Genetic Determinants of Milk Production Phenotypes in Dairy Goats: A Review

Dairy goats sustain milk production across marginal environments worldwide, yet genetic improvement of milk yield and composition remains slower than in cattle, constrained by smaller reference populations and limited functional validation. This review consolidates current evidence on the genes and polymorphisms governing milk production traits in dairy goats. Whole-genome resequencing and selection-signature scans repeatedly recover a lipogenic–somatotropic core (ACSS2, DGAT2, GHR, VPS13C, PRPF6), whereas genome-wide association studies (GWASs) confirm the casein cluster (CSN1S1, CSN1S2, CSN2, CSN3) as the most reproducible determinant of protein content and DGAT1 as the principal fat-content gene. Transcriptomic, single-cell, and metabolomic analyses, together with functional dissection in goat mammary epithelial cells, resolve the regulatory networks—SREBP1, PPARG, ELF5, and non-coding RNAs—that translate genotype into phenotype. Integrating multi-omic evidence with expanded, well-phenotyped populations is essential to convert this expanding catalog into precise marker-assisted and genomic selection for milk yield and quality.