Abstract

Methane production from grazing animals makes a significant contribution to New Zealand’s greenhouse gas emissions and as such there is a need to compare methane emissions from different feeds and management systems. Laser Methane Detector (LMD) meters are portable, fast and relatively inexpensive and have been utilised overseas to measure methane emissions. The aim of this study was to determine whether LMD meters could be used to measure methane in grazing animals by testing it in a situation where methane production was likely to vary, in this case morning (AM) and afternoon (PM). The method used involved eight hand-reared hoggets and a small sheltered pen to minimise external air flows and enable a set distance from the LMD operator and the hoggets. The amount of methane produced in the PM was greater than the methane produced in the AM and the pattern was different with multiple smaller peaks in morning and a small number of larger peaks in the afternoon.

Thomson, B.C., Muir P.D., Ward K.R., and Smith N.B.

Hamilton, Volume 85, Hamilton, 52-54, 2025