Comparison Between Non-Invasive Methane Measurement Techniques in Cattle

• Main Authors: Jagoba Rey, Raquel Atxaerandio, Roberto Ruiz, Eva Ugarte, Oscar González-Recio, Aser Garcia-Rodriguez, Idoia Goiri
• Format: Article
• Language: English
• Published: MDPI AG 2019-08-01
• Series: Animals
• Subjects: NDIR; laser; agreement; enteric emissions; interchangeability
• Online Access: https://www.mdpi.com/2076-2615/9/8/563

The aim of this trial was to study the agreement between the non-dispersive infrared methane analyzer (NDIR) method and the hand held laser methane detector (LMD). Methane (CH₄) was measured simultaneously with the two devices totaling 164 paired measurements. The repeatability of the CH₄ concentration was greater with the NDIR (0.42) than for the LMD (0.23). However, for the number of peaks, repeatability of the LMD was greater (0.20 vs. 0.14, respectively). Correlation was moderately high and positive for CH₄ concentration (0.73 and 0.74, respectively) and number of peaks (0.72 and 0.72, respectively), and the repeated measures correlation and the individual-level correlation were high (0.98 and 0.94, respectively). A moderate concordance correlation coefficient was observed for the CH₄ concentration (0.62) and for the number of peaks (0.66). A moderate-high coefficient of individual agreement for the CH₄ concentration (0.83) and the number of peaks (0.77) were observed. However, CH₄ concentrations population means and all variance components differed between instruments. In conclusion, methane concentration measurements obtained by means of NDIR and LMD cannot be used interchangeably. The joint use of both methods could be considered for genetic selection purposes or for mitigation strategies only if sources of disagreement, which result in different between-subject and within-subject variabilities, are identified and corrected for.