Caprine GM-CSF (Granulocyte–Macrophage Colony-Stimulating Factor, CSF2) is a hematopoietic cytokine belonging to the colony-stimulating factor family, which also includes G-CSF (CSF3) and M-CSF (CSF1) that regulate the development, proliferation, and activation of myeloid immune cells. In goats (Capra hircus), GM-CSF is produced by activated T lymphocytes, macrophages, endothelial cells, fibroblasts, and other stromal cells in response to infection, inflammatory cytokines, or immune stimulation. Caprine GM-CSF binds to the GM-CSF receptor (CSF2R) on hematopoietic progenitor cells and mature myeloid cells, activating intracellular signaling pathways such as JAK/STAT, MAPK/ERK, and PI3K–AKT, which promote the proliferation and differentiation of granulocytes, macrophages, and dendritic cells and enhance their immune effector functions. In caprine health, GM-CSF contributes to innate immune defense and regulation of inflammatory responses, particularly in tissues such as the respiratory tract and mammary gland, where myeloid cells play key roles in controlling infection. Goats are also used as animal models for studying mycobacterial diseases, and GM-CSF–regulated macrophage responses have been investigated in caprine models of paratuberculosis caused by Mycobacterium avium subsp. paratuberculosis, helping researchers understand host immune mechanisms against chronic intracellular bacterial infections relevant to both livestock health and comparative immunology.