First assessment of methane emission in Mediterranean Buffaloes with a smart tool: preliminary results.

Animal productions are reported to be responsible for 14.5 % of the anthropogenic greenhouse gasses emissions, especially methane (CH₄). Innovative solutions are needed to quantify the emissions from different ruminant species directly on farm to help determine optimal mitigation solutions. Portable smart tools have a big role to play in this regard. The use of a laser methane detector (LMD) in livestock was first reported by Chagunda et al., 2009. This is a hand-held device to measure CH₄ from animals in a non-invasive way and in their natural conditions. The aim of the current study was to assess the application of the LMD in measuring CH₄ emissions in Italian Mediterranean Buffaloes (IMB) and to explore possible animal and environmental factors that could influence the measurement. The LMD was used to measure CH₄ emitted with the plume in twenty adult non-productive IMB (11 females; 9 males) fed with a low input diet (F:C = 80:20) during 12 consecutive days in summer. Each animal was assessed every day for 4 minutes while standing idle without physical restrain. The weight and sex of the animals were recorded. Daily Temperature Humidity Index (THI) was calculated for the trial period. LMD output data were divided for each day and each subject into eructation/peak CH₄ (CH_E) and breathing/basal CH₄ (CH_B). A linear mixed model and Pearson’s coefficient were used to analyze the effect and correlations of the variables. The average CH_E and CH_B was respectively 84.3±42.6ppm-m and 20.4±6.5 ppm-m and a significant positive correlation was found between these (R=0.63, p<0.001). A between-subject variation was observed for both eructation and breath, CH_E (p<0.001, ε²=0.12) and CH_B (p<0.001, ε²=0.21). However, this between-subject variation was not explainable by individual differences in terms of weight and sex. Trial days significantly influenced CH_B (p<0.001), while no effect was found on CH_E. Further analysis did not find any association between CH_B and daily variation of the THI (average: 74.5±1.8; min: 71.9; max: 78.6). These preliminary results allow us to consider LMD measurements as biologically meaningful for IMB and indicate the need to build a robust protocol for measuring CH₄ emissions in this species.