Factors affecting recording methane emission phenotypes of composite and crossbreed beef cattle grazing tropical and subtropical rangelands of northern Australia

Abstract

Rearing cattle for beef production has a considerable contribution to global human related methane emissions. Cattle can be selectively bred to reduce methane production, but this requires accurate measurement of current methane emissions at an animal level. This study recorded short term breath measurements utilizing GreenFeed units (GFU) (C-Lock, USA) a commercially available system to observe methane production from cattle across 7 trials at 4 sites in northern Australia. This paper, undertaken to enable a broader genetic study, identifies and quantifies the main factors influencing methane production from individual cattle grazing tropical and sub-tropical rangelands using GFUs, also considering some environmental and location differences. Several factors were identified that contributed to variance in methane production these included the specific GFU, visitation frequency, air temperature, initial weight and available forage. Accurate recording of methane from individual grazing animals on subtropical and tropical rangelands identifies differences in production and selection for lower methane production in these environments to be undertaken.