Grazing steers partner with their rumen microbiomes to efficiently convert plant-derived carbohydrates into meat. Considering the socioeconomic importance of the beef industry, it is critical to develop strategies that maintain quality while lessening negative environmental impacts. Diet supplementation and hormonal implants have been shown to variably impact methane emissions and animal performance. The response of the rumen microbiome to such treatments remains unknown. Here, we will analyze 16S rRNA gene amplicon sequencing of the rumen microbiome from grazing steers across four treatment groups: diet supplemented, hormonal implanted, combined diet and implant, and no intervention. The diet, implant, and combined treatment showed no significant impact on methane emission or N excretion over the 90-day grazing trial. Given this lack of difference, we hypothesize the rumen microbial communities will not be different across treatments. However, we hypothesize the 90 days of grazing will significantly alter the rumen microbiome. Results from this study will provide insight into rumen microbiome dynamics during the life cycle of a grazing steer, further informing management strategies.
