GB2058359A - Activity measurement apparatus for animals - Google Patents

Abstract

A system for detecting estrus in cows comprising an apparatus for detecting their rate of motor activity (movement). A transmitter 3 individual to a cow sends a very short burst of energy to a receiver, at a rate depending on the movement rate of the cow, which counts or records the bursts graphically. The bursts are such as to conserve battery power, minimizing servicing thereof, a burst of a predetermined period and of a frequency individual to the cow being transmitted via an aerial 4 each time a mercury switch attached to the transmitter is closed. Count rate of as much as 50% increase indicates reliably the presence of estrus, and a count rate significantly lower than normal can indicate illness. <IMAGE>

Description

SPECIFICATION Activity measurement apparatus for animals This invention relates to an apparatus for measuring the motor activity (movement) of animals, and particularly of dairy cows as an indicator of the presence of estrus.

To maximize calf production of cows, it is usually desirable to impregnate each cow of a typical herd at about 80 dayssfollowing calving. To delay later than 80 days reduces the production of the herd. It has been estimated that the economic loss to the producer for each day that conception is delayed beyond 80 days after calving is between $1.00 and $1.60 per cow. Clearly, where hundreds of thousands of cows are in production within a given geographic area, the economic advantages could be substantial with improved ability to pinpoint the specific time of estrus of each cow, whereupon artificial insemination can be utilized.

The period of estrus in cows is normally about seven to ten hours, and due to the short period of estrus, it has been difficult to discern accurately the period of estrus on a reliable ongoing basis.

Consequently as many as 120 days typically elapse between calving intervals.

Methods used at present to detect estrus are by direct observation (for example, observation of frequency of mounting), the detection of temperature change with temperature-sensitive chemicals or the like, or observation by means of closed circuit television. All of these methods require the attendance and observation of an attendent, and placement of mechanical devices adjacent or in contact with the cows.

It has been discovered that the motor activity of cows increases significantly during the period of estrus. The present invention makes use of this discovery to provide an automatic indication of when a particular cow is in estrus.

A loop of rope is placed around the head of a cow, and a switch which is sensitive to movement, such as a mercury switch attached to the rope, closes randomly with movement of the cow. Each time the switch is closed, a transmitter operates and the transmitted energy is received at a receiver for recognition.

The use of a movement sensor to determine movement of an animal is not new in itself. For instance, in U.S. Patent 3,336,530, a portable radio transmitter is carried by a hunting dog, and a pair of tones which are sent out by the transmitter are received by the hunter carrying a receiver. The frequency of change of tones is heard by the hunter, and when the changes stop, and a single tone is heard, the hunter knows that the dog is "on-point". Further, the receiver can be used to home-in on the transmitter, and thus allow the hunter to discover his prey.

In this and other motion sensing systems, there is a particular drawback which forbids its use in a system such as the present invention. The transmitter can only be used for a short period of time since it is constantly on, or is used for a significant long duty cycle, thus draining the battery after a short period of time. Where the system is to be used for days or weeks at a time in the field, the prior art system is clearly unfeasible.

In addition, the prior art system does not provide for an automatic determination of movement rates. The user must depend on decoding and interpretation of the information by himself.

On the other hand, the present invention provides for substantial battery conservation, which allows use of the transmitter in the field for many weeks without the requirement for servicing of the battery. The invention automatically provides a numerical or other display related to movement, giving an indication of the movement rate of a cow, which when compared with the cow's normal rate of movement, provides an indication of estrus beyond a shadow of a doubt.

In addition, it has been found by the use of this invention that a slowed rate of movement of a particular cow relative to its normal rate can indicate the presence of disease. The producer can thus provide prompt attention to the cow, possibly avoiding contamination of other cows in the herd.

Clearly the use of the present invention affords substantial improvement of herd management, including increasing efficiency of production and reduction of costs.

It should be noted that the invention is not restricted to cows, but can be used to detect rates of movement of other animals for the same or other reasons, particularly to domesticated animals.

The invention in general is a system for determining the rate of movement of an animal comprising a transmitter for attachment to the animal, a keying circuit for causing the transmitter to transmit short bursts of energy with movement of the animal, a receiver for receiving the bursts of energy, and means for counting the received bursts of energy, whereby the rate of movement of the animal can be determined.

More specifically, the system is comprised of a transmitter for attachment to the animal, and a keying circuit for causing the transmitter to transmit short bursts of energy with movement of the animal, in which each of the short bursts of energy is emitted for a predetermined period of time. Preferably the keying circuit is initiated by operation of a switch, the periods of the short bursts of energy emissions being made unrelated to the time the switch is closed, but related to the preferred time of emission. Since only extremely short bursts of energy are emitted each time a switch is closed, with large periods of time in the gap between bursts, conservation of battery power is achieved sufficient to allow the transmitter to operate in the field for weeks.

Since a plurality of transmitters on different cows are intended to be used in an operating system during the same time, the emission frequencies of the various transmitters should be different. The receiver should thus have different frequency channels with counters associated with each channel. Preferably the receiver is of the scanning type, in a prototype, the receiver scanned each channel once each second. While bursts occurring during the time that the channel is not being scanned are not counted, the total number of bursts counted relative to the total number of bursts counted during periods of nonestrus can be determined, and has been found to be a reliable indicator of estrus and other relevant factors.

Further, it should be noted that the counter can be of an electronic type, which adds a voltage increment to a sum each time a burst is to be counted, or adds the bursts digitally. The apparatus should reset after predetermined periods of time. An overcount or overvoltage detector which operates an alarm can thus provide an indication if the number of bursts counted during a given interval is in excess of a predetermined minimum. This gives the producer an indication that the cow is in estrus.

Of course, the count threshold can be made variable, and can be established for each particular cow (that is, for each channel), after experience as to the normal count rate for each cow. The system can thus automatically provide the producer with an indication that a cow is in estrus, without attendance except to the alarm. He can read the various counts for various channels, and know unerringly which cow is in estrus, and immediately perform the artificial insemination.

A better understanding of the invention will be obtained by reference to the detailed description of the invention below, and to the following drawings, in which: Figure 1 is a view of the transmitter as it is to be applied to an animal, Figure 2 is a schematic diagram of the transmitter, Figure 3 is a block diagram of a receiver, and Figure 4 is a schematic diagram of a modification to a receiver.

For ease of description, cows will be the animals referred to below, although the invention can be used with a variety of animals.

Turning first to Figure 1, a rope 1 is provided with a loop and clip 2 at its ends for secure joining together, whereby the rope can be looped securely around the neck of a cow.

A housing 3 is hung on the rope by any well known means. In a successful prototype, the rope was looped through a pair of holes in the housing.

Within the housing the transmitter is fastened. An antenna 4 for the transmitter can be looped through or around the rope 1.

Preferably the housing is relatively heavy, in order that it might pull the rope around the neck of the cow so as to hang below, whereby it will be maintained in an approximate constant position, and not ride up the side of the neck of the cow. In this respect the rope 1 should be loosely hung around the neck of the cow.

Within the housing 3 a movement sensitive switch is located for keying the transmitter.

Preferably the switch is a well known mercury operated switch. In this switch an amount of mercuty is disposed within a glass tube in which a pair of contacts is located. When the mercury runs to the side of the tube where the contacts are located, the mercury completes a conductive path, closing an externally connected circuit.

It may be seen that with movement of the cow, the mercury switch repeatedly and randomly will close. The period of the switch being closed will also be sporadic. However the frequency of closure will be found to be related to the movement rate of the animal.

The transmitter is preferred to be keyed only upon the switch becoming closed. in other words when the switch is closed for a long period of time, or with the switch being open circuited, the transmitter should not operate.

Figure 2 shows the preferred form of the transmitter. A transmitting circuit 5 of well known form is shown, which includes oscillator transistor 6 and output transistor 7. The output transistor preferably is biased into class C mode of operation, but can be biased with the base of the output transistor connected through a resistor to its emitter. In these cases, and with no D.C.

connection from the base to the + pole of the circuit battery and with the absence of an input signal, it is biased into quiescence, and does not draw operating current.

The oscillator transistor has its base connected via resistor 8 to the negative power supply terminal, and as such is biased into quiescence. In its idle state, therefore, neither transistor 6 or 7 draws operating current. Of course while NPN transistors are shown, PNP transistors could be used with an opposite polarity power supply.

The base input of transistor 6 is connected through resistor 9 in series with capacitor 10 and mercury switch 11 to the positive terminal of a battery 12. The battery negative terminal is connected to the aforenoted resistor 8. Further, its positive terminal is connected to the positive supply lead (unreferenced) of the transmitting circuit 5. Capacitor 10 is bypassed by resistor 13.

In operation, movement of the cow will close mercury switch 1 1 temporarily. Capacitor 10 thus charges during the closure period, for a period of time dependent on the RC time constant of its capacitance with the resistance of resistor 9. The charging current flows into the base of transistor 6, thus providing bias current for operation. The transistor will oscillate in a well known manner, applying a signal to class C amplifier transistor 7.

The signal is amplified and passes to the external antenna 4, whereby radio frequency electromagnetic energy is emitted.

Once the capacitor has become charged or nearly charged, the current flow into the base of transistor 6 becomes insufficient to sustain oscillation, and the resulting emission of radio frequency energy stops. This will occur notwithstanding that mercury switch 11 remains closed.

It should be noted that resistor 13 should be of large value which provides a current discharge path around capacitor 10, conducting a current level which is insufficient to maintain oscillation of transistor 6.

With switch 11 remaining closed, or opening again, capacitor 10 begins slowly discharging through resistor 13. Once it has discharged, either fully or partly, an additional closure of mercury switch 11 will cause capacitor charging current to flow as described above.

The energy emission time is a significant portion of the charging period of capacitor 10, but this period is small in comparison to the total elapsed time. In a successful embodiment of the invention, capacitor 10 was 5 microfarads and resistor 9 was 15,000 ohms. Resistor 13 was 220,000 ohms. This allowed use of a 9 volt battery as battery 12, to power the transmitter.

Transmitting circuit 5 can be of various well known forms, rather than the specific circuit form shown. It is desired, however, that the circuit should be quiescent except when keyed by the circuit including mercury switch 1 1, capacitor 10 and resistor 9, in order to minimize the use of battery current. The keying circuit in Figure 2, of course, not only causes operation of the transmitter, but also establishes the time period of operation thereof.

The operation frequency of the transmitter of the noted prototype was 150MHz, unmodulated.

It has been found that modulation is not required.

Where various transmitters were used for a herd of cows, the frequencies were preferred to be about 90kHz apart.

Where a plurality of transmitters are used for monitoring the motor activity of a herd, a number of different types of receivers could be used.

Individual receiver channels each tuned to a frequency of a corresponding transmitter can be utilized. The receiver channel can incorporate circuitry for rectifying the burst of radio frequency energy which is received at its frequency, converting it to a pulse, and applying the pulse to a counter. As noted earlier, the counter can be set with an automatic reset at intervals of, for example, 3 hours, and a count in excess of a normal count at the reset time can be connected to an alarm. This form of circuit is each receiver channel will provide the desired result.

However, it is preferred that a scanning type of receiver should be used. The receiver used in a prototype was the VHF SCANNING MONITOR model GR1 10, available as Heathkit, from the Heath Company, Benton Harbour, Michigan, U.S.A. Modifications of this receiver allow it to be used in the present invention.

Turning to Figure 3 a general block diagram of the preferred scanning monitor is shown. An antenna 1 5 is connected to the input of an radio frequency amplifier and mixer circuit 16. The output of the mixer is applied to a filter and intermediate frequency (IF) amplifier, which is connected to a detector and squelch, the latter assemblage being shown generally as block 17.

The output of the detector is connected to an audio amplifier 18 which has a speaker 19 connected thereto. Amplifier 18 and speaker 19 are not required as part of this invention, but can be used if desired.

Alternatively a low power amplifier and a light emitting diode can be used at the output of the squelch, whereby the diode indicates whether the output is at +5 volts or zero. The squelch control is turned so that the light operates or turns off upon the reception of a signal.

The output of the squelch is connected to a digital scanning and priority circuit 20, (which is disabled so that scanning continues at a regular speed whether or not signal have been received), the output of which is connected to an eight channel oscillator 21. The output of oscillator 21 is connected to amplifier 22, which has its output connected to the mixer of RF amplifier and mixer 1 6, in order to establish the frequency to be amplified by the IF amplifier.

The circuit also includes a display 23 which shows which of the channels is being scanned at a particular instant.

The operation of this circuit is well described on pages 75 and 76 of the Heathkit Assembly Manual, available from the aforenoted Heath Company, and therefore its recitation would be redundant. However a brief description of the portions important for an understanding of the present invention will be made.

In digital scanning portion of the circuit, a counter 24, referenced as IC 101 in the aforenoted Manual is operated from a scan oscillator circuit, and receives impulses at the rate of approximately 1 per second from the scan oscillator. In a prototype, counter 24 was changed to count from 0 to 5 (a count of 6), rather than from 0 to 7 as in the available scanning monitor to reduce the number of channels. However, if the RF spectrum space is available, it can be retained to count from 0 to 7.

In order to modify it to count from 0 to 5, counter 24 is connected directly to counter 25, which is described in the noted Manual as IC 105.

The circuits IC 102, IC 103 and IC 104 in the kit are deleted.

The output terminals of counter 25 go to low potential level or ground with counting for 1 second, in sequence.

Crystals 26A-26F are referenced in the aforenoted Manual as Y1 00-Y1 05. It is preferred that the switches S101A-S105 connecting the crystals to the outputs of IC 105 should be bridged or short circuited, or otherwise permanently closed and are therefore shown as directly connected thereto. The inductors 27A-27F, capacitor 28A-28F and resistors 29A-29F are respectively series connected between crystals 26A-26F and the output terminals of counter 25.The inductors correspond to inductors L110--L115, the capacitors 28A-28F correspond to capacitors C151--C155 and resistors 29A-29F correspond to resistors R141, R143, R145, R147, R149 and R152 in the noted Monitor. Diodes 30A-30F are connected between the junction of capacitors 28A-28F and resistors 29A-29F respectively, and correspond to diodes D101-D106 of the circuit in the Heathkit Monitor. Numerous components which are present in the monitor have not been shown in the present schematic, since their presence would only add needless complexity to the present description.

Returning now to the description of operation, the output terminals of counter 25 each go to low level or ground for one second in sequence. This in turn switches individual corresponding crystals into the oscillator circuit of the scanning monitor.

In this manner, individual local oscillator frequencies are generated, which are fed to the mixer as noted earlier, to establish the frequency of reception.

In the aforenoted scanning monitor, the IF amplifier contains a noise amplifier, which is normally used to activate the squelch. The presence of noise indicates that no signal is being received. The noise is converted into a +5VDC positive voltage. If a signal is received, there will be no noise and this positive voltage falls to zero.

The +5VDC or zero volt squelch output signal is provided at the output of transistor Q205 in the aforenoted assembly manual. This is applied to lead 31, labelled herein "from squelch".

In the present invention each of the output leads of counter 25 is connected through a corresponding resistor 32A-32F to the input of a counter operate circuit such as 33F, Only one representative counter circuit is shown, although one is connected to each of the resistors 32A-32F.

The squelch lead 31 is connected via resistors 34A-34F to corresponding leads which are input to the individual counter operate circuits 33A-33F.

Each of the counter operate circuits in sequence thus receives a signal which is output from counter 25, each one as well as a signal from the squelch on lead 31. If both the squelch and one of the signals output from counter 25 go to low level at the same time, the counter circuit connected to the corresponding counter output lead is activated.

Assuming that a particular output lead from counter 25 is activated (goes to low level), the corresponding crystal will be caused to oscillate, generating a signal in the oscillator (in the present case at its third overtone) which is applied to the mixer, resulting in a particular received frequency to be amplified in the intermediate frequency amplifier. Should a signal be received, the voltage level on the squelch lead 31 will go to low level at the same time as the counter output lead, causing operation of the counter operate circuit which is connected to the particular output lead of counter 25 which has gone to low level. An event counter or display connected to the counter operate circuit thus registers a count.

On the other hand should only noise be present at the frequency being monitored, the squelch lead 31 will be at high level and the corresponding counter operate circuit will not be operated.

In the counter operate circuit 33F which is shown, the input lead is connected to the base of a transistor 35, which, being of NPN type, has its emitter connected to ground.

The collector of transistor 35 is connected to the base of a second NPN transistor 36, which also has its emitter connected to ground. A biasing resistor 37 connects to collector of transistor 35 and the base of transistor 36 to a source of potential+V#.

The collector of transistor 36 is connected to the coil 38 of an electromechanical counter, to the terminals of which a reverse EMF protection diode 42 is connected. The coil 38 is also connected to source of potential +Va.

Should it be desired also to operate a pen or other type of recorder, an additional transistor 39 can be connected as transistor 36, with its base to the base of transistor 36, and its emitter connected to ground. Its collector is connected through transducer coil 40 to the recorder. The other terminal of the coil 40 is connected to a source of pOtential+V#, and a reverse EMF protection diode 41 is connected across the coil.

Upon receipt of a low level or ground signal at the base of transistor 35, which can only occur with the simultaneous reception of a low level signal on the squelch lead 31 and an output of counter 25, transistor 35 is caused to conduct, which in turn causes transistor 36 to conduct. With operation of transistor 36, a circuit is provided from potential source +Va, through coil 38 and the collector emitter circuit of transistor 36 to ground.

This causes registration of an additional count on the counter comprising coil 38.

With the connection of transistor 39 as shown, transistor 39 will operate with transistor 36, causing operation of coil 40 and registration on the corresponding event recorder.

In place of resistors 32A-32F and 34A-34F, two input AND gates can be used.

In place of each of counter operate circuits 33A-33F, the clock input of an integrated circuit counter can be used, whereupon the individual counters are caused to count sequentially with the reception of coincident low level pulses on lead 31 with the output leads of counter 25. A long time counter which provides a low level or ground pulse to the reset input of the latter counters provides for resetting of the counter at predetermined intervals. An alarm driver circuit should be connected to a particular count output of each of the latter counters, in order than an alarm should be operated when the number of counts exceeds a predetermined number prior to the timed resetting.

Rather than using counters, a graphical recorder can be used in place thereof or in addition thereto, with pens recording the individual rate of movement of the cows, one per recoder channel.

This provides the advantage of a permanent record, of 24 hours per day.

It may be seen that with the resetting function described, under ordinary circumstances the count would never reach the predetermined alarm count level. However during the period of estrus of the cow, with the emission of a greater frequency of pulses from the transmitter, the count, prior to.

reset, would reach the output level which operates the alarm. Hearing of the alarm, allows the producer to initiate artificial insemination of the cow related to the corresponding channel which set off the alarm. Clearly this allows maximum utilization of herd fertility, with substantially increased reliability.

It has been determined that the presence of estrus results in an increased count rate of 50% over normal, although it will normally increase during feeding and decrease during sleep. Ths count has been found to decrease significantly from a particular cow's normal rate if it is sick.

It should be noted that with the preferred scanning circuit which is described, only 1/6 of the energy bursts or pulses emitted by a transmitter on a particular channel are recorded, since the scanner receives a particular channel only 1 second ount of 6. However this count has been found to be a reliable sample of the amount of motor activity.

It should also be noted that a plurality of receivers and a plurality of transmitters corresponding thereto can be used, for larger herds. In addition, the audio amplifier and speaker can be utilized to provide an audible indication of the motor activity of the herd, a light emitting diode array can also be utilized.

It should be understood that the preferred embodiment described above is only illustrative of the principles of the invention. Other embodiments, and modifications of the present circuit may be utilized within the sphere and scope of the invention. All are deemed to be within the present invention as defined in the claims appended hereto.

Claims (19)

1. A system for determining the rate of movement of an animal comprising: (a) a transmitter for attachment to said animal, (b) keying means for causing the transmitter to transmit short bursts of energy with movement of said animal, (c) means for receiving said bursts of energy, and (d) means for counting said received bursts of energy, whereby the rate of movement of said animal can be determined.

2. A system as defined in claim 1, in which each of the short bursts of energy is emitted for a predetermined period of time.

3. A system as defined in claim 1, in which the keying means is comprised of switch means randomly operated upon movement of said animal for applying operation current to the transmitter, and means for controlling the time of each burst of energy irrespective'of the time that the switch means is closed.

4. A system as defined in claim 1, in which the transmitter is comprised of a radio frequency oscillator having an input for receiving bias current, a capacitor in series with a switch connected between said input and a current source, and resistor means connected in a discharge path to the capacitor, the switch being randomly operated upon movement of said animal, whereby charging current for said capacitor is applied for a period of time dependent on the capacitance of the capacitor to said input upon closure of the switch, the oscillator thereby being caused to operate during the interval of a significant portion of charging current flow.

5. A system as defined in claim 4, further including a second resistor connected in series with said capacitor for partly controlling charging time of the capacitor, and a transmitter connected to the output of the oscillator, adapted to be quiescent in the absence of oscillation of the oscillator and to transmit a radio frequency signal during oscillation of said oscillator.

6. A system as defined in claim 1, in which the keying means is comprised of switch means randomly closed for indefinite periods of time upon movement of said animal, and means for causing the transmitter to emit a burst of radio frequency energy for a predetermined period of time upon closure of the switch means.

7. A system for determining the rate of movement of an animal comprising: (a) a transmitter for attachment to said animal, (b) keying means for causing the transmitter to transmit short bursts of energy with movement of said animal, in which each of the short bursts of energy is emitted for a predetermined period of time.

8. A system as defined in claim 7, in which the keying means includes a switch adapted to be randomly closed for indefinite periods with movement of the animal, the switch being connected in a circuit to said transmitter to cause said transmitter to operate, and further including means for causing a burst of radio frequency energy to be emitted each time the switch is closed for a predetermined period which is equal to or shorter than the time period that the switch is closed.

9. A system as defined in claim 8, in which the transmitter includes an oscillator transistor having a bias current input, the output of the oscillator transistor being connected to the input of an output transistor circuit which is biased for class C operation, the oscillator transistor circuit being adapted to be in its quiescent state in the absence of said bias current, a source of current, a capacitor in series with a first resistor connecting the current source to said bias current input,.and a second resistor connected in a circuit around the capacitor for discharging the capacitor, the time constant of the capacitor and the first resistor being selected to establish said predetermined period.

10. A system as defined in claim 3, 8 or 9 in which the switch is a mercury switch.

11. A system as defined in claim 3, 8 or 9 in which the switch is fixed to a loop of rope for disposition around the neck of an animal, and a weight attached to said rope having below the neck of the animal and orienting the switch physically in a predetermined position to facilitate random operation with movement of the animal.

12. A system as defined in claim 3, 8 or 9 in which the switch is fixed to a loop of rope for disposition around the neck of an animal, and a weight attached to said rope for hanging below the neck of the animal and orienting the switch physically in a predetermined position to facilitate random operation with movement of the animal, the weight comprising a housing enclosing said transmitter and keying means.

13. A system as defined in claim 1, in which the means for counting includes a circuit tuned to the frequency of the received energy, and for detecting and recording said received burst of energy.

14. A system as defined in claim 1,4 or 6 in which the means for counting includes a circuit tuned to the frequency of the received energy, means for converting each received energy burst into a signal pulse, and counter means for counting the pulses.

15. A system as defined in claim 1, further including a plurality of transmitters tuned to different frequencies for attachment to individual animals, keying means connected to each of the transmitters for causing each of the transmitters to transmit short bursts of energy with movement of said animals, in which the means for counting includes a plurality of circuits each tuned to different frequencies of energy received from corresponding ones of the transmitters, means for converting bursts of energy received from each of said plurality of circuits into pulses, and counting means connected to said converting means for receiving and counting said pulses, each respective counter counting the pulses related to an individual frequency of a corresponding transmitter.

16. A system as defined in claim 1, in which the means for receiving said energy is comprised of a frequency scanner for scanning a plurality of different frequency channels associated with corresponding ones of a plurality of said transmitters, each transmitter having a keying means, the means for counting being comprised of means for converting the bursts of energy received in each channel to pulses, and counting means for counting the number of pulses received in each channel during the period the associated channel is scanned.

1 7. A method of determining the presence of estrus in cows comprising: (a) transmitting a plurality of bursts of energy, the frequency of the bursts being related to the movement rate of the cow, (b) counting a sample of said bursts within a predetermined period, and (c) comparing the total number of the sample with a predetermined number, and establishing the presence of estrus in the event the total number is greater than said predetermined number.

18. A method of determining the presence of sickness in cows comprising: (a) transmitting a plurality of bursts of energy, the frequency of the bursts being related to the movement rate of the cow, (b) counting a sample of said bursts within a predetermined period, and (c) comparing the total number of the sample with a predetermined number, and establishing the presence of sickness in the event the total number is smaller than said predetermined number over a predetermined period of time.

19. A system as claimed in claim 1, substantially as described herein with reference to Figure 1-3 or Figures 1 4 of the accompanying drawings.