Non-invasive individual methane measurement in dairy cows

Area of Science:

• Animal Science
• Environmental Science
• Agricultural Engineering

Background:

• Reducing methane (CH4) emissions in dairy production is vital for environmental sustainability.
• Accurate, individual cow CH4 measurement techniques are needed but current methods are often impractical.
• Understanding genetic and nutritional factors requires reliable CH4 output data.

Purpose of the Study:

• To validate a non-invasive photoacoustic IR spectroscopy (PAS-F10) system for measuring individual cow CH4 output.
• To assess the between-animal variation in CH4 emissions.
• To compare PAS-F10 estimates with traditional calorimetric chamber measurements.

Main Methods:

• Utilized a portable photoacoustic IR spectroscopy (PAS-F10) system for CH4 measurement in 115 Nordic Red cows over two years.
• Calculated daily CH4 output using a carbon dioxide tracer method.
• Validated PAS-F10 data against open-circuit indirect respiration calorimetric chambers and prediction models using concordance analysis.

Main Results:

• The daily CH4 output averaged 555 l/day, with significant variations influenced by dry matter intake, milk yield, lactation stage, and diurnal patterns.
• PAS-F10 estimates showed good agreement with chamber measurements (concordance correlation coefficient of 0.84).
• Combining bi-weekly PAS-F10 measurements improved CH4 output estimation accuracy, with repeatability ranging from 0.40 to 0.46.

Conclusions:

• The PAS-F10 system provides a reliable and non-invasive method for individual cow CH4 measurement.
• The system's accuracy and practicality support large-scale monitoring for environmental footprint reduction in dairy farming.
• Significant between-animal variation in CH4 output traits was confirmed, highlighting potential for selective breeding and management strategies.