The global beef industry continues to receive increasing pressure to reduce its environmental footprint, particularly regarding greenhouse gas emissions. Ruminant animals, such as beef cattle, naturally produce methane gas as a by-product of enteric fermentation. In addition to its environmental impacts, ruminal methane production also represents an inherent source of energetic inefficiency for the animal. Tannins, primarily classified as condensed or hydrolyzable, are plant-derived secondary compounds that have been explored as a natural feed additive for beef cattle due to their capacity to modulate rumen fermentation, especially with respect to methane emissions and nitrogen efficiency. Although the optimal supplementation rate of a tannin extract (TE) blend, containing both condensed and hydrolyzable tannins, for beef cattle has not been determined, low doses may hold the greatest potential. Our objective was to evaluate the dose-response patterns of a TE blend at varying supplementation rates (0.0%, 0.3%, 0.6%, and 0.9% of dry matter) on nutrient utilization and methane emissions in beef cattle using indirect calorimetry. Methane emissions were reduced at a lower rate of TE supplementation, without affecting nutrient utilization and energy partitioning. Rates beyond 0.3% of dry matter displayed a pattern of increasing methane production and decreasing fiber digestibility.

Read the full article in the Journal of Animal Science.