Influence of and aqueous extract on cattle ruminal gas production and degradability .

Introduction: Mitigation of ruminant greenhouse gas (GHG) emissions is crucial for more appropriate livestock production. Thus, there is a need of further research evaluating feed supplementation strategies to mitigate enteric GHG emissions and other gases produced within the rumen.

Methods: This study was conducted as a completely randomized experimental design to determine the effectiveness of liquid extracts from (AZI), (CNA), or their combination (Mix. 1:1) at dosages of 0, 36, 72, and 108 mg of liquid extract/g DM substrate incubated in reducing GHG production , particularly methane (CH4), from the diet of steers during anaerobic incubation in rumen fluid. Total gas production, CH4, CO, H2S, and fermentative characteristics were all measured .

Results: Treatment AZI at a dose of 108 mg of liquid extract/g DM substrate produced the highest ( < 0.05) gas volume at 6 h, whereas CNA at a dose of 72 mg of liquid extract/ g DM substrate produced the least ( < 0.05) at 6 and 24 h, and Mix. at a dose of 72 mg of liquid extract/g DM substrate produced the least (P < 0.05) at 48 h. In addition, CH4 levels at 6 and 24 h of incubation (36 mg/g DM substrate) were highest ( < 0.05) for CNA, and lowest ( < 0.05) for AZI, whereas this variable was lowest ( < 0.05) at 72 mg of liquid extract for CNA at 24 and 48 h. At 6 and 24 h, CO volume was highest ( < 0.05) for AZI at 108 mg of liquid extract and lowest ( < 0.05) for Mix. at 72 mg of liquid extract. Treatment Mix. had a high ( < 0.05) concentration of short chain fatty acids at 72 mg of liquid extract/g DM of substrate.

Discussion: In general, herbaceous perennial plants, such as AZI and CNA, could be considered suitable for mitigating enteric GHG emissions from animals. Specifically, the treatment Mix. achieved a greater sustainable reduction of 67.6% in CH4 and 47.5% in H2S production when compared to either AZI. This reduction in CH4 might suggest the potential of the combination of both plant extracts for mitigating the production of GHG from ruminants.