Abstract
Worldwide, beef production systems represent a significant source of greenhouse gas (GHG), and enteric methane (CH(4)) emissions are the primary concern. The objective of this experiment was to determine whether biochar (Oregon Biochar Solution, White City, OR) supplementation can reduce CH(4) emissions from grazing beef cows. Biochar is a stable form of carbon produced through the pyrolysis of organic matter (typically forestry waste). Sixty-four cows and their calves were blocked by cow body weight and calf age, and randomly allocated to 8 paddocks, each with 8 cow-calf pairs. Using a crossover design, each paddock was assigned to one of two treatments: (1) biochar supplemented at approximately 3% of estimated dry matter intake (DMI) or (2) control (no biochar). Biochar was incorporated into a pellet containing 45% biochar, 42.5% wheat midds, 10% canola oil, and 2.5% dry molasses and fed in a portable trough once daily. Each period consisted of 28 days: 21 days for biochar adaptation and 7 days for data collection. Enteric gas emissions from each paddock were measured using C-Lock GreenFeed trailers (C-Lock Inc., Rapid City, SD, USA) with pasture DMI estimated using paddock entry/exit quadrats during each sampling week. Enteric CH(4) emissions expressed as g CH(4)/d were 249 and 260 ± 50.3 g (P ≥ 0.37) for control and biochar, respectively. Similarly, g CH(4)/kg DM and g CH(4)/kg BW were not affected (P ≥ 0.44) by biochar supplementation on pasture. Biochar supplementation did not affect estimated DMI or cow/calf body weights (P ≥ 0.15). Results suggest that biochar was ineffective for reducing methane emissions from grazing beef cows; however, measures of animal performance were not affected by biochar consumption. Further work is required to determine if type or higher inclusions of biochar can reduce CH(4) emissions from beef cattle.