Relationships between milk production traits and brain regions. (A) Milk production traits have a significantly higher GWAS signal enrichments (−log10P) than other types of traits in 14 brain regions (CNS), except for feed efficiency (i.e., residual feed intake [RFI]). We calculate P-values between groups using Student's t-test. (B) Two fine-mapped genes, TRIM46 (top; posterior probability of causality [PPC] = 0.59) and RAB6A (bottom; PPC = 0.79), for protein percentage and milk yield, respectively, are specifically highly expressed in CNS compared with all other tissues and cell types. (C) The associations of milk production traits with brain regions and four brain endocrine tissues (i.e., stalk median eminence [SME], anterior pituitary, posterior pituitary, and pineal gland) based on the GWAS signal enrichments of tissue-specific genes detected within these brain-relevant tissues. (*) Corrected-P (FDR) < 0.1.