Sniffer SOP

Introduction

This document is the report obtained from the presentations, talks, chats and discussions of the Zoom meetings on 23rd 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) or nitrous oxide (N2O). Gas cards used to estimate CO2 and CH4 concentrations have different sensitivities: 0-10.000 ppm for CH4 and 0-50.000 ppm for CO2. 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 can manage up to a maximum of 130 animals.  

If there are power cuts, the system restarts automatically when power is restored.

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.