title: Sequencing of rumen microbiota in cows with different lactation days during postpartum period
design: As described in the manufacturers instructions, total microbial genomic DNA from total incubation fluid was extracted by the FastDNA  SPIN for soil kit (MP Biomedicals, Solon, USA). DNA concentration and quality were evaluated by a NanoDrop ND-2000 spectrophotometer (Thermo Scientific Inc., USA) and 1.0% agarose gel electrophoresis. Polymerase chain reaction (PCR) was used to amplify the V3-V4 region of 16S rRNA gene by pair of primers 338F (5- ACTCCTACGGGAGGCAGCAG-3') and 806R (5'-GGACTACHVGGGTWTCTAAT-10')