Bovine CCL5 (C–C motif chemokine ligand 5, also known as RANTES – Regulated upon Activation, Normal T cell Expressed and Secreted) is a proinflammatory chemokine that plays an important role in immune cell recruitment and inflammatory responses in cattle (Bos taurus). CCL5 belongs to the CC chemokine family, which includes related chemokines such as CCL3 (MIP-1α), CCL4 (MIP-1β), and CCL2 (MCP-1) that regulate leukocyte trafficking during immune activation. In cattle, CCL5 is produced primarily by activated T lymphocytes, macrophages, dendritic cells, platelets, and epithelial cells in response to infection, inflammatory stimuli, or tissue injury. CCL5 exerts its biological effects mainly through binding to the chemokine receptors CCR1, CCR3, and CCR5, triggering intracellular signaling pathways that promote chemotaxis and activation of T cells, monocytes, macrophages, eosinophils, and natural killer (NK) cells at sites of infection or inflammation. In bovine health, CCL5 contributes to immune responses against bacterial and viral pathogens, including those involved in mastitis, respiratory disease complexes, and viral infections such as bovine viral diarrhea virus (BVDV). By promoting recruitment and activation of immune cells, CCL5 helps coordinate local inflammatory responses and antiviral defense mechanisms. Because chemokine-mediated immune cell trafficking is essential for effective host defense, bovine CCL5 is studied in veterinary immunology, infectious disease research, and mastitis biology, contributing to improved understanding of immune regulation and disease resistance in cattle.