Application of a hand-held laser methane detector for measuring enteric methane emissions from cattle in intensive farming.

The hand-held laser methane detector (LMD) technique has been suggested as a potential method for measuring methane (CH4) emissions from enteric fermentation of ruminants in the field. This study aimed to establish a standard procedure for using LMD to assess CH4 production in cattle and evaluate the efficacy of the protocol to detect differences in CH4 emissions from cattle fed with diets of different forage-to-concentrate (FC) ratios which is known to affect CH4 emissions. Experiment 1 was conducted to establish a protocol for measuring and analyzing the CH4 emissions from cattle using LMD. In experiment 2, 30 Hanwoo growing steers were divided into three groups and fed with a diet of high FC ratio (35:65) with low-energy concentrate (HFC-LEC), high FC ratio (35:65) with high-energy concentrate (HFC-HEC), or low FC ratio (25:75) with high-energy concentrate (LFC-HEC). The CH4 concentrations for all steers were measured in duplicate according to the protocol established in experiment 1. HFC-LEC showed 49% and 57% higher CH4 concentrations in exhaled gas from respiration and eructation, respectively (P < 0.01), than LFC-HEC. In conclusion, the LMD method can be applied to evaluate differences in CH4 emissions in cattle using the protocol established in this study.