Emily Conlin's MSc Defence

The objectives for this study included: (1) determining the optimum dose of biochar to reduce enteric methane (CH₄) emissions from beef cows (EXP1) and (2) determining whether biochar (Oregon Biochar Solution, White City, OR) supplementation can reduce CH₄ emissions from cows on pasture (EXP2). In EXP1, pregnant beef cows (n=8) were used in a replicated 4 × 4 Latin square study with biochar supplemented at 0, 1, 2, or 3% of dry matter intake (DMI). In EXP2, 64 cows were allocated to 8 fields (8 cow-calf pairs/field) and using a crossover design, each field was assigned to either control (no biochar) or biochar supplemented at 3% of estimated DMI. Enteric CH₄ emissions expressed in g/d, g/kg DMI, or g/kg BW were not affected (P ≥ 0.35) by biochar supplementation in EXP1 or EXP2. Dry matter intake and cow body weight were also not affected (P ≥ 0.26) by biochar supplementation in either experiment. Overall, results suggest that biochar supplementation was ineffective for reducing CH₄ emissions from beef cows fed a high forage diet or on pasture; however, animal performance was not affected.