Methane emissions from feedlot cattle in Australia and Canada

Abstract

Raising beef cattle in open feedlots is a well established practice in Canada and is gaining acceptance in Australia because it results in more consistent meat quality. These facilities are regional ‘hot spots’ of methane (CH4) emissions, resulting from the high stocking density and the large amount of fermentation occurring in the rumen (enteric CH4). Our objective was to compare CH4 emissions from a typical feedlot in Australia (Queensland) and in Canada (Alberta) and also to compare these against modelled emissions. Methane concentration and wind data were monitored over a portion of each feedlot and a dispersion model was used to calculate CH4 emissions during a summer period. The average CH4 emission was 166 ± 90 and 214 ± 61 g/animal.day for the feedlot in Queensland and in Alberta, respectively. The lower CH4 emission at the Queensland feedlot was attributed to the lighter weight of the cattle, and consequently their lower intake, and supplementation of the diet with lipids. The lipid effect on CH4 emissions is also speculated to cause some models to overestimate the measured CH4 emissions. A lower CH4 emission also occurred during daylight hours at the Queensland feedlot and was attributed in part to heat stress as defined by the temperature–humidity index.