Identification of reproductive performance-related genes in the bovine hypothalamus and pituitary gland and analysis of the regulatory network

We explored the gene expression patterns of the pituitary gland and hypothalamus of Angus cows at different growth and developmental stages by deep sequencing the transcriptome and identified genes that affect bovine reproductive performance to provide new ideas for improving bovine fertility in production practice. We selected three 6-month-old (weaning period), three 18-month-old (first mating period) and three 30-month-old (early postpartum) Angus cows. The physiological statuses of the cows in each group were the same, and their body shapes were similar. After quality control of the sequencing, the transcriptome analyses of 18 samples yielded 129.18 GB of clean data. Clean data for each sample reached 6.30 GB. The GC content was >47.61%, and the base percentage of Q30 was at least 94.19%. We detected 13280 and 13318 expressed genes in the pituitary gland and hypothalamus, respectively, and screened 35 and 50 differential genes for each, respectively. Differential genes in both tissues were mainly concentrated in metabolism, lipid synthesis, and immune-related pathways in the 18-month-old cows compared with those in the 6-month-old cows. The 30-month-old cows presented more regulated reproductive behavior, and pituitary CAMK4 was the main factor regulating the reproductive behavior during this period via the pathways for calcium signaling, longevity, oxytocin, and aldosterone synthesis and secretion. Nine Angus cattle at the ages of 6, 18 and 30 months from the Changsha Institute of Animal Science were selected and divided into 3 groups according to age, with 3 cows per group.