to the power supply line 31 and pin 1 is connected to the earth line 28, the functions supplied by suitable connections to pins 4 and 5 again not being used in this application, and pin 4 being connected to the positive supply line 31 and pin 5 being connected by a capacitor C7 of .l,uF to the earth line 28.

The output from pin 3 of2 is fed by a line 33 into one input terminal numbered 11 of a NOR gate IC3', into which is also fed the output from pin 3 of IC1 via a lead 34 connected to an input terminal numbered 12 of the NOR gate IC3'. Thus the NOR gate IC3' effectively adds in time the output pulses from IC1 and IC2, the output at the terminal numbered 14 of the NOR gate IC3' falling when the circuit ICI is triggered to its unstable state and remaining low while the circuit ICI is in its unstable state and the vibrator coil 12' is energised. Since, as soon as the circuit ICI reverts to its stable state, the circuit IC2 is switched into its unstable state, the output from the NOR gate IC3' remains low for a further period of about 15 minutes while the circuit IC2 is in its unstable state. At the end of this period when the circuit IC2 reverts to its stable state the output from the NOR gate IC3' rises.

The output from the NOR gate IC3' is fed by a lead 35 to one input numbered 6 of a four input NAND gate It3", one further input numbered 5 of which is tied to the lead 35 and a second further input numbered 7 of which is tied to the positive supply line 31 thus taking no part in the logical operation. The fourth input numbered 9 of the NAND gate is connected to the sensing unit 16, the voltage at that input being normally low but rising in the presence of a ferrous metal article worn by an animal. The output at terminal 10 from the NAND gate is normally high and is connected through a diode D2 by leads 36 and 37, respectively, to the trigger pin 2 of the circuit ICI, which is triggered as the output from the NAND gate IC3" falls. This will only happen when both the circuits ICI and IC2 are in their stable states so that the input at terminal 6 is high and the input at terminal 9 rises because of the arrival of an animal wearing a ferrous metal article in the region of the sensing unit 16. When the circuit ICI is triggered the output from the NOR gate IC3' falls and the output from the NAND gate IC3" rises again. Since the output from the NOR gate IC3' remains low while the circuits ICI and IC2 are in their unstable states, the output from the NAND gate IC3" cannot fall again and trigger the circuit ICI for a period of approximately 15 minutes after energisation of the vibrator coil 12'.

The NOR gate IC3' and the NAND gate IC3" may either be two separate packages or may be combined in a single package IC3 (indicated in broken lines in Figure 3) in which case they may have common power supply connections to the supply line 31 and the earth line 28.

A switch Sl is connected on one side by a lead 36 to the positive supply line 31 and on the other side to the earth line 28. The lead 38 also serves to connect the leads 36 and 37 so that when the switch Sl is closed pin 2 of the circuit ICI is earthed, triggering ICI and activating the vibrating tray 11 and thus overriding the time delay for calibration purposes.

The A.C. power supplies of 10 volts and 15 volts, respectively, are provided from mains supply by a transformer, the circuit of which is shown in Figure 4. The transformer is located remote from the feeding apparatus at a position where the cows have no access to it.

In operation, the cows that are to be fed rations by means of the apparatus are provided with a few links of a ferrous metal chain suspended from a plastics chain worn around the neck. The hopper 10 is filled with suitable feedstuff. The torsion spring 8 causes the gate 5 to be in its open position and the arm 18 to project across the stall 1 blocking access to the manger 15 as shown in solid lines in Figure 2.

A cow entering the stall 1, in order to gain access to the manger 15 presses against the arm 18 pushing it out of her way back into the position shown in broken lines in Figure 2. At the same time, the gate 5 will be caused to close by virtue of the linkage 20 against the action of the torsion spring 8 and will be maintained closed while the body of the cow maintains the arm 18 in its position alongside the railing 2.

If the cow in the stall 1 is wearing the ferrous metal links, this will be detected by the sensing unit 16. The vibrator unit 12 will be energised so as to vibrate the tray 11 for a predetermined length of time set by the integrated circuit ICI, causing feed to be delivered to the manger 15 for that time. If the cow in the stall I is not wearing the ferrous metal links, no feed will be delivered to the manger 15.

The stall 1 when closed by the gate 5 protects a cow feeding in the stall, allowing her to eat her rations without interference or pilfering from other cows. The arrangement of the apparatus is such that a cow cannot reach the manger without actuating the arm 18 and thus closing the gate 5.

After a cow wearing the ferrous metal links has finished feeding, or if the cow does not have the links and therefore has no reason to remain in the stall 1, she backs out of the stall pushing her rump against the gate 5 and at the same time releasing the arm 18 so that the gate 5 is allowed to open under the action of the torsion spring 8 and the arm 18 is caused to return to a position blocking access to the manger 15.

The amount of feed delivered in response to the signal from the sensing unit 16, which depends upon the time during which the vibrator unit 12 vibrates the tray 11, can be varied by adjusting the value of R1, which gives a range of from 5 to 50 seconds for the vibration time of the tray 11.

When the vibrator unit 12 has finsihed vibrating the tray 11 in response to the signal from the sensing unit 16 it cannot be reactuated for a period of about 15 minutes set by the circuit IC2. This prevents a cow from immediately obtaining a further quantity of feed. This period can be adjusted by varying the value of R7.

One or more further feeding apparatus may be installed within the same animal enclosure as the feeding apparatus described above, the one or more further apparatus being identical with that feeding apparatus except that the sensing unit of each apparatus is arranged to sense identification means other than ferrous metal articles. For example, a second feeding apparatus may be installed having a sensing unit arranged to sense brass articles on an animal, which can be in the form of a few links of a chain attached to a plastics chain as hereinbefore described. This enables the feeding time of the herd to be shortened but at the same time ensures that one cow cannot obtain feed from each apparatus but only from the one for which it carried the associated identification means.

WHAT WE CLAIM IS: 1. Animal feeding apparatus which comprises means defining a stall for an animal a closure member movable between an open position in which an animal can enter the stall and a closed position in which an animal within the stall is enclosed, the arrangement being such that the closure member is urged towards the open position, the apparatus further comprising a manger in the stall and means arranged to be operated by the animal to close the closure member on entering the stall and moving towards the manger and to allow the closure member to open on moving away from the in anger.

2. Animal feeding apparatus as claimed in claim 1, which comprises means for delivering a predetermined amount of feed to the manger in response to a control signal.

3. Animal feeding apparatus as claimed in claim 2. wherein the arrangement is such that the amount of feed delivered by the feed delivering means to the manger in response to the control signal is adjustable.

4. Animal feeding apparatus as claimed in claim 2 or claim 3, which comprises means for sensing identification means on an animal in the stall and for giving the control signal, to which the means for delivering feed to the manger is responsive upon sensing the identification means.

5. Animal feeding apparatus as claimed in claim 4, wherein the sensing means is arranged to sense a metallic article on an animal which forms the said identification means.

6. Animal feeding apparatus as claimed in claim 4 or claim 5, wherein the sensing means is capable of sensing different kinds of identification means and to give a control signal which varies in accordance with the kind of identification means sensed.

7. Animal feeding apparatus as claimed in any one of claims 2 to 6, wherein there is provided time delay means operable to ensure that, after feed has been delivered to the manger, further feed is not delivered by the feed delivering means for a predetermined length of time.

8. Animal feeding apparatus as claimed in claim 7, wherein the time delay means is such as to ensure an interval of at least about 7 or 8 minutes between deliveries.

9. Animal feeding apparatus as claimed in claim 8, wherein the interval is within the range of from 12 to 15 minutes.

10. Animal feeding apparatus as claimed in any one of claims 7 to 9, wherein the time delay means is adjustable to vary the length of time during which it ensures that further feed is not delivered to the manger by the feed delivering means.

Il. Animal feeding apparatus as claimed

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. the cow maintains the arm 18 in its position alongside the railing 2. If the cow in the stall 1 is wearing the ferrous metal links, this will be detected by the sensing unit 16. The vibrator unit 12 will be energised so as to vibrate the tray 11 for a predetermined length of time set by the integrated circuit ICI, causing feed to be delivered to the manger 15 for that time. If the cow in the stall I is not wearing the ferrous metal links, no feed will be delivered to the manger 15. The stall 1 when closed by the gate 5 protects a cow feeding in the stall, allowing her to eat her rations without interference or pilfering from other cows. The arrangement of the apparatus is such that a cow cannot reach the manger without actuating the arm 18 and thus closing the gate 5. After a cow wearing the ferrous metal links has finished feeding, or if the cow does not have the links and therefore has no reason to remain in the stall 1, she backs out of the stall pushing her rump against the gate 5 and at the same time releasing the arm 18 so that the gate 5 is allowed to open under the action of the torsion spring 8 and the arm 18 is caused to return to a position blocking access to the manger 15. The amount of feed delivered in response to the signal from the sensing unit 16, which depends upon the time during which the vibrator unit 12 vibrates the tray 11, can be varied by adjusting the value of R1, which gives a range of from 5 to 50 seconds for the vibration time of the tray 11. When the vibrator unit 12 has finsihed vibrating the tray 11 in response to the signal from the sensing unit 16 it cannot be reactuated for a period of about 15 minutes set by the circuit IC2. This prevents a cow from immediately obtaining a further quantity of feed. This period can be adjusted by varying the value of R7. One or more further feeding apparatus may be installed within the same animal enclosure as the feeding apparatus described above, the one or more further apparatus being identical with that feeding apparatus except that the sensing unit of each apparatus is arranged to sense identification means other than ferrous metal articles. For example, a second feeding apparatus may be installed having a sensing unit arranged to sense brass articles on an animal, which can be in the form of a few links of a chain attached to a plastics chain as hereinbefore described. This enables the feeding time of the herd to be shortened but at the same time ensures that one cow cannot obtain feed from each apparatus but only from the one for which it carried the associated identification means. WHAT WE CLAIM IS:

1. Animal feeding apparatus which comprises means defining a stall for an animal a closure member movable between an open position in which an animal can enter the stall and a closed position in which an animal within the stall is enclosed, the arrangement being such that the closure member is urged towards the open position, the apparatus further comprising a manger in the stall and means arranged to be operated by the animal to close the closure member on entering the stall and moving towards the manger and to allow the closure member to open on moving away from the in anger.

Il. Animal feeding apparatus as claimed

in any one of claims 1 to 10, wherein the means arranged to be operated by the animal to close the closure member as the animal moves towards the manger and to allow it to open as the animal moves away from the manger comprises means which is movable between a position in which it projects into the path of movement of the animal to the manger and in which it allows the closure member to be in its open position, and a position out of the path of movement in which it causes the closure member to move to its closed position, the said means being movable from the former position to the latter position by pressure exerted by an animal on the said means as it moves towards the manger.

12. Animal feeding apparatus as claimed in claim 11. wherein the said means is urged towards the said former position and is arranged to be maintained in the said latter position by the body of the animal while it is in the manger.

13. Animal feeding apparatus as claimed in claim 11 or claim 12, wherein the said means is arranged to move between the said former and latter positions by rotation about a vertically-extending axis.

14. Animal feeding apparatus as claimed in any one of claims 11 to 13, wherein the said means is in the form of a pivotal arm.

15. Animal feeding apparatus as claimed in any one of claims 1 to 14, wherein the closure member is in the form of a gate.

16. Animal feeding apparatus as claimed in any one of claims 1 to 15, wherein the closure member is movable between its open and closed positions by rotation about a vertically-extending axis.

17. Animal feeding apparatus as claimed in any one of claims 11 to 14, wherein the closure member is mechanically linked to the said means.

18. Animal feeding apparatus as claimed in any one of claims 1 to 17, wherein the means for delivering feed to the manger comprises a hopper for a supply of feedstuff and means for conveying feed from the hopper to the manger.

19. Animal feeding apparatus as claimed in claim 17, wherein the conveying means is a vibratory conveyor.

20. Animal feeding apparatus as claimed in claim 19, wherein the arrangement is such that time during which the vibratory conveyor is operational to convey feed to the manger in response to the control signal is adjustable.

21. Animal feeding apparatus substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

22. A plurality of animal feeding apparatus constructed in accordance with claim 4, the sensing means of each apparatus being arranged to sense a different kind of identification means.

23. A set of two animal feeding apparatus constructed in accordance with claim 4, the sensing means of one apparatus being arranged to sense a ferrous metal article on an animal and the sensing means of the second apparatus being arranged to sense a non-ferrous metal article on an animal.