AU2024262750A1 - A device and system for measuring greenhouse gas emissions from animals - Google Patents

Abstract

Disclosed herein is a system for measuring greenhouse gas emissions from individual ruminants in a plurality of ruminants. The system comprises a sensing device and a computing device arranged to process the dataset utilizing the measured levels of carbon dioxide and methane to determine the greenhouse gas emissions from each individual ruminant. The device comprises a sensor for detecting the identity of a ruminant at the device; a carbon dioxide sensor; and a methane sensor. The carbon dioxide and methane sensors are configured to continuously measure an amount of carbon dioxide and methane at the device, whereby a dataset is produced that includes background environmental data and data corresponding to both respiration and eructation from each of the identified ruminants when at the device.

Description

A DEVICE AND SYSTEM FOR MEASURING GREENHOUSE GAS EMISSIONS FROM ANIMALS

Technical Field

[0001] The present invention relates to devices and systems for measuring greenhouse gas emissions from animals, particularly ruminants. The measured greenhouse gas emissions can be used, for example, to inform on farm decisions.

Background Art

[0002] Many animals, and particularly ruminants such as cattle and sheep, emit significant quantities of carbon dioxide and methane (and other gasses) during respiration and when they eructate. As methane has a carbon dioxide equivalent of around 30, eructation of methane by ruminants is a significant cause of greenhouse gas production. Indeed, it is estimated that methane gas represents about 18% of the global emissions in which agriculture is a significant source.

[0003] The biggest single factor affecting the carbon footprint of ruminants is the composition of the ruminants’ diet. Ruminants rely on microbial digestion of complex feed to meet their nutrient requirements for growth and production. During the microbial decomposition of fibrous feed, however, methanogenic archaea present in the rumen release methane. Feed and supplements that reduce the methane output of a ruminant, and thereby reduce the ruminant’s carbon footprint, have been produced and are attractive solutions because they are easily controlled and easily administered. However, the efficacy of these supplements is highly variable between ruminant types, breeds and even individual animals in the same herd.

[0004] Selecting for lower methane emitting animals is another approach for reducing methane emissions, given the known hereditability of methane emissions and that genetic progress is permanent and cumulative over generations. Genetic selection, however, requires a significant amount of date on a herd of animals in order to predict accurate breeding values.

[0005] The presence and/or amount of methane and/or carbon dioxide present in the exhaled breath of a ruminant can be used to determine information about the methane production rate of the ruminant, which can then be used to “benchmark” or compare one breed of ruminant to another breed of ruminant, or one ruminant to another ruminant. Prior art methods used for the collection of methane and carbon dioxide readings require ruminants to be placed in “chambers” which are partially or wholly sealed in order to provide a controlled environment in which to accumulate data. Alternatively, there is a known technique which utilises a series of fans to circulate air and a specific tracer gas within a defined space around the ruminant. In other words, prior art systems and methods seek to take measurements only in a controlled environment. Such a requirement adds cost and increases inefficiency.

[0006] The absence of easy-to-operate, widely available and cost-effective technologies to monitor animal emissions significantly hampers the industry's ability to measure methane (and, to a lesser extent, carbon dioxide and other gasses) at scale and implement effective mitigation practices. It would be advantageous to make methane measurement accessible, driving industrywide adoption of methane monitoring technologies and contributing to a cleaner and greener future.

Summary of Invention

[0007] In a first aspect, the present invention provides a device for measuring greenhouse gas emissions from ruminants. The device comprises: a carbon dioxide sensor having an inlet that is positionable in proximity to a ruminant attractant; a methane sensor having an inlet that is also positionable in proximity to the attractant; and a sensor for detecting the identity of a ruminant at the attractant, wherein the carbon dioxide and methane sensors are configured to continuously measure an amount of carbon dioxide and methane, whereby a dataset is produced that includes background environmental data corresponding to when a ruminant is not present and, when an identified ruminant is at the attractant, data corresponding to both respiration and eructation of the identified ruminant.

[0008] Advantageously, the device of the present invention can be used in “In paddock” applications, where operation requirements and physical access render prior art devices unreliable at best and quite often unusable. Variability in environmental conditions in outdoor environments can also pose serious challenges for some prior art devices. Over time, the device of the present invention captures data for each animal in the whole herd, which data can be compiled to produce a comprehensive indication of each ruminant’s greenhouse gas production, due to both respiration and eructation.

[0009] This device is also simpler in nature than many prior art devices and, due to its continual measurements, can produce richer datasets with more granularity than the prior art. These datasets can provide a wealth of more statistically reliable information to assist primary producers in making data-driven on-farm decisions.

[0010] As would be appreciated, accurate and repeatable measurements of methane (and other gases) emissions from large numbers of animals will provide an amount of data that will enable the thorough investigation of mitigation options, including screening animals for breeding programmes, assessment of alternative management strategies, and decreasing uncertainties associated with current greenhouse gas inventories.

[0011] In some embodiments, the carbon dioxide sensor and/or the methane sensor may be configured to measure the amount of carbon dioxide/methane every second. In some embodiments, the carbon dioxide sensor and/or the methane sensor may include more than one inlet.

[0012] In some embodiments, the device may further comprise one or more additional sensors for measuring one or more gasses such as oxygen, hydrogen, carbon monoxide, nitrous oxide and ammonia.

[0013] In some embodiments, the device may also measure one or more of temperature, wind speed, barometric pressure, humidity (e.g. at 1 min intervals).

[0014] In some embodiments, the device may further comprise a transmitter to transmit the dataset to a receiver for subsequent processing.

[0015] In some embodiments, the device may be configured to be integrated into another device, such as a weighing station, a water trough or a feed dispenser.

[0016] One of the advantages of embodiments of the device is that it can provide a cost effective, reliable and reusable device for capturing a methane and carbon dioxide sample (and, in some embodiments, other gasses) from an animal. The embodiments described herein do not require the use of sealed chambers, special ventilation systems and/or tracer gases. Indeed, they may be incorporated into any one of a number of existing devices including weight stations, or milking sheds, to name two examples. The embodiment is fully automated and does not require further data input from a farmer. The device might also be used to measure emissions at a herd level, for example in a indoor environment.

[0017] The device can provide accuracy at a level accurate enough to support decision making by farmers. Moreover, the device can be portable and thus relatively easily moved from one location to another with no need for specialist installation. [0018] In a second aspect, the present invention provides a system for measuring greenhouse gas emissions from individual ruminants in a plurality of ruminants, the system comprising: a device comprising: a sensor for detecting the identity of a ruminant at the device; a carbon dioxide sensor; and a methane sensor, wherein the carbon dioxide and methane sensors are configured to continuously measure an amount of carbon dioxide and methane at the device, whereby a dataset is produced that includes background environmental data and data corresponding to both respiration and eructation from each of the identified ruminants when at the device; and a computing device arranged to process the dataset utilizing the measured levels of carbon dioxide and methane to determine the greenhouse gas emissions from each individual ruminant.

[0019] The system of the present invention can advantageously be used to quantify the greenhouse gas emissions of individual ruminants of a herd (or flock, etc.), whilst in the paddock and with minimal intervention or maintenance required by the farmer. The dataset produced by the system is more valuable to a producer as it has a high granularity for individual ruminant emission profiles based on cumulative attendances at the device, and also distinguishes from environmental levels, above which the data corresponding to respiration and eructation from the identified ruminant can readily be identified.

[0020] Emissions can be significantly reduced through existing farm management practices such as selective breeding, feeding/grazing management, improved management of animal health, and culling of unproductive stock. However, the implementation of these management practices requires reliable and affordable technology to monitor the animal's emissions and productivity, and there are currently few technologies that allow producers to measure and manage their herd’s methane emissions.

[0021] With accurate monitoring of greenhouse emissions, as provided by the device and system of the present invention, primary producers will be able to optimise feed efficiency and livestock productivity, and positively (and measurably) work towards environmental greenhouse gas reduction goals (for philanthropic or financial reward). [0022] In some embodiments, data for each individual ruminant is accumulated to build an individual ruminant profile. Thus, each and every time the ruminant attends the device, additional data is collected, increasing the reliability of the ruminant’s data In some embodiments, data for each individual ruminant is accumulated to build a herd profile.

[0023] In some embodiments, processing the dataset may comprise distinguishing between methane from respiration and methane from eructation. In this manner, methane peaks from eructation events can be more readily identified and analysed in order to provide for an even more accurate quantification of the volume of methane produced.

[0024] In some embodiments, a ranking may be applied based on the relative greenhouse gas emission for each of the plurality of ruminants. In some embodiments, the output may be in the form of a total daily methane production. Thus, whilst the device measures the concentration (ppm) of methane in a sample, which may be sufficient for some applications, the ability to convert this concentration measurement into a relative emission rate will provide a value add to the data allowing it to be used for more purposes.

[0025] In a third aspect, the present invention provides a method for selecting male and female ruminants from a plurality of ruminants for subsequent breeding, the method comprising: determining a greenhouse gas emission from each of the plurality of ruminants; ranking the plurality of ruminants in order of increasing relative greenhouse gas emission; and selecting male and female ruminants from the plurality of ruminants for breeding based on their relatively lower ranking.

[0026] In some embodiments, ruminants having a relatively higher ranking can also be removed from the herd.

[0027] This breeding method aims to improve methane emission and profitability of livestock production through the selection of superior, low methane breeding animals, based on phenotypic and genetic merit. By implementing this breeding strategy, farmers can help to reduce their carbon footprint while still maintaining healthy and productive herds.

[0028] In a fourth aspect, the present invention provides a method for quantifying a methane suppression ability of a ruminant food supplement, the method comprising: feeding the ruminant food supplement to a plurality of ruminants; measuring greenhouse gas emissions from individual ruminants in the plurality of ruminants, both before and after the ruminant food supplement is fed to the ruminants; and determining a difference between the greenhouse gas emissions from each of the individual ruminants before and after the ruminant food supplement is fed to the ruminants.

[0029] In some embodiments, individual ruminants can be ranked in order of increasing relative difference in greenhouse gas emission. In some embodiments, ruminants having a relatively lower ranking may be removed from the herd.

[0030] This method can enable farmers to quantify a methane reduction after feeding a methane- reducing food supplement to their livestock. Such information may be useful, for example, to validate a claimed carbon credit or to identify which beasts in a herd are more or less susceptible to the effects of the feed supplement. Beasts that do not show a reduction in methane production after consuming the supplement can be culled from the herd.

[0031] Other aspects, features and advantages of the present invention will be described below.

Brief Description of the Drawings

[0032] Further features of the present invention are more fully described in the following description of several non-limiting embodiments thereof. This description is included solely for the purposes of exemplifying the present invention. It should not be understood as a restriction on the broad summary, disclosure or description of the invention as set out above. The description will be made with reference to the accompanying drawings in which:

[0033] Figure 1 is a block diagram illustrating a device in accordance with an embodiment of the invention;

[0034] Figure 2 is a flowchart illustrating a system in accordance with an embodiment of the invention;

[0035] Figure 3 is a block diagram illustrating the transformation of raw data into eructation metrics for an individual animal in accordance with an embodiment of the invention;

[0036] Figure 4 is a reading showing a typical sample of CFU in the breath of a cow, recorded with a device in accordance with an embodiment of the present invention;

[0037] Figure 5 is a screen shot of a dashboard displayed by a software application in accordance with an embodiment of the invention, where raw data is displayed; [0038] Figure 6 is a screen shot of a dashboard displayed by a software application in accordance with an embodiment of the invention, where processed data in the form of a methane output is displayed;

[0039] Figure 7 is a diagram illustrating a breeding methodology in accordance with embodiments of the present invention;

[0040] Figure 8 is a chart illustrating measured methane levels from a feed bin located in an automated dairy obtained during a trial to evaluate eructation events with dairy cattle;

[0041] Figure 9 is a chart illustrating measured methane levels for an individual animal obtaining from a feed bin located in an automated dairy obtained during a trial to evaluate eructation events with dairy cattle;

[0042] Figure 10 is a chart illustrating the measured methane levels from a chamber during a trail to evaluate the effect of feed supplements on methane emissions in a flock of sheep; and

[0043] Figure 11 is a chart illustrating the average measured methane levels of a flock of sheep fed different feed supplements.

Detailed Description of the Invention

[0044] The overarching purpose of the present invention is to determine the methane output of an animal, using methods that do not require invasive procedures, veterinarians or specialized equipment, or which are quicker and/or more reliable than conventional methods (e.g. those described above). The inventors hope that the results of their ongoing endeavours may make methane measurement accessible, driving industry-wide adoption of methane monitoring technologies and contributing to a cleaner and greener future.

[0045] The present invention may be used to implement effective mitigation practices to reduce methane emissions, working towards environmental greenhouse gas reduction goals. The present invention may be used to support breeding decisions, optimize feed efficiency and livestock productivity, supporting data-driven on farm decisions.

[0046] In other applications, the present invention may be used to research and/or validate the effectiveness of feed supplements on reducing methane emissions in animals such as cattle and sheep. In yet other applications, the present invention may be used to determine the methane output for individual animals in a herd, flock, etc. over a period of time, with this information enabling a farmer to better monitor the productivity and health of individual animals over time.

[0047] The device for measuring greenhouse gas emissions from ruminants comprises: a carbon dioxide sensor having an inlet that is positionable in proximity to a ruminant attractant; a methane sensor having an inlet that is also positionable in proximity to the attractant; and a sensor for detecting the identity of a ruminant at the attractant, wherein the carbon dioxide and methane sensors are configured to continuously measure an amount of carbon dioxide and methane, whereby a dataset is produced that includes background environmental data corresponding to when a ruminant is not present and, when an identified ruminant is at the attractant, data corresponding to both respiration and eructation from the identified ruminant.

[0048] The device may be used indoors (such as in a dairy shed, a barn, an accumulation chamber, etc.) or outside (such as in a paddock, a feedlot, etc). The device may be used for both individual and group measurements.

[0049] The device may be configured to be integrated into another system, such as a weighing station, a feed bin, an accumulation chamber, or the like. The device may be a semi-closed system to limit environmental variability. The device may sample the breath emissions from an individual animal while the animal is in the system, for example while the animal is consuming feed during feeding.

[0050] The ruminant attractant may be any suitable product that has the effect of attracting a ruminant to the device and, specifically, such that its mouth is in close proximity to the sensors’ inlets. The inventors note that attractants such as salt licks, molasses and grain would be effective for ruminants such as cattle, for example. In some embodiments, the attractant may be a staple food of the ruminant (e.g. in cases where a farmer is evaluating supplements or different diets, they may not want to add an attractant per se, as doing so may adversely affect the study).

[0051] In other embodiments, the inlets of the device may be connected to a face mask or other breath sampling device to sample the breath of an individual animal. In yet other embodiments, the device may be positioned near an extraction vent in a shed system to sample the air from a group of animals.

[0052] An embodiment of the device is depicted in Figure 1 in the form of device. The device comprises a sensor for detecting a level of methane in the air and a sensor for measuring a level of carbon dioxide in the air. The sensor for detecting a level of methane in the air may be the same sensor as used to detect a level of carbon dioxide in the air, or there may be a sensor for detecting each of the gases. Other sensors (not shown) may be used, for example oxygen sensors, hydrogen sensors, and the like.

[0053] In more detail, the device may utilise a sensor which, in one embodiment, comprises a tuneable diode laser spectrometer to measure methane. Carbon dioxide may be separately measured using an NDIR CO2 sensor (e.g. a Vaisala CARBOCAP® Carbon Dioxide Probe GMP343). In the embodiment described herein, the sensors are manufactured by Axetris (htt ://axetris.com) and in one specific embodiment, the spectrometer utilised is the LGD Compact-A CH4. It will be understood that other sensors may be utilised for the purpose of measuring both methane and carbon dioxide, and the aforementioned model is merely one example of a suitable sensor.

[0054] The device also comprises a detector for detecting the identity of an animal. Any suitable detector for detecting the identity of an animal may be used. For example, the detector may be a biometric recognition system (such as. facial recognition, colour or pattern recognition, vein patterns, etc.), a Radio Frequency Identification (RFID) reader, an optical identification device such as a barcode reader or QR code reader, or the like. In use, it is envisaged that detecting the identity of an animal enables the association of the detected methane and carbon dioxide levels with the identified animal. Further, detecting the identity of the animal enables other measurements, such as feed intake, number of visits, time and duration of each visit, animal weight, etc. to be associated with the identified animal and thereby with detected methane levels.

[0055] The device may also include other components including one or more additional sensors (not shown) for measuring one or more gasses selected from the group consisting of: oxygen, hydrogen, carbon monoxide, nitrous oxide and ammonia, as well as sensors/detectors for providing contemporaneous data relating to temperature, wind speed, barometric pressure, humidity and location, for example. An anemometer may be utilised to provide wind direction and speed which can be used to provide a flow speed for ventilation calculations. The device may also include a transmitter for transmitting the dataset to a receiver for subsequent processing (e.g. via any suitable data transfer protocol, such as Bluetooth, Wi-Fi or via an available cellular network).

[0056] In one example embodiment, the device and system may be integrated with a weighing station such as the Optiweigh™ weighing station. By simultaneously measuring the size of the animal along with the methane/carbon dioxide production, allowances can be made for the variations in size of an animal.

[0057] The system for measuring greenhouse gas emissions from individual ruminants in a plurality of ruminants comprises: a device comprising: a sensor for detecting the identity of a ruminant at the device; a carbon dioxide sensor; and a methane sensor, wherein the carbon dioxide and methane sensors are configured to continuously measure an amount of carbon dioxide and methane at the device, whereby a dataset is produced that includes background environmental data and data corresponding to both respiration and eructation from each of the identified ruminants when at the device; and a computing device arranged to process the dataset utilizing the measured levels of carbon dioxide and methane to determine the greenhouse gas emissions from each individual ruminant.

[0058] In Figure 2, a block diagram illustrating a system in accordance with an embodiment is shown. A sensor for detecting methane and a sensor for detecting a carbon dioxide level are arranged proximate to the mouth of an animal. In use, a measured level of carbon dioxide and a measured level of methane is utilised by a processor to determine the methane output for the animal.

[0059] The system comprises a processor for processing the measured level of carbon dioxide and the measured level of methane and transforming the data to calculate a methane emissions value (methane output). The computing system preferably comprises a processor, read only memory (ROM), random access memory (RAM), and input/output devices such as disk drives, input peripherals such as a keyboard and a display (or other output device). The computer includes software applications that may be stored in RAM, ROM, or disk drives and may be executed by the processor.

[0060] A communications link connects to a computer network such as the Internet. However, the communications link could be connected to a telephone line, an antenna, a gateway or any other type of communications link.

[0061] Disk drives may include any suitable storage media, such as, for example, floppy disk drives, hard disk drives, CD ROM drives or magnetic tape drives. The computing system may use a single disk drive or multiple disk drives.

[0062] The computing system may use any suitable operating systems, such as Microsoft WindowsTM or a UnixTM based operating system. [0063] The system further comprises a software application, which in the present embodiment includes a database. The software application may interface with other software applications or with a remote computer (not shown) via communications link.

[0064] It will be understood that the computing system may be a “virtual” computing system located remotely of a user, such as a virtual server in the “cloud”. Such variations are within the purview of a person skilled in the art.

[0065] The software application embodies an example of the present invention, and includes a database, the database including a list of animals, together with information such as each animal’ s breed, age, weight, genetic profile, lineage, phenotype, measured characteristics such as methane emissions, etc. and diet The database may be a standalone database or may interface with one or more other systems or platforms utilised by farmers or breeders to keep track of animals. Moreover, when the method is applied to many animals, the average error over the many animals is reduced.

[0066] For example, where the animals are cattle, the farmer may have a database of cattle in another platform, which may include functions such as livestock details, pasture and location management, feed management and events such as animal sales or purchases, births, etc.

[0067] An embodiment of the invention may be incorporated into the aforementioned database and/or software or may interact with the aforementioned software by transmitting data to the aforementioned software.

[0068] In Figure 3, there is illustrated a flowchart showing the transformation of raw data into the methane output for an individual animal and a herd of animals. The processor is provided with the raw sensor data (including measured methane level and measured carbon dioxide level, the flow rate of the sample across the sensors, flux flow rate, etc.), the data and sample time, environmental data (such as the average temperature, pressure, humidity, wind speed and direction, room ventilation rates, etc.), meta data (such as location and herd identity, macro and micronutrient profiles of the diet, etc.) and animal data (including animal identity, weight and feed intake).

[0069] The raw data may be corrected prior to transformation. For example, baseline methane and/or carbon dioxide levels associated with environmental levels and/or respiration events may be subtracted from the raw sensor data prior to transformation of the data. Alternatively, the raw data may be converted to a standard format. For example, the concentration of the gas detected during a sampling event may be converted to the amount of gas emitted per day based on the flux rate of air and/or the eructation peaks. The start and stop time for an actual sample may also need to be adjusted based on a response time of the sensor and/or the length of time it takes the sample to travel between the inlet and the sensor.

[0070] The processor analyses the raw data to identify eructation events for an individual animal from respiration values. The processor transforms this raw data into calculated metrics for each individual animal.

[0071] For example, the processor may identify the number of eructation peaks in the time period and calculate the methane eructation peak average. The inventors envisage using peak identification methods that incorporate machine learning which gives more robust peak detection with the breath data. The processor may calculate the methane area under the curve of the sample period and for the duration of the animal’s visits to the feed bin. The processor may determine the methane eructation peak maximum and minimum and the methane baseline during the sample period. The processor determines the eructation peak rise time and calculates the peak area.

[0072] The processor also determines the carbon dioxide level for each maximum methane eructation peak and the carbon dioxide baseline during the sample visit and calculates the carbon dioxide area under the curve of the sample period and for the duration of the visit. The processor can also calculate the average ppm for the methane and carbon dioxide during the sample period. The processor subsequently uses an algorithm to transform the eructation metrics into the methane output.

[0073] In some embodiments, the sample data is processed utilising an algorithm that estimates the methane production from an animal by using either the peak method or the carbon dioxide balance using the methane to carbon dioxide ratio in the air proximate the animals.

[0074] In a specific form, the data generated by a device in accordance with an embodiment of the present invention lists CH4 and CO2 values accompanied by a unique date and time stamp. The data is continuous and recorded every second for CH4 and CO2. When an animal visits the device, its EID is read and recorded as well as the animal weight. This is recorded for each measure when the animal is present. When no animal is present, no EID or weight is recorded. From this dataset is extracted a sample which is the cumulation of all measures during an individual animal’s visits. The dataset consists of regular peaks and troughs representing the inhalation and exhalation of the respiratory cycle (Figure 4). When an eructation event occurs, the individual peaks are much higher and can reach maxima that are multiples of the respiratory peaks. Usually, one or more of these eructation events are recorded in one sample. [0075] Once a sample is defined, the separation of eructation from respiration needs to occur, within the literature there has been various methods to do this including visual observation, concentration >200 ppm, assuming ppm = mg/kg), the Boxplot method, and/or one standard deviation from the mean of all values in the sample. The threshold value in the data cleaning can be adjusted accounting for dilution in the system. The threshold also allows for any samples in which environmental condition result in increased dilution of the air sample to be not included.

[0076] The data processing methodology for converting methane concentration to emission rate in embodiments utilising the peak method can be summarised as follows:

[0077] The software application may be arranged to display a dashboard to an end user, such as the dashboard shown in Figure 5, where “raw” data that identifies individual animal measures is on display. These data can be refined using the algorithms described herein to provide estimated methane and carbon dioxide emissions based on the dataset, as shown in Figure 6. [0078] In one embodiment, the algorithm may use a methane peak value method to calculate the methane output.

[0079] Another indirect method relies on estimating methane emissions during an eructation event and the frequency of eructation during a measurement period (sniffer method). In this embodiment, the processor calculates the daily methane emissions based on the main peak area of methane concentration and the peak frequency in the eructations of the animal. Gas samples are collected from the air in the feed manager of, for example, an automated milking system when the animal is milked, or a feed bin in a feedlot. The attractiveness of this approach is that emissions can be measured in on-farm conditions and on a large number of animals. There appears to be a good correlation between the “sniffer” and chamber measurements for the same animals. A suitable equation is:

Estimated CH4 emission rate (g/min) = (CH4 concentration (ppm) - background CH4) [1- EXP ( -(peak rise time in seconds / 60))]’¹ x 60 x 0.656 x 10’⁶

[0080] The algorithm may use a carbon dioxide conversion method to calculate the methane output.

[0081] In some embodiments, the sensors are utilised to collect samples of both methane and carbon dioxide in the air proximate one or more animals. In other embodiments, the sensors collect samples of methane and carbon dioxide from the air within an enclosure in which the animals are held. The raw sample data is then processed utilising an algorithm to estimate the methane output of an individual animal (or a herd) by using the carbon dioxide balance and the methane to carbon dioxide ratio in the air proximate the animals.

[0082] The algorithm utilises the understanding that most of the carbon dioxide is produced by intermediary metabolism of the animal and can be predicted. In other words, if the total carbon dioxide production and the carbon dioxide/methane ratio are known, total methane production can be calculated.

[0083] In more detail, naturally emitted carbon dioxide is used to quantify methane emission. The methane to carbon dioxide ratio in the production of air of the animal(s) in question is measured at regular Intervals and combined with the calculated total daily carbon dioxide production of the animal(s). The equation utilised is:

ER=ACxV, V= ventilation rate m³/h

[0084] In alternative embodiments a carbon balance method may be utilised, which estimates the methane production from animals by using the methane carbon dioxide ratio measured in air proximate the animals combined with an estimated total carbon dioxide production. The estimated methane production or the concentration measure, depending on the measurement method, is then utilised to create a ranking system for different animals.

[0085] The use of carbon dioxide as a quantifier gas is based on knowledge compiled over more than 100 years from experiments measuring feed requirements and feed composition. The measured feed intake can be converted to heat-production, and there is a close relationship between heat and carbon dioxide-production.

[0086] Animals at maintenance have been found, on average, to emit one (1) litre of carbon dioxide per 21.5-22.0 KJ of heat produced. Corrections can be made for lactating animals or animals gaining weight. The relation between heat production and carbon dioxide production is partly related to the amount of fat deposited or mobilized and can in practice be as low as 20.0 KJ per litre of carbon dioxide when large amounts of feed carbohydrates are converted to fat as in high yielding dairy cows. The total carbon dioxide production from stables with different animals, e.g., lactating dairy cows, dry cows and heifers, has likewise been determined by researchers working with ventilation.

[0087] The carbon dioxide method can be used to quantify methane production under different circumstances. Two examples are the total methane production from a stable with dairy cows and individual estimates for cows visiting an automated milking systems.

[0088] The expiration air of cattle contains carbon dioxide and methane in concentrations 100 and 1000 times higher than the concentrations in atmospheric air, respectively. Therefore, it is only necessary to have 5-10% of the animal’ s breath in the air being analyzed. This can easily be achieved in a stable or when individual cows visit an automated milking system. The method can potentially be developed for application to grazing cattle as approximately 95% of methane emissions from cows are excreted with expiration air and the relatively small amount emitted via the rectum can be ignored, particularly where comparative comparisons (e.g. the difference between two animals or two breeds) are made.

[0089] One disadvantage of the aforementioned technique is that the carbon dioxide production of animals is influenced by the same things as the animals’ requirement for energy. This means that the size, activity and production of the animal influences the amount of carbon dioxide produced. This is not of great importance when only the quantitative effect of some change to the animal’s feeds or supplements is being measured, in a relative sense.

[0090] Such a methodology can still fail to take into account changes in digestive and metabolic activities at the same level of feed intake, differences in feed efficiency, and variation in rumen fermentation, which can all influence the amount of carbon dioxide produced by the animal and thus affect the predicted methane emissions.

[0091] The processor can use the methane output to help determine various metrics which can be used to provide a comprehensive understanding of the environmental impact of livestock methane emissions. Additional external data, such as body wight, feed intake, milk yield, etc. may also be required to determine some metrics.

[0092] For example, the processor can use the methane output to determine the methane emission rate (production) of an animal by calculating the amount of methane emitted per animal per day. This metric may be used in research studies and can be measured using chamber systems, respiration chambers and the like.

[0093] For example, the processor can determine the methane yield of an animal by calculating the amount of methane emitted per kilogram of dry matter consumed by the animal, This metric may be used to provide insights into the efficiency of feed utilization in relation to methane production.

[0094] For example, the processor can determine the methane intensity by calculating the amount of methane emitted per kilogram of product produced (e.g. of meat, milk, etc. produced). This metric may be used to help account for productivity in relation to emissions.

[0095] For example, the processor can determine the methane emission index by calculating the amount of methane emitted per unit of product. This metric may be used to assess the environmental impact of specific livestock products.

[0096] For example, the processor can determine the methane emission factor by calculating the amount of methane emitted per animal over a specified period. This metric can be used in national inventories, or to estimate emissions at larger scales.

[0097] For example, the processor can determine the relative methane emission by calculating the amount of methane emitted relative to a reference condition or baseline. This metric can help assess the effectiveness of mitigation strategies or changes in management practices.

[0098] Similarly, the processor can use the conversion algorithm to transform the measured levels of methane and carbon dioxide for the herd of animals and provide the methane emissions (production) for the herd per day, the methane yield for the herd per dry matter consumed, the methane intensity for the herd per product produced the methane emission factor for the herd per a specified time period, and/or the methane emission index and relative methane emission for the herd. Alternatively, the processor can accumulate data for each individual animal to build a herd profile. [0099] The processor then utilises an adaptive ranking algorithm and the methane output of the animal so as to calculate a rank value for the animal.

[0100] Utilised together with the algorithm, the system provides a cost-effective and simple method to estimate methane production, which provides a commercially viable trade-off between different key parameters, namely cost, efficiency, ease of use and accuracy.

[0101] The sensor unit records the data in ppm which is sent to cloud storage, this data is then pulled to a custom dashboard. The data processing and algorithms will be undertaken once the data has been sent to remote storage.

[0102] Operation of the device and system of the present invention can provide a farmer (for example) with very useful information that can help to inform many on-farm decisions, such as those relating to breeding and feeing. One such application will be described in further detail below.

[0103] In this exemplary application of the present invention, the methane output of each animal in a population of animals is used to rank the animal compared to other animals in the population. The rank of the animal can then be used to determine whether the animal is selected for a breeding program, or whether the animal should be culled.

[0104] The breeding program comprises the steps of, for a herd of animals composed of both male and female sexes, determining, for each animal in the herd, a value that is indicative of the presence or absence of the selected characteristic, in this instance, the methane output of the animal. This value is then used to rank each of the animals in an order from the animals with the greatest value for the selected characteristic to the least value for the selected characteristic. From the herd a sub- set of male animals and a sub-set of female animals can be selected which have the greatest value for the selected characteristic.

[0105] The selected animals form part of the initial breeding pool and are entered into a database and are associated with their phenotype and methane output. This is an initial breeding pool from which a breeding pool of elite animals is developed. The selected animals are bred to produce offspring.

[0106] For each of the offspring, a value that is indicative of the presence or absence of the selected characteristic is subsequently determined and utilised to rank each of the offspring in an order from the animals. A sub-set of male offspring and a sub-set of female offspring which have the greatest value for the selected characteristic, are selected and introduced into the herd. [0107] In a first step of the ranking methodology, each animal in the herd has their methane value measured. In the context of the present specification, a measurement termed the Estimated Breeding Value for Methane (EBVM) is a relative numeric value utilised by the embodiment described herein. The value is not representative of a unit of measurement, but rather is a ranking value utilised to compare one animal to another animal.

[0108] The aforementioned breeding pool (shown in Figure 7 at 200) can be comprised of a bull to cow ratio of anywhere from 1:10 to 1:40 (which generally falls in line with accepted breeding ratios). However, for the purposes of describing an embodiment of the invention, an exemplary number is displayed in Figure 7. As per Figure 7, each year 20 bulls (204) and 400 cows (202) are selected based on their individual methane output and phenotype. Generally speaking the 20 bulls (204) and the 400 cows (202) with the lowest methane output and most desirable phenotype are selected, although it will be understood that small variations to this basic methodology may be incorporated depending on the requirements of the user - for example, when other characteristics are used in addition to methane output, it is possible to create a weighted measure for each bull and cow, with methane output being one of the factors utilised to select the relevant bulls and cows, but also including other relevant factors, such as weight, diet, breed or any other suitable characteristic that is known to affect the methane output of the animal.

[0109] Once the 20 bulls (204) and 400 cows (202) are selected, they are bred to produce the next generation of bull and cow selection candidates.

[0110] In the example given herein, if it is assumed that the pregnancy rate is 60 per cent and the pregnancies result in a sex ratio of 50%, it can therefore be assumed that an additional 120 bulls (212) and 120 cows (210) join the herd each year. As the 120 bulls (212) and 120 cows (210) mature, their relative methane output is measured and an EBVM value is calculated for each of the 120 bulls (212) and 120 cows (210). The EBVM values are transferred to the software application 118.

[0111] Once an EBVM value is calculated for the 120 bulls (212) and 120 cows (210) and entered into the software application 118, the software application 118 selects a sub-set of the low methane emitting cows and bulls that are to be transferred to the breeding pool.

[0112] In the specific example shown in Figure 7, 50 cows (206) and 20 bulls (208) are selected by the software application out of 240 offspring based on the 50 cows (206) and 20 bulls (208) which emit the lowest methane). The selected 50 cows (206) and 20 bulls (208) are then transferred to the breeding pool and the remaining 170 cattle will be culled, sold, or commercially maintained for other productivity and cashflow reasons. If young bulls and heifers rank better compared to their parents, they replace bulls and cows with a higher methane output in the breeding pool.

[0113] Overall, some cattle breeds naturally produce less methane than others, so breeding for these traits is an effective way to reduce methane emissions over time, while balancing other desirable characteristics. The breeding strategy can be used in a complimentary manner with other well-known ways to reduce methane output such as utilising specific types of feed and supplements.

EXAMPLES

Example 1

[0114] In Example 1, a proof of concept trial to evaluate eructation events (i.e. belching) in cattle using a device in accordance with an embodiment of the present invention at an automated dairy was undertaken. The device was set up in a feed bin, with the air inlet of the device in proximity to the head and mouth of the feeding cow, so as to sample breath emissions from an individual animal during feeding. The concentration of methane and carbon dioxide was recorded continuously at one second intervals and temperature, atmospheric pressure and relative humidity were recorded continuously at one minute intervals.

[0115] Methane concentration over a 24 hour period is shown in Figure 8 while data collected for a single animal over the same time period is shown in Figure 9. The device was able to show clear eructation peaks (for example at 37 minutes and 157 minutes), which were clearly differentiable from respiration.

Example 2

[0116] In Example 2, a proof of concept trial to evaluate the effect of feed supplements on methane emissions in sheep using a device in accordance with an embodiment of the present invention was undertaken. The device was set up in a semi-closed accumulation chamber in which 10 sheep were housed. Two control diets and two treatments were fed twice daily to the sheep in rotation. The concentration of methane and carbon dioxide in the chamber was measured continuously for a period of about 30 minutes, twice daily.

[0117] In Figure 10, a chart illustrating the methane chamber readings for animals fed treatment B is illustrated. In Figure 11, the average methane concentration of the four diets is illustrated. The methane sensor was found to be sensitive enough to detect small changes, and more measurements would be expected to provide more confidence in observed differences.

[0118] Also generally disclosed herein is a biological sample analysis device comprising a sensor for detecting methane and a sensor for detecting a carbon dioxide level, the sensors being arranged proximate an animal, wherein the device captures sample data including a measured level of carbon dioxide and a measured level of methane, and utilises a measured level of carbon dioxide and a measured level of methane to determine the methane output for the animal. The biological sample analysis device may further comprise a computing device, wherein the computing device utilises an adaptive ranking algorithm and the methane output of the animal to calculate a rank value for the animal. The sample data may, for example, be processed utilising an algorithm that estimates the methane production from an animal by using the carbon dioxide balance and the methane to carbon dioxide ratio in the air proximate the animals. The device may further comprise a software application arranged to display a dashboard to an end user.

[0119] Also generally disclosed herein is a method of ranking the methane output of a plurality of animals, comprising the steps of, for each of the plurality of animals, utilising a device as disclosed herein to determine the methane output of the animal, providing the methane output for each of the plurality of animals to a computing system, and utilising an adaptive ranking algorithm executed on the computing system to rank the animals dependent on the methane output of each one of the animals.

[0120] Also generally disclosed herein is a method for breeding animals to optimise for a selected characteristic, comprising the steps of, for a herd of animals composed of both male and female sexes, determining, for each animal in the herd, a value that is indicative of the presence or absence of the selected characteristic, utilising the value to rank each of the animals in an order from the animals with the greatest value for the selected characteristic to the least value for the selected characteristic, selecting from the herd a sub-set of male animals and a sub-set of female animals which have the greatest value for the selected characteristic, and breeding the two subsets of animals to produce offspring.

[0121] Throughout this specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the explicit exclusion of any other integer or group of integers.

[0122] Those skilled in the art will appreciate that the embodiments described herein are susceptible to obvious variations and modifications other than those specifically described and it is intended that the broadest claims cover all such variations and modifications. Those skilled in the art will also understand that the inventive concept that underpins the broadest claims may include any number of the steps, features, and concepts referred to or indicated in the specification, either individually or collectively, and any and all combinations of any two or more of the steps or features may constitute an invention.

Claims

CLAIMS:

1. A device for measuring greenhouse gas emissions from ruminants, the device comprising: a carbon dioxide sensor having an inlet that is positionable in proximity to a ruminant attractant; a methane sensor having an inlet that is also positionable in proximity to the attractant; and a sensor for detecting the identity of a ruminant at the attractant, wherein the carbon dioxide and methane sensors are configured to continuously measure an amount of carbon dioxide and methane, whereby a dataset is produced that includes background environmental data corresponding to when a ruminant is not present and, when an identified ruminant is at the attractant, data corresponding to both respiration and eructation of the identified ruminant.

2. The device of claim 1, wherein the carbon dioxide sensor is configured to measure the amount of carbon dioxide at its inlet every second.

3. The device of claim 1 or claim 2, wherein the methane sensor is configured to measure the amount of methane at its inlet every second.

4. The device of any one of claims 1 to 3, wherein the device further comprises one or more additional sensors for measuring one or more gasses selected from the group consisting of: oxygen, hydrogen, carbon monoxide, nitrous oxide and ammonia.

5. The device of any one of claims 1 to 4, wherein the device is adapted to measure one or more of: temperature, wind speed, barometric pressure, humidity and location.

6. The device of any one of claims 1 to 5, wherein the device further comprises a transmitter to transmit the dataset to a receiver for subsequent processing.

7. The device of any one of claims 1 to 6, wherein the device is configured to be integrated into another device, such as a weighing station, a water trough or a feed dispenser.

8. A system for measuring greenhouse gas emissions from individual ruminants in a plurality of ruminants, the system comprising: a device comprising: a sensor for detecting the identity of a ruminant at the device; a carbon dioxide sensor; and a methane sensor, wherein the carbon dioxide and methane sensors are configured to continuously measure an amount of carbon dioxide and methane at the device, whereby a dataset is produced that includes background environmental data and data corresponding to both respiration and eructation from each of the identified ruminants when at the device; and a computing device arranged to process the dataset utilizing the measured levels of carbon dioxide and methane to determine the greenhouse gas emissions from each individual ruminant.

9. The system of claim 8, wherein data for each individual ruminant is accumulated to build an individual ruminant greenhouse gas emission profile.

10. The system of claim 8 or claim 9, wherein data for each individual ruminant is accumulated to build a herd greenhouse gas emission profile.

11. The system of any one of claims 8 to 10, wherein the greenhouse gas emissions of each individual ruminant are provided in the form of a total daily methane production.

12. The system of any one of claims 8 to 11, wherein processing the dataset comprises distinguishing between methane from respiration and methane from eructation.

13. The system of any one of claims 8 to 12, wherein the device is the device of any one of claims 1 to 7.

14. The system of any one of claims 8 to 13, wherein processing the dataset comprises ranking individual ruminants in the plurality of ruminants based on the relative greenhouse gas emission from each of the plurality of ruminants.

15. The system of claim 14, wherein the ranking of the ruminants is used to select a subset of ruminants from the plurality of ruminants, wherein the selected ruminants emit a relatively low amount of greenhouse gases.

16. A method for selecting male and female ruminants from a plurality of ruminants for subsequent breeding, the method comprising: determining a greenhouse gas emission from each of the plurality of ruminants; ranking the plurality of ruminants in order of increasing relative greenhouse gas emission; and selecting male and female ruminants from the plurality of ruminants for breeding based on their relatively lower ranking.

17. The method of claim 16, wherein ruminants having a relatively higher ranking are removed from the herd.

18. The method of claim 16 or claim 17, wherein the greenhouse gas emission from each of the plurality of ruminants is obtained using the device of any one of claims 1 to 7 or the system of any one of claims 8 to 15.

19. A method for quantifying a methane suppression ability of a ruminant food supplement, the method comprising: feeding the ruminant food supplement to a plurality of ruminants; measuring greenhouse gas emissions from individual ruminants in the plurality of ruminants, both before and after the ruminant food supplement is fed to the ruminants; and determining a difference between the greenhouse gas emissions from each of the individual ruminants before and after the ruminant food supplement is fed to the ruminants.

20. The method of claim 19, wherein the ruminants are ranked in order of increasing relative difference in greenhouse gas emissions.

21. The method of claim 19 or claim 20, wherein ruminants having a relatively lower ranking are removed from the herd.

22. The method of any one of claims 19 to 21, wherein the greenhouse gas emissions from individual ruminants in the plurality of ruminants are obtained using the device of any one of claims 1 to 7 or the system of any one of claims 8 to 15.