WO2020040650A1

WO2020040650A1 - A method, apparatus and system for detecting urination events for livestock

Info

Publication number: WO2020040650A1
Application number: PCT/NZ2019/050104
Authority: WO
Inventors: Brendon WELTEN; Paul Robert Shorten
Original assignee: Agresearch Limited
Priority date: 2018-08-24
Filing date: 2019-08-23
Publication date: 2020-02-27
Also published as: AU2019325080A1

Abstract

The present invention relates to an apparatus, system and non-invasive methods of detecting and measuring urination events for livestock animals, such as cows. The invention involves the use of apparatus and a system in a method of detecting electrical activity of muscles at or proximate the vulval region and measuring the duration of those changes. If the characteristics of the electrical activity and their duration meet predetermined criteria, then it may be determined that a urination event has occurred for the cow. This data may be assessed and used for managing and/or minimising the potential environmental impact of nitrogen derived from urine of cows on the environment.

Description

A METHOD, APPARATUS AND SYSTEM FOR DETECTING URINATION EVENTS FOR LIVESTOCK

Statement of Corresponding Applications

This application is based on the provisional specification filed in relation to New Zealand Patent Application No. 745691, the entire contents of which are incorporated herein by reference.

Field of Invention

The present invention relates to apparatus and methods of detecting urination events for livestock animals. The invention has particular application to non-invasive techniques of detecting urination events for livestock animals, such as dairy cows, by monitoring for electrical activity and movement in the muscles associated with the urination event.

Background to the Invention

The implications of excessive nitrogen being excreted in urine by grazing livestock such as dairy cows and sheep onto farmed land is well known. Dairy farm systems in particular are prone to high nitrogen losses, largely due to only about 10 to 30% of the nitrogen consumed by a dairy cow being converted to products (in the form of milk, meat, fibre). The reminder of the consumed nitrogen is primarily excreted in urine and deposited on the soil in concentrated areas at high nitrogen application rates equivalent to about 500 to 1,200 kilograms nitrogen per hectare.

The nitrogen derived from this urine is well in excess of that required by pasture plants and after transformations in soil, it is prone to being lost via leaching or gaseous emissions pathways. Nitrogen derived from the urine of grazing animals has been found to contribute significantly to nitrous oxide emissions, ammonia emissions and nitrate leaching to groundwater. Therefore, a good opportunity exists to reduce nitrogen losses from grazed pasture land by specifically targeting individual urine patches.

There is evidence that cows exhibit repeatable phenotypic variation in urination event volume and the frequency of urinations events per day. This difference in urination event volume and daily urination frequency between individual cows can be as much as two-fold. Furthermore, the nitrogen load of an individual urination event is also highly correlated with the time from the previous event, the time of day and the duration of the urination event.

This means that cows which urinate more frequently per day coupled with a lower volume per urination event tend to excrete lower amounts of nitrogen per urination event and thus represent a lower risk to the environment. This is because pasture plants in the urine "patch" (the area of pasture onto which urine is discharged) can utilise a greater proportion of the urine nitrogen for plant growth when urine is deposited at a lower nitrogen application rate.

Conversely, for cows that have less urination events per day coupled with a greater volume per urination event, the amount of nitrogen excreted in the urine patch is higher; a greater amount of the nitrogen is unable to be utilised by pasture plants and therefore this nitrogen is vulnerable to being lost to gaseous emissions and/or being leached into waterways.

As there is little variance between individual cows in terms of the urine flow rate, knowing the duration of the urination event allows the volume of the urination event to be calculated based on existing calibration curves from urine sensor studies that indicate that urine volume is proportional to the duration of the urination event.

Even though individual cows may excrete similar total amounts of nitrogen in urine over a period of 24-hours, irrespective of whether they urinate, for example, 12 times a day versus 18 times a day, it is preferable when considering minimising urine nitrogen loading on pasture and/or losses of nitrogen from grazed pasture land, that a dairy herd contain cows that urinate more frequently per day with a lower volume per urination event resulting in lower amounts of nitrogen per urination event.

However, there can be variance in the urination nitrogen load between individual cows and individual urination events for a particular cow. This means that a single urination event should not be relied upon for determining the impact on nitrogen loading by a specific cow. It would be preferable to make this determination based on a series of urination events for greater accuracy.

Being able to measure the frequency and duration of individual urination events over a specified period of time to determine urination frequency, average volume of urine excreted per urination event and thus the amount of nitrogen per urination event, can assist in making appropriate management decisions, both at herd level and for individual cows.

The best way of achieving this to measure the duration of individual urination events, preferably over a period of time covering at least 72 hours, to determine an average for the individual cow. However, in practice, it is difficult to monitor the time, frequency and duration of individual urination events.

One method may involve manually observing the cow in the field and timing the length of any urination events that may occur. The longer the period of time the cow is observed, the more urination events are observed. Thus, a more accurate average for the length of the urination event and therefore the volume of urine excreted in that event, can be determined. A more accurate estimate of urination frequency (events/day) can also be obtained.

Cows typically urinate 12 times in a 24-hour period. This means it is not good practice to monitor the animal for a limited period of time, for example across three hours where cows would be expected to urinate only one to two times. It would be preferable that any such monitoring take place over a 24 to 72-hour period. While this may mean more accurate determination of the timing of the urination event, and estimation of any diurnal time patterns in frequency and duration of urination events, it is clearly time-consuming and not practical, particularly when dealing with more than one animal.

This approach also requires a clear field of continuous observation; this may be difficult to achieve in practice as the cow of interest is typically in close proximity to other cows of the herd. Of course, the individual cow being monitored could be isolated from the herd, but this may affect its behaviour and lead to changes in patterns, such as frequency of urination events, that could affect the accuracy and therefore potentially bias any determinations of urination parameters for that cow.

An alternative to this would be to use sensors or other equipment placed into the urinary tract. This would do away with the need for a person to watch one or more cows for extended periods of time and allow it to retain, as much as is possible, its normal behaviour.

However, care would need to be taken when securing sensors. It can also be difficult to apply invasive sensors to the urinary tracts of cows as many will exhibit avoidance behaviours. Such sensors, some having a weight of 500 to 1,500 grams, can take considerable time to locate and place. Care would need to be taken that the cow, or the person attempting to locate the sensor, is not injured when inserting or checking the operation of the sensor. This provides an extra cost and constraint to phenotyping larger numbers of animals.

There is also the difficulty of ensuring that the sensors remain in situ for an appropriate period of time. In a typical farm environment, the sensors may become detached, dislodged or malfunction as the animal gets up and down, generally ambulates around the farm or knocks into farm/milking shed fences, races or posts.

Cows can also generate large amounts of mucus that can block or hinder the operation of the urine sensors. A sustained high-mucus confined environment can lead to cow discomfort and/or infection. Another method may involve the use of indoor metabolism stalls or similar facilities to house cows. These are constructed with sensors and/or collection devices or the like that are arranged to detect and collect the excretions of the cow. This method is not practical when dealing with large dairy herds, which can comprise hundreds of individual cows. It would entail considerable expense for stalls to be built for all the individuals of the herd, so in practice, only a limited number of stalls would be available.

The farmer would select cows to go into these stalls for a period of time, diverting them as appropriate as they transit through the dairy farm. This would then require the farmer to avoid inadvertently selecting a previously tested cow to go into the stalls, which can be difficult when dealing with a large dairy herd. This process would require careful management of the herd and would be potentially very time consuming.

For temperate grazed pasture systems whereby cows graze outdoors, this approach may not be representative of normal grazing behaviours that the cow would experience in its daily life. For example, the cow is typically offered harvested feed in portable bins and animal movements are restricted when in indoor metabolism stalls. Care must then be taken when extrapolating observations derived from such indoor metabolism stalls to outdoor field conditions. In addition, metabolism stalls do not typically provide information on individual urination events; instead they provide aggregate information, typically on a daily basis (e.g. total volume of urine excreted per day).

As already noted, dairy cows can excrete similar total amounts of nitrogen in urine on a daily basis but can exhibit large variations between cows in the amount of nitrogen excreted on a per urination event basis. This variation can be harnessed to minimise the environmental impact of grazing livestock.

Object of the Invention

It is an object of the invention to provide an apparatus, system and method for detecting a urination event, its duration and frequency in one or more livestock animals, and thus determining an average volume of urine excreted per urination event and urination frequency.

Alternatively, it is an object of the invention to provide an apparatus, system and method for non- invasive measurement of the duration of urination event in one or more livestock animals. Alternatively, it is an object of the invention to provide an apparatus, system and method for determining the extent of urine volume on land that is derived from the urine of one or more livestock animals.

Alternatively, it is an object of the invention to provide an apparatus, system and method for determining the extent of nitrogen loading on land that is derived from the urine of one or more livestock animals.

Alternatively, it is an object of the invention to provide an apparatus, system and method for determining the duration of urination of one or more livestock animals.

Alternatively, it is an object of the invention to provide an apparatus, system and method for determining the frequency of urination of one or more livestock animals.

Alternatively, it is an object of the invention to provide an apparatus, system and method for a user to manage a herd of livestock animals to minimise their impact on nitrogen loading on land.

Alternatively, it is an object of the invention to provide an apparatus, system and method for classifying livestock animals for their urine nitrogen environmental impact.

Alternatively, it is an object of the invention to at least provide the public with a useful choice.

Summary of the Invention

According to a first aspect of the invention, there is provided a method of detecting a urination event in a livestock animal, the method including the steps of:

1. placing an electromyography (EMG) sensor at or proximate the vulval region of the livestock animal;

2. monitoring for electrical activity in the muscles at or proximal to the vulval region;

3. measuring the characteristics and duration of the electrical activity;

4. determining whether the characteristics and duration of the electrical activity corresponds to a urination event.

According to a further aspect of the invention, there is provided an apparatus when used in a method of detecting a urination event for a livestock animal, the method including the steps substantially as described above, and wherein the apparatus includes: an EMG sensor, wherein the sensor is configured to be attached at or proximate the vulval region of the livestock animal, and wherein the sensor includes: a data collection device; and a processor, wherein the processor is configured to record and/or measure data relating to electrical activity of the muscles at or proximal to the vulval region and duration of same.

According to a further aspect of the invention, there is provided a system when used in a method of detecting a urination event in a livestock animal, the method including the steps substantially as described above, and wherein the system includes: an EMG sensor, wherein the sensor is configured to be attached at or proximate the vulval region of a livestock animal, the EMG sensor substantially as described above; and a processor configured to correlate the electrical activity in the muscles at or proximal to the vulval region and duration of same to criteria defining a urination event and determine whether a urination event has occurred for said livestock animal.

The invention is a method, apparatus and system for detecting urination events, and their duration, in livestock animals such as cows. The invention uses electromyography techniques to detect the electrical activity of the muscles at or proximal to the vulval region, particularly those directly below the ventral commissure of the vulval folds. As the cow urinates, the apparatus monitors the duration of this electrical activity, and correlates the activity to certain pre-established criteria to determine whether a urination event has occurred. From this, the approximate volume of urine excreted by that cow during the urination event can be determined. Over a period of time, an average for urine excreted per urination event can be calculated for the cow.

This information can be used to assist in management decisions relating to the cow, for example, whether it should be removed from the dairy herd. It can also be used to provide information on the genetic correlations and heritability of urination frequency, time of urination, nitrogen load per event, urination duration and urination volume.

A livestock animal should be understood to be animals kept and raised for their value as commodities, either through their flesh (as meat) or from their by-products (milk, hides, wool).

Reference will now be made throughout the remainder of the present specification to the livestock animal being a dairy cow, i.e. cows kept for their production of milk. However, this is not meant to be limiting and the present invention may be used with other ruminant species kept as livestock including, but not limited to, sheep, goats and so on. The method involves the use of electromyography techniques for measuring and recording the electrical impulses of the muscles at or proximal to the vulval region during a urination event. In particular, the invention takes advantage of surface EMG techniques, which is ideal for monitoring the muscles in this region.

The vulval region is an area of delicate tissue that gives passage to the urogenital ducts and rectum. Therefore, in the female of the species, it should be understood to include the vulva.

In exemplary embodiments of the invention, the EMG sensor is placed at or proximate to the region directly below the ventral commissure of the vulval folds. However, this is not meant to be limiting and the EMG sensor may be located to the side of this area, particularly when used in pairs.

In dairy cows, the area directly below the ventral commissure of the vulval folds is relatively free from hair and needs minimal preparation for use with the present method and apparatus. However, this may not be case for all animals with which the invention may be used, and some preparation, such as hair removal, may be required. An added advantage to using the region directly below the ventral commissure of the vulval folds of the dairy cow is that, for the majority of the time the EMG sensor is in place, it is largely covered and protected from the elements and general disturbance by the animal's tail.

A healthy dairy cow urinates on average around 12 times a day, although this is dependent on its diet. Each time a cow urinates should be understood to be a urination event. In healthy dairy cows, at least 95% to 99% of urination events have a duration of at least 5 seconds or more.

This is confirmed by observation trials during which six to eight animals were observed from 9am to 3pm over 6 days. It was noted that 122 out of 126 observed urination events had a duration greater than 5 seconds (97%). There was an average of 11.5 urination events per animal per day, with a mean duration of 10.8 seconds, a standard deviation of 4.1 seconds and a minimum/maximum event duration of 2 and 24 seconds respectively. Urination events of duration less than 5 seconds are not expected to pose a leaching risk (these infrequent events are expected to have a nitrogen load of around 4 grams each).

It will be appreciated that there is some muscle activity that occurs during the urination event. This generates electrical activity with specific characteristics as certain muscles contract; it is this contraction that is assessed with the present method and apparatus.

The muscles in the vulval region, particularly those directly below the ventral commissure of the vulval folds, are close to the skin and thus easily detected with the use of contact electrodes. The device measures the opening of the vulval folds due to contraction and movement of muscle in this region. Furthermore, the device measures the surface vibration that occurs as the urine stream is ejected from the urinary tract in a spiral-like stream.

A urination event must meet certain criteria in order to be identified as such. These criteria are:

1. EMG signals having a sufficient intensity;

2. EMG signals with a spectral signature sufficiently close to a specific spectral signature to within an error tolerance; and

3. EMG signals meeting criteria 1. and 2. and having a duration of 5 seconds or more.

The criteria set out above can be used to develop an algorithm to which EMG signals, either in real time or in later analysis, are applied to determine the number of urination events that have occurred during the monitoring period, the average urination event volume, and therefore the nitrogen load. It will be appreciated that urination volume is proportional to the duration of the urination event, with an average flow rate of 4 litres per minute. The nitrogen load of an individual event is also highly correlated with the time elapsed from the previous event, the time of day and the duration of the urination event.

The majority (95 to 99%) of urination events are greater than five seconds in duration and less than 60 seconds in duration. Urination-like events of less than five seconds duration, or greater than 60 seconds, are therefore excluded.

The criteria established above calls for comparison of the spectral signature of the EMG signal to a specific spectral signature for a urination event that serves as a reference. It will be appreciated that the EMG signal intensity and spectral signature may depend partially on the species, the particular anatomy of the animal, the distribution of muscle and fat tissue in this region and the fibre type distribution (e.g. fast/slow twitch fibres).

This reference spectral signature may be factored into the algorithm that analyses the EMG signals to determine whether a urination event has occurred, by comparing the similarity in the intensity of the EMG signal to that of the reference spectral signal.

The use of the identified criteria also helps eliminate other muscle activity that may occur in the vulval region that is not a consequence of a urination event. For example, the vulval region is close to the anus. Flowever, bowel movements provide an EMG signal of low intensity in the region directly below the ventral commissure of the vulval folds. This would not meet the intensity criteria established by the reference spectral signal. Furthermore, the pattern of muscle movement and surface vibration and will generate a characteristic spectral profile and duration that is different to urination events, as determined by the reference spectral signature. This allows urination events to be differentiated from bowel events.

This means it is necessary to define a reference spectral signal for a urination event. This may have been developed from EMG monitoring of one or more animals of similar age and breed. Where the animal has been previously tested, this may be a previous urination event.

Descriptive statistics and features of an EMG signal that may be used for comparative purposes include, but are not limited to, the mean frequency, median frequency, maximum, minimum, cumulative maximum, cumulative minimum, moving median absolute deviation, root mean square level, distances between spectral peaks, mean power, occupied bandwidth, signal to noise ratio, signal to noise and distortion ratio, spectral entropy, spectral kurtosis, spectral flux, spectral flatness, spectral roll, spectral centroid, time-frequency complexity measure, Mel-frequency cepstral coefficients and magnitude squared coherence. Furthermore, these descriptive statistics can be combined via a multiple regression, support vector machine, linear discriminant analysis, hidden Markov models, Gaussian mixture models, Random Forests and artificial intelligence and machine learning methods such as neural networks, deep learning and image classification convolutional neural networks to classify sound signals as urination events.

Furthermore, when one or more EMG sensors are used, the multidimensional spectra can be reduced in dimension using methods such as Principal Component Analysis, independent component analysis and singular value decomposition. The magnitude-squared coherence is a function of the power spectral densities and the cross power spectral density of two EMG signals (one being the reference signal). The magnitude-squared coherence value is between 0 and 1 and indicates how well two EMG signals correspond at each frequency. The cross power spectral density of two EMG signals provides information on the power shared at a given frequency for the two signals.

Alternatively, the distance between the power spectral density of an unknown sound source (the EMG signal detected by the EMG sensor) and a reference known EMG source can be compared using a variety of metrics. Such metrics include, but are not limited to, the Euclidian, Standardized Euclidian, Mahalanobis, City Block, Minkowski, Chebychev, Cosine, Correlation and customized distances. Such metrics may be applied to the raw power spectral density or appropriately transformed pre-processed power spectral density. Transformations include, but are not limited to, mean-centring and the standard normal variate.

Furthermore, the initial EMG data may be pre-processed using a filter such as, but not limited to, a band-pass filter to remove the effects of signals generated as the result of muscle activity elsewhere. The error tolerance or required distance to the reference EMG signal is a tuneable parameter and is dependent on the hardware, method of spectral analysis (including the sampling frequency, spectral leakage, time resolution, frequency resolution and frequency limits) and required sensitivity, specificity, precision and accuracy of the method. The reference EMG urine spectral signature, error tolerance to the reference EMG signature, required signal intensity and five second threshold are also species specific due to differences in urine flow rate, animal height and other factors.

The apparatus includes an EMG sensor which includes two or more electrodes. An EMG sensor should be understood to be a sensor that measures electrical activity by determining the potential or voltage difference between the two or more electrodes. These electrodes include a surface that is placed in contact with the skin of the cow.

Persons skilled in the art will readily appreciate suitable EMG sensors that may be used in the present invention, bearing in mind the size and location of the area to which the EMG sensor is to be attached. It is preferable to keep it as small and lightweight as possible to minimise any discomfort to the cow.

In exemplary embodiments of the present invention, the method and/or apparatus may include an additional sensor in the form of an orientation sensor. This may be integrated with the EMG sensor. For example, the orientation sensor may be a single axis accelerometer; not only are these readily available, but they are also small and compact which can help with keeping the overall size of the EMG sensor to a minimum.

In alternative embodiments, the orientation sensor may be separate from the EMG sensor and, for example, placed on the tail which, during a urination event is raised, or another part of the cow's body that moves in a specific way during the urination event. For example, a cow's spine tilts during the urination event, and the orientation sensor may detect this tilt. Alternatively, the additional sensor may be an acoustic sensor, attached to the cow's rear leg or tail, to detect sound intensity and/or frequency that is associated with a urination event. The use of an additional sensor provides some redundancy and also helps with correlating the data generated from the EMG sensor to a urination event. The additional sensor and the EMG sensor may be wirelessly communicative to ensure they are synchronised.

In exemplary embodiments of the invention, the EMG sensor includes a housing for its various components. Given its likely exposure to potentially harsh inclement weather, as well as the excretions of the cow to which it is to be attached, it is preferable that the housing be watertight.

The housing may include a base portion, which in use, is the surface of the EMG sensor that is placed in contact with the cow.

The base portion may include an attachment surface to which a bonding agent, such as high- strength adhesive, can be applied. Alternatively, the base portion may have a previously prepared adhesive layer which is activated prior to being attached to the cow by removing a shielding strip.

It will be appreciated that the base portion also includes the contact surface of the electrode of the EMG sensor.

In some embodiments, the user attaching the EMG sensor may clean or otherwise prepare the area to which it is to be attached. In most cases, this will simply involve wiping the intended area of contact with an appropriate cleaning solution, such as a mild detergent or alcohol-based solution.

Although the region directly below the ventral commissure of the vulval folds is substantially hairless, any hair that is present may be removed through shaving. This may improve the bonding of the EMG sensor to this region.

The EMG sensor should be understood to include a processor, such as a programmable logic controller (PLC) or processor.

In exemplary embodiments of the invention, the processor is configured to measure and record data relating to muscle activity, and in particular, the electrical activity associated with the contraction of the muscles of the vulval region, particularly those located directly below the ventral commissure of the vulval folds and the duration of such activity.

In exemplary embodiments of the invention, the processor is configured to analyse the data and determine whether the electrical activity associated with the contraction of the muscles of the area of interest and the duration of such activity should be correlated with the criteria 1 to 3 set out above defining a urination event and be identified as such. However, it should be appreciated that in some embodiments of the invention, the analysis of the measured and recorded data may be performed by a central processing station or computer.

The EMG sensor should be understood to include a data collection device to collect data relating to the electrical activity of the muscles of the vulval region over a period of time and store it for later retrieval and analysis.

In exemplary embodiments of the present invention, the data collection device is a hard drive or memory device connected or otherwise linked to the processor.

In exemplary embodiments of the present invention, the EMG sensor includes a power source in the form of a battery. For ease and expense, lithium button cell batteries are preferred but this is not meant to be limiting. The batteries may be larger (or smaller), depending on the size of the housing of the EMG sensor. However, it will be appreciated that smaller batteries are preferred since this allows the size of the housing and the overall weight of the EMG sensor to be kept to a minimum and be less obtrusive to the animal.

In some embodiments of the invention, the EMG sensor may include means for wirelessly transmitting data relating to muscular activity, either in real time or at regular intervals (for example, at times of milking or as the cow ambulates past a specific location), to a remote processing station for analysis. However, it will be appreciated that this may place additional demands on available power for the EMG sensor.

In use, the user will attach the EMG sensor to the vulval region, and preferably directly below the ventral commissure of the vulval folds of the cow to be monitored. If desired, an additional sensor, in the form of an orientation or acoustic sensor may also be attached.

Once activated, the EMG sensor will detect and record data relating to muscle activity, and in particular, the electrical activity associated with the contraction of the muscles of the region directly below the ventral commissure of the vulval folds and the duration of such activity. Over time, this would build up a profile for the animal.

After a desired period of time, typically 72-hours, the user will retrieve the EMG sensor, and if present, any other sensing equipment.

The collected data can be retrieved and processed through a central processing station, such as a computer. By identifying the specific number of urination events that have occurred over the monitored period of time, an average volume of urine excreted per urination event can be determined for the cow. From this, appropriate management decisions can be made in respect to the cow.

The described method, apparatus and system is advantageous; the simplicity of attachment, with minimal preparation required, and removal of the EMG sensors allows the user to more easily assess a group of cows. Furthermore, the non-invasive manner of attachment and removal is less stressful for the animals being assessed. For scale of economies, a stockpile of EMG sensors may be built up and reused on a regular basis for groups or herds of cows.

Further aspects of the invention, which should be considered in all its novel aspects, will become apparent to those skilled in the art upon reading of the following description which provides at least one example of a practical application of the invention.

Brief Description of the Drawings

One or more embodiments of the invention will be described below by way of example only, and without intending to be limiting, with reference to the following drawings, in which:

Figure 1 is a schematic of a cow showing the approximate placement of the EMG sensor;

Figure 2 is a schematic of the EMG sensor showing its internal components;

Figure 3a is a graph of the recorded signal from the EMG sensor attached to a cow in accordance with the present invention over a first period of time;

Figure 3b is a graph of changes in acceleration recorded by an accelerometer placed at the same location as the EMG sensor over the same period of time shown in Figure 3a.

Figure 4a is a spectrogram of the EMG signal generated by the first urination event of Figure

3a;

Figure 4b is the mean power spectra for EMG signals associated with urination events; and

Figure 5 is a graph of the recorded signal from the EMG sensor attached to the cow of

Figure 3a over a second period of time.

Brief Description of Preferred Embodiments of the Invention

In Figure 1, a cow (generally indicated by arrow 100) is illustrated in a three-quarters view. The approximate area of the vulval region (dashed lines) is relatively hairless and ideal for placement of an EMG sensor (102). The EMG sensor (102) is attached to the cow (100), preferably immediately below the ventral commissure of the vulval folds. Care needs to be taken to ensure that both electrodes of the EMG sensor are in contact with the skin. If necessary, the area of attachment may be cleaned with an appropriate solution, such as a mild detergent or alcohol-based solution.

Illustrated in Figure 2, the EMG sensor (102) may be a standard, off-the-shelf device such as the TrueSense Explorer™ VI.1 EMG biosensor device. This example is not meant to be limiting and other types/models of EMG sensors may be used as alternatives.

This EMG sensor (102) is four centimetres in length, which is relatively small and compact and includes a pair of electrodes (104a, 104b) that detect EMG signals as a result of the electrical activity of the muscles in the vulval region. Regardless of the length of time that the EMG sensor is in place, it must have a source of power for the processor (106) measuring and recording the data associated with the electrical activity generated as a consequence of the contractions of the muscles proximal to the region directly below the ventral commissure of the vulval folds. This power source is a built-in ultra-compact rechargeable LIR1220 battery (108).

The EMG sensor (102) also includes a memory module (110), or hard drive or similar memory device, to store the collected data for later retrieval and analysis. This is sufficient to record for 11 hours or through wireless transfer for 24 hours. EMG signals are recorded at 512 Hz and the accelerometer data is recorded at 8-32 Hz. The EMG signal is acquired with a 2-electrode (bipolar) signal acquisition from electrodes located three centimetres apart with a 2000X high gain amplifier at a 13-bit effective dynamic range.

The EMG sensor (102) includes a housing (112) to ensure that its components are kept protected from fluids. It will be appreciated, given its point of attachment to the cow, that urine and faeces may come into contact with the housing and so it needs to be as impervious as possible to this.

The housing (112) may be manufactured from a transparent and durable plastics material; not only does this ensure the housing is structurally sound and lightweight, but also allows visual inspection of the internal components of the EMG sensor (102) once it is in place.

The housing (112) may include visual markings, such as a serial number, or be provided with a writing panel for indicia to be added. This allows the user to correlate a specific EMG sensor (102) with a specific cow. For example, the user may note the cow's ear tag number onto the writing panel. In most cases the tail of the cow will obscure the EMG sensor. Should the EMG sensor become detached from the cow, it may be quicker to identify the affected cow by inspecting ear tags as opposed to checking for the absence of the EMG sensor.

The housing (112) is also relatively low profile. This is to help minimise any discomfort to the cow and reduce the risk that the EMG sensor (102) may become dislodged from the region directly below the ventral commissure of the vulval folds through contact from the animal's tail.

The base (114) of the housing (112) may be configured for expeditious attachment to the cow. For example, it may be coated with a high-strength adhesive (not shown). The adhesive may be covered by an activation strip which is removed by the user prior to placement on the cow. Alternatively, the user may apply the high-strength adhesive to the base of the housing and to the site at which it is to be positioned.

A multitude of EMG sensors can also be located proximal to the vulval region to obtain a plurality of information that can provide extra information about the time and duration of urination events.

Regardless of the method of securing the EMG sensor (102) to the cow, it is desirable that it remain in place for at least 48 to 72 hours. This is a sufficient period of time to monitor the number and duration of urination events and determine a reasonably accurate average amount of urine excreted per urination event for the cow. However, this is not meant to be limiting; in some cases, it may be acceptable to determine a urination frequency/duration average based on data collected over a 24-hour period.

As previously discussed, a urination event must meet certain criteria in order to be identified as such. These criteria are:

1. EMG signals having a sufficient intensity;

Thus, an average duration per urination event can be determined for the cow. This in turn can be used to calculate the approximate volume of urine excreted and thus the nitrogen loading of the cow.

Urination volume is proportional to the duration of the urination event, with an average flow rate of 4 litres per minute. The nitrogen load of an individual event is also highly correlated with the time from the previous event, the time of day and the duration of the urination event. An algorithm can be developed based on these parameters and applied by a processor to the data collected from a cow fitted with EMG sensors. By comparing the data to a previously established reference spectral signature for a urination event, it can be determined whether a urination event has occurred or not. This eliminates false positives created by muscle activity associated with other types of behaviours. For example, certain activities such as tail strikes to remove flies, shivering and shaking may all cause EMG signals that are recorded and measured by the EMG sensor. However, these other behaviours exhibit EMG signals of different intensity, spectral power and duration that allow them to be distinguished from valid urination events.

The implementation of the method, apparatus and system can be seen in Figures 3a and 3b; these respectively show the EMG signal recorded by the EMG sensor over a time period of 30 seconds and the acceleration recorded by the backup orientation sensor at the same location.

In Figure 3a, a urination event is depicted through the change in amplitude of the EMG signals, this change commencing at approximately 8082 seconds and ending at approximately 8097 seconds. From this, the duration of the urination event can be determined as being 15 seconds according to criteria 1 to 3 above, which is approximately consistent with a visual observation estimate of 19 seconds for the urination event at this time.

This is confirmed by Figure 3b showing the data recorded from the backup orientation sensor, in the form of a single axis accelerometer. This illustrates a corresponding acceleration in movement of the accelerometer located directly below the ventral commissure of the vulval folds over the same time period as Figure 3a.

From this determination of the length of the urination event, the time and approximate volume of urine excreted during the event can be calculated.

The EMG signals may be expressed visually in different ways. For example, Figure 4a is a spectrogram of the EMG signal generated by the first urination event of Figure 3a; and Figure 4b is the mean power spectra for EMG signals associated with urination events.

Figure 5 demonstrates a graph of the recorded signal from the EMG sensor attached directly below the ventral commissure of the vulval folds of a cow over a second period of time from when the sensor was turned on at 7:31:45am. It should be appreciated that this EMG signal exhibits a different characteristic spectral power distribution compared to the signal in Figure 3a. There was no urination event over this period of time and this EMG measurement is not associated with a urination event according to criteria 1 to 3, as set out above. Determination of the average amount of urine excreted per urination event for a particular cow can then be used to help make management decisions in relation to that cow. For example, cows that urinate more frequently may be preferentially selected for breeding (or their sires preferentially used for breeding) as such animals may have a lower impact on nitrogen loading on pasture. Alternatively, they may be retained in the herd while cows that urinate less frequently are culled or separated from the herd into groups that would graze pasture that is remote from water ways.

Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of "including, but not limited to".

The entire disclosures of all applications, patents and publications cited above and below, if any, are herein incorporated by reference.

Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in the field of endeavour in any country in the world.

The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features.

Where in the foregoing description reference has been made to integers or components having known equivalents thereof, those integers are herein incorporated as if individually set forth.

It should be noted that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the invention as claimed herein and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be included within the present invention.

Claims

1. An apparatus when used in a method of detecting a urination event for a livestock animal, wherein the apparatus includes: an electromyography (EMG) sensor, wherein the sensor is configured to be attached at or proximate the vulval region of the livestock animal, and wherein the sensor includes: a data collection device; and

a processor, wherein the processor is configured to record and/or measure data relating to electrical activity of the muscles at or proximal to the vulval region and duration of same.

2. The apparatus as claimed in claim 1, wherein the EMG sensor includes at least one electrode.

3. The apparatus as claimed in claim 1 or claim 2, wherein the data collection device is a hard drive or memory device connected or otherwise linked to the processor.

4. The apparatus as claimed in any one of claims 1 to 3, wherein the processor is configured to analyse the recorded data.

5. The apparatus as claimed in any one of claims 1 to 4, wherein the apparatus includes a means for wireless transmission of data to a processor separate to the EMG sensor.

6. The apparatus as claimed in any one of claims 1 to 5, wherein the apparatus includes one or more of: a further EMG sensor, an orientation sensor, or an acoustic sensor.

7. The apparatus as claimed in claim 6, wherein the apparatus includes a means for wireless communication between sensors.

8. The apparatus as claimed in any one of claims 1 to 7, wherein the apparatus includes a housing.

9. The apparatus as claimed in claim 8, wherein the housing includes a base portion, wherein the base portion includes an attachment surface to which a bonding agent may be applied.

10. The apparatus as claimed in claim 9, wherein the base portion includes the contact surface of the at least one electrode of the EMG sensor.

11. The apparatus as claimed in any one of the proceeding claims, wherein the EMG sensor includes a power source in the form of a battery.

12. A method of detecting a urination event in a livestock animal, wherein the method including the steps of:

a) placing an EMG sensor at or proximate the vulval region of the livestock animal;

b) monitoring for electrical activity in the muscles at or proximal to the vulval region; c) measuring the characteristics and duration of the electrical activity; and d) determining whether the characteristics and duration of the electrical activity corresponds to a urination event.

13. The method as claimed in claim 12, wherein the EMG sensor is placed at or proximate to the region directly below the ventral commissure of the vulval folds.

14. The method as claimed in either claim 12 or claim 13, wherein the method includes an additional step of:

e) placing a further EMG sensor at or proximate the vulval region of the livestock animal.

15. The method as claimed in any one of claims 12 to 14, wherein the characteristics of the electrical activity include one or more of: intensity, spectrum, and frequency.

16. The method as claimed in any one of claims 12 to 15, wherein the livestock animal is a ruminant.

17. The method as claimed in claim 16, wherein the ruminant is a dairy cow.

18. The method as claimed in any one of claims 12 to 17, wherein the urination event is defined by certain criteria, wherein the criteria are:

a) EMG signals having a sufficient intensity; and

b) EMG signals with a spectral signature sufficiently close to a specific spectral signature to within an error tolerance; and

c) EMG signals meeting criteria 1. and 2. and having a duration of 5 seconds or more.

19. The method as claimed in claim 18, wherein the determination of a urination event involves the step of establishing a specific spectral signature for the urination event that serves as a reference.

20. A system when used in the method of detecting a urination event in a livestock animal, the method as claimed in any one of claims 12 to 18, and wherein the system includes an apparatus as claimed in any one of claims 1 to 11; the system also including a central processing station.