Sniffer SOP

NOTE: This version of Section 20 has been approved by the working group's Chair. Please be aware that further revisions may occur before final review and approval by the Board and ICAR members per the Approval of Page Process.

Introduction

This document is the report obtained from the presentations, talks, chats and discussions of the Zoom meetings on 23^rd February 2023. In both meetings an introduction was made about the ICAR Feed&Gas Working Group, the objectives of the Working Group, including the revision of the guidelines (Section 20 - Recording Dairy Cattle Methane Emission for Genetic Evaluation) published two years ago. Moreover, the aim of the meeting was to share knowledge on Sniffer standard operating procedure including tips, tricks and trouble-shooting data recording using Sniffer.

Accurate measurement of methane emissions in ruminants is crucial to develop robust national or international greenhouse gas emission inventories and to evaluate mitigation strategies for their reduction. Over years many instruments and techniques have been developed and used for research purposes. Between all instruments and techniques available, Sniffer method has assumed significance. Sniffer has been developed to measure and collect data about methane (CH₄) and carbon dioxide (CO₂) emissions in the breath of ruminants during milking and/or feeding. The feed bin might be in an automatic milking system (AMS) or in an automatic feeding system (AFS). Before considering all features, advantages and disadvantages of the system, it is important to remember that they have been originally designed to detect dangerous gas leaks. Breath-sampling methods are non-invasive because, once installed, animals are unaware of the equipment and animals are in their normal environment. Animals follow their normal routine, which includes milking and feeding, so no training of animals, handling or change in diet are required. Equipment is relatively cheap and running costs are negligible. In Sniffer method, gases are continuously sampled into a sampling tube installed in the feed bin or through. The other end of the sampling tube is connected to an infrared CH₄ and CO₂ concentration analyser. Data are collected every 1-5 seconds by the Sniffer.  

This report is organized into five different paragraphs as follow:

Equipment description

On the market several suppliers of this product are available, but all systems share the same basic structure consisting of: gas meter, pressure inlet, flow meter, pressure outlet and a tube to suction with filter. It is essential to have a filter at level of the suction tube to avoid clogging of the cylinder with dust, saliva or feed. In the tube between the cylinder and the gas meter, whose diameter is 2-4 mm, one or more filters can be inserted which ensure the removal of impurities and debris from the animal’s breath. For the correct functioning of the system and for the collection of good quality data, the aspiration pump must work with an aspiration volume of 0.5-1.5 L/s. In more complex systems and to deal with particular needs (e.g., high environmental humidity) a dryer tube can also be inserted. Generally, Sniffer systems are provided of at least two gas meters: one for the methane (CH₄) and one for carbon dioxide (CO₂); further gas meters could be available, e.g., oxygen (O₂), nitrous oxide (N₂O) and water (H₂O). Gas cards used to estimate CO₂ and CH₄ concentrations have different ranges, depending on which sensor is used and how it is calibrated. Generally for CO₂ it is best to have a range between 0-25.000ppm, sensors with a range of 0-20.000ppm or 50.000ppm are also functional. For CH₄ a range of 0-2.000ppm or 0-5.000 ppm is generally used. Internet connection is guaranteed through a 5G modem or through a Wi-Fi router. Internet connection allows data storage or download. Connections problems can occur; therefore, a hard disk can be provided to ensure data still collected when connection is lost.

It is important to install the Sniffer sampling tube in a position that is not so visible to the animal to avoid frequent damages.

One unit, when installed in the automated milking system (AMS), can measure as many animals as the capacity of the AMS, generally up to 130 animals per day. Sniffers can also be installed in concentrate feeders. This is not often done as it does not give you simultaneous milking records and because concentrate feeders are generally more open that the AMS. Which means there is more influence on the measurements by for example the wind.

If there are power cuts, the system restarts automatically when power is restored. Some systems have a battery included to operate the system during a power cut.

Overview of commercially available sniffers

Currently there are different devices on the market that can be used as a sniffer. This section gives an overview of the different sniffers.

Agscent

Agscent is a company based in Australia, you can find their website here. They have developed the Agscent Air, current model: GHG 2100. This device uses a TDL (Tunable Diode Laser) sensor for CH4 and a NDIR (Non-Dispersive InfraRed) sensor for CO2. With a measurement range of 0-20.000ppm for CO2 and 0-40.000ppm for CH4. The datasheet for this device can be downloaded here and you can find the device on the website here. Currently this device is used in Australia and the USA. They have also developed the agscent x optiweigh, which combines the sniffer sensor with a weighting station for in the pasture. The datasheet for this device can be downloaded here and you can find the device on their website here. Currently these combined devices are being used in Australia.

The Agscent Air falls into the middle price range for a sniffer, for more information please contact Daniela Carnovale (daniela@agscent.com).

Arcoflex

Arcoflex is a company based in Australia, you can find their website here. They have developed a sniffer device different from the others currently on the market, as it is a passive device it does not require tubes to suck up the air. The sensor is directly placed in a feed bin above where the mouth from the cow will be. This sniffer is currently being used in Australia and New Zealand. Currently the version ASCH401 is available commercially, this device can only measure methane. Version ASCH402 will also include a CO2 sensor, this version is still under development. They have submitted a paper for review on device. You can download an earlier version of this paper here.

The ASCH401 and ACH402 both fall into the lower price range for a sniffer, for more information please contact Geoff Schaller (geoff@arcoflex.com.au)

Carltech

Carltech is a company based in The Netherlands, you can find their website here.They have developed a a new version of the WD_WUR sniffer, which will be tested in the SOP sniffer project. This device can measure CO2 in the range 0-50.000ppm and CH4 in the range of 0-2.000ppm, optionally a O2 sensor can be included. Currently the older models are being used in The Netherlands.

The WD_WUR falls into the lower price range for a sniffer, for more information please contact Koen Böggemann (koen@carltech.nl)

C-lock

C-lock is a company based in The USA, you can find their website here.Their development is mostly focused on the Greenfeed, but they have also developed a sniffer, the SimpleScan. This sniffer uses the exact same sensors as their GreenFeed, TDL for CH4 with a range of 0-40.000ppm and NDIR for CO2 with a range of 0-20.000ppm. According to C-Lock their CH4 sensor is precise to about 1 ppm. This device can be outfitted with optional O₂ and H₂ sensors. C-lock uses their own filtering algorithms and knowledge on finalized data for the final results. The datasheet for the SimpleScan can be downloaded here.

The simple scan falls into the higher price range for a sniffer, for more information please contact Robert Whittington (rwhittington@c-lockinc.com)

Gasera

Gasera is a company based in Finland, you can find their website here. They have developed multiple gas analysers, of which the Gasera one pulse can be used to measure CH₄ and CO₂. This device can be used for many different application as it can measure up to 9 gasses and H₂O. Their sensor is based on combining the cantilever enhanced photoacoustic detection technology with a broad band IR source and narrow bandpass optical filters. It measures CO₂ in the range 0,3 – 30.000ppm and measures CH4 in the range 1-100.000ppm. Both ranges can be configured to achieve the detection performance required. The datasheet for this device can be found here and you can find the device on the website here.

They have also developed the Gasera one GHG, this device can measure CH₄, NO₂ and H₂O, but no CO₂. This device is based on combining the cantilever enhanced photoacoustic detection technology with quantum cascade laser source operating at a Mid-IR fundamental spectral absorption line of CH₄ and N₂O. This combination provides very high sensitivity (ppb level) to reliably measure ambient background levels of greenhouse gases methane (CH₄) and nitrous oxide (N₂O). It has a recommended recalibration period of 12 months. You can download the datasheet for this device here and find more information on the website here.

The Gasera one pulse falls into the higher price range for a sniffer, for more information please contact gasera here.

Gasmet

Gasmet is a company based in Finland, you can find their website here. They have developed multiple gas analyzers for many different applications, the GT5000 can measure up to 50 gasses. It can measure both CO₂ and CH₄ up to 100.000ppm, the range can be adjusted to what is needed. This device uses a FTIR (Fourier Transformed InfraRed) sensor. The benefit of this sensor is that it can easily detect other or unknown gasses which you were not aware of and you can then add them to your detection. You can download the datasheet for this device here and find more information on the website here.

The GT 5000 falls into the higher price range for a sniffer, for more information please contact Jockum Törnqvist (jockum.tornqvist@gasmet.fi)

Edinburgh Sensors

Edinburgh Sensors is a company based in the UK, you can find their website here. They develop sensors that can be used for measuring CH₄ and CO₂ in the breath of ruminants. They produce the boxed gascard and the guardian NG. These sensors can be used to build your own sniffer, by combining the sensors with, amongst others, a datalogger and waterproof casing. The measurement range is dependent on which type of gascard for CO₂ you include in the build. Currently the completely assembled Guardian sniffers are being used in Finland, Denmark and Spain.

There are companies that can build the complete sniffer from these sensors. One of these companies is DuoTec, you can find their website here. Contact person for inquiries for this company would be: Rasmus Bendsen (raw@duotec.dk)

Another company that can build a sniffer from these sensors is Bramtech, they build the sniffers that are currently used by Aarhus University. They currently have no plans to expand further into this business.

Most often the Guardians are assembled in house by the research groups themselves.

In general this device, once completed falls in the lower price range for sniffers. You can contact Edinburgh Sensors here.

Tecnosens

Tecnosens is a company based in Italy, you can find their website here. They have developed the MooLooger, currently there are two versions available, the MooLooger standard and the MooLogger advanced. The MooLogger has a measurement range of 0-5.000ppm for CH₄ and 0-50.000ppm for CO₂ and uses a NDIR sensor. Optionally this device can measure O₂ in the range of 0-25.000ppm. Currently the MooLogger is being used, on small or large scale, in Italy, Spain, Canada, USA, Switzerland and Uruguay. You can download the datasheet for this device here and find more information on the MooLogger on the website here.

The MooLooger falls in the lower price range for a sniffer, for more information please contact Greta Bonacina (gbonacina@tecnosens.it)

Nikira labs

Nikira labs is a company bases in the USA, you can find their website here. They have developed the CH₄/CO₂/H₂O analyser. This device has a measurements range of 100-20.000ppm for CO₂ and 1-20.000ppm for CH₄ and can optionally detect H₂O in the range of 500-20.000 ppm. The datasheet for this device can be downloaded from their website here.

The CH₄/CO₂/H₂O analyser falls into the higher price range for a sniffer, for more information please contact Nikira Labs here.

La Trobe Uni

The research institute, as a part of La Trobe university based in Australia, has developed a sniffer inhouse, you can find their website here. They are still working on commercializing their sniffer device.

When commercialized they aim to have the sniffer fall into the lower price range, for more information please contact Aniruddha (Ani) Desai (A.Desai@latrobe.edu.au)

Comparison of technical details of commercially available sniffers

As part of the DNK-NLD project Wageningen Livestock Research has collected technical information on all commercially available sniffers directly from the companies. An excel file showing these details for all the sniffers can be downloaded here

Experimental protocols

No particular experimental protocols are applied. Once installed, the system runs continuously.

Change in diet are not required.

Training and adaptation period

Training, handling or adaptation period are not required.

Problems faced and upgrades

Device waterproof

Sniffer devices are not always completely waterproof. Considering that there is electrical wiring inside and that in some cases the intervention of a technician is necessary, it is important to choose an IP65 box or to equip the Sniffer box with a waterproof coating.

Clogging problems

To avoid clogging of the pipes, ideally a venting hose isprovided . This pipe is connected to the compressed air outlet pipe of the AMS. When the gate of the milking robot opens, allowing the animal to exit, compressed air is blown into the venting hose. This air flow in the direction of the cylinder helps to avoid clogging.

Animals identification

Antenna for ID reader is not always successful. It is suggested to use AMS data identification and merge them later on.

Calibration procedure

In many cases problems of calibration drift can occur. It is necessary to standardize zero and span calibrating procedure.

Personell in charge of the trial

It is essential to have a good technician who monitors Sniffer's activities on daily basis and who also knows the AMS and AFS system. Among the activities that the technician must carry out: setting up, moving equipment, daily data monitoring and download, checking up on equipment at irregularities, fixing problems, downloading AMS data and ordering spare parts. If a good technician is not available, it is essential to have an alert system (sms, e-mail) of anomalies.

Filter replace

Filter obturations by dust or condensation can occur. It is possible to prevent these problems changing external filter every 15 days and change internal filter every 6 months.

Questions and answers

Q1. What’s the cost of the system?

A1. 10.000€ by Edimburgh Instruments + Duotec Sensors + Bramtech customization.

A2. 4.500€ by Tecnosens (Italy).

A3. 3.100€ by Carltech Sniffer (the Netherlands) (old generation). For new generation device we have not received a new pricing.

Q2. How many animals per Sniffer?

A1. Not more than 130 cows per Sniffer.

A2. 1 Sniffer per AMS, so no more than 60/65 cows per AMS/Sniffer.

Q3. How long does the experimental trial take?

A1. We plan to continue for many years.

A2. For genetic evaluation purposes we plan to collect data for many years.

Q4. How do you identify animals in Sniffer?

A1. We use AMS identification, easier and more accurate.

A2. We use AMS identification. It is possible to use also external RFID tag reader but it need validation.

Q5. It is necessary to have gas cards with wide detection limit (0-10.000 CH4 and 0-50.000 CO2)?

A1. Not necessary considering animals’ emission, so probably are cheaper than other gas cards with different detection limit.