Bos taurus Raw sequence reads

Age at first service (AFS) is a key indicator of puberty timing, reproductive efficiency, and rearing cost in dairy heifers. In this study, we investigated the genetic and transcriptomic basis of AFS in Chinese Holstein heifers. Whole-blood RNA sequencing was performed on 40 heifers selected from a larger population based on extreme AFS phenotypes and their corresponding genomic estimated breeding values (GEBVs). Specifically, two extreme groups were defined: a low-AFS group (n = 20) and a high-AFS group (n = 20). Total RNA was extracted from whole blood, and strand-specific RNA-seq libraries were constructed and sequenced on an Illumina platform to generate paired-end reads. These data support the identification of regulatory variants and candidate genes influencing puberty timing in dairy cattle.