Greenhouse gas mitigation opportunities with immediate application to pastoral grazing for ruminants

Many of the greenhouse gas (GHG) mitigating options proposed by researchers have little immediate application to ruminant production from grazed pastures. Many grazing systems have low inputs and ruminants may have infrequent human intervention, which poses a challenge for mitigating GHG. Farmers must be aware of a need for mitigation, but adoption will only occur if the benefits for profitability exceed the costs of implementation and many potential mitigants are either too expensive (organic acids), have variable responses in vivo (ionophors, oils), are impractical under extensive grazing or are unlikely to be available in the near future (vaccines, methanogen inhibitors). Practical GHG reduction will depend on improvements in animal and dietary management, selection of individuals having low emissions/unit feed eaten, and possible release of mitigants through controlled release intra-ruminal capsules.