The rumen microbiome beef cattle during backgrounding

Backgrounding (BKG) significantly impacts growth and finishing performance inbeef cattle; however, the contributions of the rumen microbiome during this growth stage remainunexplored. A longitudinal study was designed to assess how BKG affects rumen bacterialcommunities and average daily gain (ADG) in beef cattle. At weaning, 38 calves were randomlyassigned to three BKG systems for 55 days (d): a high roughage diet within a dry lot (DL, n=13);annual cover crop within a strip plot (CC, n=13); and perennial pasture vegetation withinrotational paddocks (PP, n=12), as before weaning. After BKG, all calves were placed in afeedlot for 142 d and finished with a high energy ration. Calves were weighed periodically fromweaning to finishing to determine ADG. Rumen bacterial communities were profiled bycollecting fluid samples via oral probe and sequencing the V4 region of the 16S rRNA bacterialgene, at weaning, during BKG and finishing.