CA1084578A

CA1084578A - Immobilizing animals

Info

Publication number: CA1084578A
Application number: CA257,888A
Authority: CA
Inventors: Lancelot H. Lines
Original assignee: Senil Nominees Pty Ltd; Australian Merino Wool Harvesting Ltd
Current assignee: Senil Nominees Pty Ltd; Australian Merino Wool Harvesting Ltd
Priority date: 1975-07-29
Filing date: 1976-07-27
Publication date: 1980-08-26
Also published as: ES450263A1; JPS5216377A; DE2634031A1; GB1539556A; JPS5910218B2; NZ181591A

Abstract

ABSTRACT

An animal can be temporarily immobilized by passing a pulsed electric current of a potential of about 40 volts maximum through the animal's muscles to cause a state of tetany in the muscles while leaving the organs in a relaxed condition. The pulsed electric current is supplied through sharp-ended needle electrodes implanted subcutaneously and clipped to the hindquarters and forwardly thereof along the spine of the animal, the electrodes piercing the skin and the fatty tissue beneath thereby to contact the ionized fluids beneath the skin so that a low voltage can be used.

Description

108457~

This invention relates to a method of and means for handling animals, and in particular to the handling of ar.imals such as sheep, cattle and other animals for handling or vetPrinary purposes.
5. In animal husbandry there is often the requirement to restrain or immobilize an animal for veterinary purposes, or in the case of a sheep, to allow shearing to take place. Conventionally this has been by some mechanical means for holding and restraining the animal, 10. or in the shearing of sheep to manually restrain the animal by the shearer while the shearer himself carries out the shearing operation. With animals such as wild beasts, the animal is drugge~ and anaesthetised, but this ~ is a relatively slow process, for it takes time for the ; 15. drug to anaesthetise the animal, and also after the treatment the animal takes a degree of time in order to recover.
The present invention relates to an improved method and means of immobilizing and handling animals, and is concerned with an electrical method and apparatus for 20. carrying out this manner of handling animals.
BACKGROUND OF THE INVENTION
In the field of electro-treatment of animals and humans, there is disclosed in the United States Patent No. 535,905 dated March l9, 1895; "A Method of and Apparatus 25. for Obtaining Nerves", granted to Horton W.P. and Jones A.B.
Also U.S. Patent No. 2,866,461, granted December 31st, 1958 to R. Suzuki, for "Apparatus for Producing Electric Anaesthesia" relates to apparatus for the electro-anaesthesia .

2.

- :
- ~ . : :' . : ' ~`` 1084S78 where the patient is anaesthetised in the area of the operation to be performed. Also U.S Patent No.

3,083,463, dated 2nd April, 1963, to Brooks B. and Sylvane A.A., relates to "Dental Drilling and Apparatus 5. Therefore".
Also it is known that electro-anaesthesia on large animals can be carried out, such as discussed in the article by C.E. Short, D.V.M. in Journal of American Veterinary Medical Association, Volume 145, No. 11, 10. entitled "The ApplicaLion of Electro-Anaesthesia on Large Animals". This discusses the techniques of total anaesthesia by passing an electric current through or around the head of the animal and results in total relaxation of the animal.
15. SUMMARY OF THF INVENTION
By research it has been discovered that animals can be immobilized by using an electrical current flow of low voltage and small currents, and of a particular frequency to Eorm a pulse, with a relatively short pulse 20. width, with a relatively large duration between the pulses, thus causing the muscles to be in a rigid state, or state of tetany.
This has a definite advantage in ~he shearing of sheep, where the sheep can be rigidly immobilized in a 25. desired position of the limbs, this a~lowing a purely mechanical shearing of the sheep to take place~
Also with other animals, such as cattle, horses and even wild animals, the animals can be immobilized ''~ ' ' ;

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10845'78 , .

while in a standing position, to allow veterinary and animal husbandry work to be carried out.
According to one aspect of the present invention, there is provided a method of producing temporary immobiliza-tion of an animal undergoing animal husbandry without rendering the animal unconscious, including the step of after first - implanting electrodes subcutaneously and then clipping them to the hindquarters and forwardly thereof along the spine of the animal, the electrodes piercing the skin and the fatty tissue ;~;
beneath thereby to contact the ionized fluids beneath the skin allowing a low voltage to be used, subjecting the electrodes to a current flow of a potential of about 40 volts maximum to produce immobilizing simultaneous muscular tetanic contraction in the animal.
According to a further aspect of the present invention, there is provided apparatus for immobilizing j animals, the apparatus being characterised by an electric ! power source, electrodes connected to the power source, said electrodes beiny characterised by (1) needles with sharp ends to be implanted subcutaneously in the animal in combination with (2) spring--biased clips for clamping to the hide of the animal to retain the needles.
BRIEF DESCRIPTION OF THE DRAWINGS
. FIG. 1 is a diagrammatic illustration of the immobilizer, FIG. 2 is a circuit diagram of the immobilizer, and FIG. 3 is a chart of the currents required for various weights of cattle.
DESCRIPTION OF THE PREFERRED EMBODIMENT
It has been determined that the immobilization of animals can be carried out by an electric current, having a potential of 40 v. and a current in the vicinity of 50 milli-amperes will immobilize a sheep, and that about 100 milliam-B ~ 4 _ . ~

peres is required for immobilizing cattle, the current being pulses of 50 Hertz, each pulse being of 1 millisecond and spaced 20 milliseconds apart.
Research work to date has shown that a current having a constant amplitude driven by a low voltage high impedance source is safer for operators to use, and this can be achieved if the electrodes which are attached to the animal are so designed that they pierce the skin at the point of application, so as to make contact with the ionized fluids under the skin and/or in the muscular tissue of the animal.
Indeed the work has shown that it is the magnitude of the current for a particular wave characteristic, frequency and points of application that determines the immobilizing effect, rather than the voltage required to - 4a ---- 10t~9~5'78 ';~
drive this current.
The skin of most animals is comprised of horny (dry cell) outer layers beneath which is found a layer of fatty tissue, and under this fatty tissue layer exist the ionized body fluids and muscular tissue.
The electrical resistivity of the horny outer layers in the adjacent fatty tissues is high, relative to the electrical resistivity of the ionized body fluids and muscular tissue.
If electrodes were simply placed or clipped on the outer skin, most of the voltage would be consumed in driving the required current through the horny outer layers and adjacent fatty tissues, while only a small part of this voltage would be consumed in driving the required current through the ionized body fluids and muscular tissue within the animal.
On the other hand, if the electrodes pierce the skin first and make contact with the ionized body fluids and muscular tissue, relatively low voltages, safe for the human operators to handle, would be required to drive the immobilizing currents through the animals.
It was also found that the resistance between the electrodes to some extent, depended upon the area of contact that the electrodes made with the ionized body fluids and muscular tissue, so that as this area increased the resistance between the electrodes decreased.
In particular application on cattle and sheep using a pulsed current source of 50 Hertz frequency, .. . .

and a pulse width of 1 millisecond whose amplitudes could be controlled accurately between 0 and 1 amp.
and whose voltage did not exceed 40 volts, the largest animals were easily immobilized without detrimental effect to the animals or electrical hazard to the human operators on application of the electrodes.
In a particular design of the electrodes, a spring-actuated plunger incorporated in an insulating housing and operated by a trigger mechanism which can be reset, contains on one end of the plunger either barbed, straight or current needles, depending on the requirement, connected to a conducting strip or rod which makes contact with the current source on operation of the plunger. The barbed or curved needles ensure that the electrodes remain attached to the animals even though they may make a violent movement on insertion of the electrodes.
It is not intended that the electrodes be limited to the above design, but they may have various shapes or sizes and be applied in any manner provided that they preferably contact the ionized body fluids and/or muscular tissue under the skin of the animals.
The invention is designed to immobilize cattle and other animals in a quick, safe manner so that operations such as shearing, dehorning, castration, etc., and other forms of surgery may be carried out in the field or elsewhere in an efficient manner, with the minimum of physical effort required to restrain the animal. The ~ 108457B

animal is immobilized by the passage of the small electric current through the nerve and the muscle tissue thus causing tetany, that is the contraction of the muscles, thus immobilizing the animal and effecting its nervous system in such a way that the animal is not conscious of any pain when the correct current is applied.
No ill effects have been observed to date on the many experiments carried out on animals, but care must be taken to ensure that the current applied is not so great that it prevents the animal breathing for a period long enough to produce asphyxia. It is felt that the immobilization can have a therapeutic value on the animals.
The electronic unit is equipped with a warning device which makes a buzzing sound when the electrodes are not connected, or when the electrodes are making a poor connection on the animal. This is considered necessary as the animal will recover from its immobilized state within a few seconds of removing the required immobilizing current.
Turning now to FIG. 1, this shows the electronic unit 1 having an outward lead 2 connected by a plug 3 to a pair of electrode leads 4. Each lead 4 is connected in this example, to two electrodes, a dart electrode 5 and a clip electrode 6. For large animals such as cattle, the dart 5 is used first to immobilize the animal, and then the clip electrode 5 can be inserted in the desired location.
For the immobilization of sheep, it is not required 108~78 to use the dart electrodes, but the clip electrodes can be applied directly to the sheep.
FIG. 2 shows a schematic circuit of the immobilizer, where the output current Io is equal to Ein divided by the reference resistance (R reference). The error amplifier and the series transistor T maintain the outward current Io at a level such that the voltage drop across the reference resistance (R reference) is equal to Ein. The voltage from the reference voltage supply is passed to an adjustable potentiometer P, which provides adjustment of E in such a way that Io can be adjusted from O up to ; 0.3 amperes. To pulse the outward current the series transistor T is turned on and off by an oscillator and transistor switch.
The oscillator is adjusted to such that the output pulse width is 1 millisecond and the pulses occur at 50 Hertz, and the output current is continuously adjustable with a resolution of better than 1 milliamp. The voltage compliance of the output is 40 volts, and this can be readily changed.
FIG. 3 shows a chart of tests which have been carried out on cattle, plotting animal weight against peak current applied to the animals. Experiments have shown that while it is initially assumed that a variation in current required would correlate to the animal weight, that this is not so, for it is shown in the graph that the general level of immobilization is between 80 and 300 milVamperes. Smaller animals often require greater ' ~, :i084S78 current flow than larger animals, but generally it has been noticed that younger animals require an increased current flow for immobilization.
While no direct correlation is yet available, it may well be that there is a correlation between the vitality or energy of the animal and current flow.
It has been found that with certain breeds of cattle, for example BOS TAURUS which is essentially an English breed, that current values as shown in FIG. 3 are obtained. However with other breeds such as the tropical breed BOS INDICUS, that higher currents up to 300 milliamperes are required to immobilize the animals.
For the immobilization of cattle, the initial setting, it is estimated, should be 100 milliamperes, and the cllrrent then increased or decreased accordino to the state of immobility induced in the particular animal. The initial effect is for the animal to stiffen up to such an extent that breathing is temporarily arrested. Between 1 arld 2 minutes however, the animal commences to breath again, which is indicated by the heaving of the chest wall and flanks.
If signs of breathing are not evi~3ent after this time, the current setting should be reduced quickly to allow the animal to breathe, but not so far as to entirely reduce the stiff condition of the animal.
Animals have been kept immobilized up to twenty minutes in experiments performed so far, without any apparent ill effects. It will be noticed however, that ', ~

lV84S78 after several minutes an animal tends to accommodate itself to the current levels being used, and a further one or two fine increments of the current may be necessary to maintain the immobile state.
Where dehorning, castration or some other operation : is to be performed on the animal, it is preferable to Y apply a heavier current than the threshold level for immobility, and to perform the operation without waste of time, rather than applying a current just over the threshold level and having to increase the current to maintain their immobility.
The animals recover immediately, and sheep have begun grazing within minutes of being removed from the immobilizing current, and all animals show no signs of distress after the immobilization.
While the invention is particularly adapted for completely immobilizing an animal by applying the current from head to tail of the animal, the animal may be positioned as desired, and by slightly reducing the current, repositioning the animal in the desired position, and then raising the current to cause the animal to again stiffen. The animal can be held in any position.
Also various portions can be held as desired so that by applying the current to portions of the body such as a leg, the leg muscles can then be held in any desired position. For example, by applying the current to a rear leg of a horse, that leg is immediately held up by the passage of the current through the muscles, the leg being 10.

108gS78 held in a position whereby shoeing or other treatment can be carried out on that leg or hoof. Thus by applying the electrodes to the desired muscles, the leg can be held as positioned.
Thus it has been found that various parts of the animal may be in a state of tetany while other parts may be relaxed. Thus it is possible to stiffen the major muscles, while the organs are relaxed, for example, the internal organs, testes and mammary glands.
Cows while being immobilized have been milked substantiating the fact that various organs can be relaxed.
It has also been found on investigation, that while the optimum current to be applied is a pulse of a short time interval such as 1 millisecond with a large period, say 20 milliseconds, between each pulse, it has been found that restraint and immobilization can be obtained by the application of pulses and wave forms other than those described.
Thus it has been found that by the application of an alternating current of even sinusoidal wave form is satisfactory to restrain an immobilized animal.
Also other wave forms such as a square wave, a triangular wave, and the application of both unipolar and bi-polar forms can be utilized to restrain the animal. Thus it is to be realised that the invention is not limited to the specific pulse formation as described as being the optimum form, where it has been found that other - 1084~78 "
. .
. wave forms can produce satisfactory results without ~; detrimental affects to the animal.
In this respect also it has been found that a pulse or alternative wave form is not essential but - 5 that restraint can be applied by the application of a ; direct current to the animal, although it has been found that the pulsating form is preferred.
In a further application of the invention micro switches may be included in the line of the clip, so that this forms an additional safety feature. Thus it is possible now to apply the clips without any electrical supply being provided to the clips themselves, and the controls can be adjusted to give a minimum voltage of the like, so that on switching on the micro switches at the clips, the animal can be immediately restrained, and then the control can be adjusted to give the required degree of immobilization.
This is of advantage, for otherwise the animal can sometimes be affected by a small electrical current flow which would be annoying or aggravating to the animal, which may struggle before the control is adjusted to achieve the desired degree of immobilization, and hence, with the use of the micro switches the animal can be j immediately and instantaneously immobilized or restrained without feeling any affects or build-up to this - immobilizing degree.
The invention is of particular importance also for immobilizing sheep to allow fully automated shearing ; operations to take place.
Thus the immobilizing current may itself, be utilized in assisting the positioning of a cutter by sensing means. For example, this current through the animal produces a field which can be sensed by a sensing coil, and also an additional high frequency can be super-imposed on the immobilizing current, and this high frequency field can be sensed.
Furthermore a tuned coil can be used to sense the proximity of the contour, the tuned coil being insulated, so that the proximity of asurface causes the coil to be detuned.
Also other proximity sensors can be used, such as capacitance sensing, force, sensing or even force sensing.
Thus the invention can be applied to the immobilization of animals in general, and while it is particularly adapted to the use of animals of a domestic or agricultural nature, it is to be readily seen that the invention is also applicable to beasts and animals of any kind, and for example, by utilising a device with a portable power source, and some form of portable race or crush that animals in the field or even in the wild state can be driven into such a race or crush and then immobilized for treatment, shearing or any other desired purpose.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method of producing temporary immobilization of an animal undergoing animal husbandry without rendering the animal unconscious, including the step of after first implanting electrodes subcutaneously and then clipping them to the hindquarters and forwardly thereof along the spine of the animal, the electrodes piercing the skin and the fatty tissue beneath thereby to contact the ionized fluids beneath the skin allowing a low voltage to be used, subjecting the electrodes to a current flow of a potential of about 40 volts maximum to produce immobilizing simultaneous muscular tetanic contraction in the animal.

2. The method of claim 1 including the additional step of clipping another electrode to the mouth of the animal, said other electrode being connected in parallel to one of the first-named electrodes.

3. A method of immobilizing animals as defined in claim 1 characterised in that the current is comprised of spaced pulses, the duration of each pulse being small in relation to the spacing between the pulses.

4. A method of immobilizing animals as defined in claim 3, characterised in that the frequency of the pulses is 50 Hertz.

5. A method of immobilizing animals as defined in claim 4, characterised in that each pulse is about 1 milli-second in duration.

14.

6. A method of immobilizing sheep as defined in claim 1, characterised by applying a current flow of 40 to 60 milliamperes.

7. A method of immobilizing cattle as defined in claim 1, characterised by applying a current flow of 80 to 300 milliamperes.

8. Apparatus for immobilizing animals, the apparatus being characterised by an electric power source, electrodes connected to the power source, said electrodes being characterised by (1) needles with sharp ends to be implanted subcutaneously in the animal in combination with (2) spring-biased clips for clamping to the hide of the animal to retain the needles.

9. Apparatus according to claim 8 characterised by means for oscillating the power voltage at a rate of about 50 Hertz and including switches which contact for about 1 millisecond.

10. Apparatus according to claim 8 or 9 in which the current flow is limited to a potential of about 40 volts and in which the current flow is in the range of 40 to 300 milliamperes.

15.