CON = Control, 10 C = 10% Corn, 5S = 5% Sorghum, 10S = 10% Sorghum, 15S = 15% Sorghum. B. Summary of box plots revealing beta diversity CA4P associated with each treatment. The centroid (50%) and quantile (25 and 75%) values depicting the dispersion of OTUs associated with each dietary treatment. Dots indicate the OTUs associated with each animal. CON = Control, 10 C = 10% Corn, 5S = 5% Sorghum, 10S = 10% Sorghum, 15S = 15% Sorghum. The relationship among treatments is indicated in Whittaker plots (plotted as the log of the relative abundance vs. rank abundance)

with each dot representing a species learn more (Figure 2). The left and top of the graph indicate the presence of the most abundant OTUs with the bottom and right indicating the occurrence of rare OTUs. Each dot represents one species and the high steepness of the graph is indicative of unevenly distributed species. The lengths of the curves also indicate the occurrence of rare OTUs. The curves generally overlap one another in this analysis for all dietary treatments; thus, overall microbial diversity were similar. Figure 2 Rank abundance curves for each treatment. Each point represents the average relative abundance for a species, and species are ranked from most abundant to least abundant. CON = Control, 10 C = 10% Corn, 5S = 5% Sorghum, 10S = 10% Sorghum, 15S

= 15% Sorghum. Influence of DGs on fecal microbiota-phyla Four find more phyla were observed to have a response to dietary treatments (Additional file 1: Figure S1a-d). These are Synergistetes (p = 0.010), WS3 (p = 0.05), Actinobacteria (p = 0.06), and Spirochaetes (p = 0.06). A total of 24 phyla were observed distributed amongst all beef cattle on all diets (Figure 3a and Additional file 2: Figure S2). These are listed in order of average abundance and with their respective ranges (only the top ten abundances and ranges shown): Firmicutes (61%, 19-83%), Bacteroidetes (28%, 11-63%), Spirochaetes (5%, 0.0-23%), Proteobacteria Thalidomide (3.03%, 0.34-17.5%), Verrucomicrobia (1.43%,%,0.0-23.6%), Fibrobacteres (0.51%, 0.0-1.95%), TM7 (0.16%, 0.0-1.32%), Tenericutes (0.15%, 0.0-0.35%), Nitrospirae (0.11%, 0.03-0.22%), Actinobacteria

(0.09%, 0.0-0.24%), and Fusobacteria (0.0863%, 0.0166-0.3813%). Chlamydiae, Cyanobacteria, Planctomycetes, Synergistetes, Lentisphaerae, Acidobacteria, Elusimicrobia, Chlorobi, WS3, Deinococcus-Thermus, Chloroflexi, Gemmatimonadetes, and Deferribacteres were defined as low abundance phyla. Greater than 99.4% of total bacterial abundance was observed in the first 10 phyla, with several remaining phyla represented by 5 or less members. The abundance levels of the top ten phyla averaged based on dietary treatment are presented in Figure 3b. A higher relative abundance of Firmicutes was observed when compared to the relative abundance level of Bacteroidetes for DGs diets that contain 10% or more DG supplement vs. the CON and 5S diets.