placenta miRNA-seq of blcattle black cattle
placenta miRNA-seq of blcattle black cattle
The six experimental cattle used in this study were sourced from Shandong Zhaofu Animal Husbandry Technology Co., Ltd. The barns provided adequate lighting and ventilation, with suitable temperature and humidity, and all animals were maintained under consistent feeding conditions. The study protocol was approved by the Qingdao Agricultural University Institutional Animal Care and Use Committee (IACUC) (Approval No. DKY20220805, dated August 5, 2022). Placental tissues were collected postpartum, and their length, width, thickness, and weight were measured. Cotyledon tissues from the same anatomical location were collected and stored in liquid nitrogen at -80°C. calf birth weight, body height, chest circumference, and waistline were recorded. Based on placental weight, the cattle were divided into Group P (≥5.5 kg, n=3) and Group S (<5.5 kg, n=3). After total RNA was extracted by Trizol reagent kit (Invitrogen, Carlsbad, CA,USA), the RNA  molecules in a size range of 18–30nt were enriched by polyacrylamide gel  electrophoresis(PAGE). T Then the 3' adapters were added and the 36-48nt RNAs were enriched.  The 5' adapters were then ligated to the RNAs as well. The ligation products were reverse  transcribed by PCR amplification and the 140-160bp size PCR products were enriched to  generate a cDNA library and sequenced using Illumina HiSeq Xten by Gene Denovo  Biotechnology Co. (Guangzhou, China).