Bacterial Communities and Physiology of Beef Heifers Divergent in Feed Efficiency

17 cannulated beef heifers were fed a silage-based growing ration for 10 weeks. On the final day of the trial, ruminal content was collected via ruminal cannula and blood was collected via coccygeal venipuncture. Bacterial communities in the rumen fluid were analyzed by amplifying and sequencing the V4 region of the 16S gene using the Illumina MiSeq. Rumen fluid and serum metabolomes were determined using ultra performance liquid chromatography and mass spectrometry. Residual feed intake was determined using the expected growth based on dry matter intake, average daily gain, and midtest body weight subtracted from the actual dry matter intake. Data were analyzed using QIIME 2, MetaboAnalyst 4.0, and SAS 9.4.