Methane Detector in Ruminents ThiphaineBruder, Benoit Rouille, - - PowerPoint PPT Presentation

Towards a robust protocol for enteric methane measurements using a hand held Laser Methane Detector in Ruminents

ThiphaineBruder, Benoit Rouille, Tianhai Yan, Mizeck G.G. Chagunda Speaker: Mizeck Chagunda

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Laser Methane Detector in Dairy Cows

Thiphaine Bruder, Benoit Rouille, Tianhai Yan, Mizeck Chagunda

Why Methane?

• Methane (CH4) is produced as part of the

normal digestive process in ruminants.

• 89% of methane emitted from ruminants is

produced in the rumen and exhaled through the mouth and nose

• Formed in the rumen by methanogens

(archaea, protozoa, fungi and bacteria) using hydrogen and CO2

Traditional Methods

• Respiration

calorimetry chambers

• Tracer Gas

Techniques

• Sniffer technologies
• Micro Met Technique

Laser Methane Detector

• Based on infrared

absorption spectroscopy

• Using a semiconductor

laser as a collimated excitation source

• Employs second

harmonic detection of wavelength modulation spectroscopy to establish methane concentration

What we know so far?

Breath cycles

200 400 600 800 1000 1200 1400 1600 100 200 300 400 500 600 700 cow1953 200 400 600 800 1000 1200 1400 1600 100 200 300 400 500 600 cow1814

Breath Eructation

Correlation with the Chamber

0.00 100.00 200.00 300.00 400.00 500.00 600.00 700.00 800.00 900.00 1000.00 20 40 60 80 100 120 140 160 5 50 500 LMD Methane, ppm Chamber Methane, log10 ppm

Dairy Cows Sheep

y = 0.6983x + 114.95 100 200 300 400 500 600 700 100 200 300 400 500 600 700 800 Laser Methane Detector (ppm) Metabolic Chamber (ppm)

• Sensitivity and specificity for cows were

95.4% and 96.5%.

• For sheep, sensitivity was 93.8% and

specificity was 78.7%.

New Questions

• Which data do we extract?
• When should we measure?
• How long should we measure?

What data to extract?

Raw LMD data (ppm) Processed LMD data (ppm) Chamber methane (ppm) Chamber methane (g/day) Min 24 12 85 Max 49287 237 177 170 Mean 125.3 114 84.7 127.8 Variance 294656.9 2020.0 519.3 240.2 SD 542.8 45 22.8 15.5

N = 44208 for LMD and 44208

Distribution of Raw LMD data

Distribution LMD after Outliers

Density Distribution Chamber

What data to extract?

Raw LMD data (ppm) Processed LMD data (ppm) Chamber methane (ppm) Chamber methane (g/day) Min 24 12 85 Max 49287 237 177 170 Mean 125.3 114 84.7 127.8 Variance 294656.9 2020.0 519.3 240.2 SD 542.8 45 22.8 15.5

N = 44208 for LMD and 44208

When to measure?

0.1 0.2 0.3 0.4 0.5 0.6 0.7 Standing and moving a lot Lying and Eating Lying Standing and Eating Lying and Ruminating Standing Standing and Ruminating

r Activity

95% DataSet 99% DataSet

How long should we measure?

• Measurement duration had a significant

effect (p<0.01) on the concentration of methane measured by LMD

• 60s measurements significantly low

(p<0.001)

• LMD measurement window of at least 3

minutes long, recommended

Relationship to g/day chamber methane

50 100 150 200 250 300 80 90 100 110 120 130 140 150 160

LaserWindow (ppm) Chamber (g/day)

𝐃𝐢𝐛𝐧𝐜𝐟𝐬𝐡𝐞𝐛𝐳 = 𝐌𝐛𝐭𝐟𝐬𝐗𝐣𝐨𝐞𝐩𝐱 + 𝟐𝟑𝟖. 𝟑𝟐 𝟑. 𝟏𝟏 R² = 0.42 and r = 0.65

Conclusion

• LMD is a promising proxy for measuring

enteric methane

• Need to understand the data
• Build on what we know to develop a robust

protocol for measuring enteric methane using LMD.

…thank you for your attention

Relationship to conc.(ppm) chamber methane