Enteric methane mitigation in ruminants through feeding

Action against climate change can be achieved through greenhouse gas mitigation, especially decreasing methane emission. Methane is naturally produced in the rumen. Decreasing enteric methane emission in domestic ruminants, including beef cattle, can be achieved through various feeding practices. However, practical solutions are limited in beef cattle because beef cows are mostly fed with forages. The use of high-concentrate diets is efficacious but it may present drawbacks related to feeding ruminants with such diets. The most promising way to reduce enteric methane emissions is the addition of lipids in the diet, linseed being probably the most efficacious lipid source. Among feed additives, calcium nitrate and 3-nitrooxypropanol have be proven to be efficacious, but their use in field conditions is questionable for the former, and too early for the latter. Tannin-rich plants decrease methane production, but their use is limited by a potential negative effect on animal performance. Other additives and biotechnologies have not shown repeatable positive effects and they are still at early stages of experimentation. It is pointed out that a technique for methane mitigation could only be adopted if there is no negative effects on performance or on other environmental parameters.