Bovine Tumor Necrosis Factor Alpha (TNF-α) (also known as TNF or cachectin) is a proinflammatory cytokine that plays a central role in innate immune responses, inflammation, and host defense against pathogens in cattle (Bos taurus). TNF-α is a member of the tumor necrosis factor (TNF) superfamily, which includes related cytokines such as TNF-β (lymphotoxin-α), Fas ligand (FasL), CD40 ligand (CD40L), and TRAIL, molecules involved in regulating immune signaling, apoptosis, and inflammatory processes. In cattle, TNF-α is primarily produced by activated macrophages, monocytes, dendritic cells, and T lymphocytes in response to infection, endotoxin exposure, or tissue injury. TNF-α exerts its biological effects by binding to TNF receptors TNFR1 (p55) and TNFR2 (p75), activating intracellular signaling pathways including NF-κB, MAPK, and caspase-mediated pathways, which regulate cytokine production, immune cell activation, apoptosis, and inflammatory responses. In bovine health, TNF-α plays an important role in immune responses to bacterial infections such as mastitis caused by Escherichia coli or Staphylococcus aureus, as well as mycobacterial infections including bovine tuberculosis (Mycobacterium bovis), where it contributes to macrophage activation and granuloma formation. TNF-α is also involved in systemic inflammatory responses and metabolic changes during infection or stress. Because TNF-α is a key regulator of inflammation and host defense, bovine TNF-α is widely studied in veterinary immunology, infectious disease research, and mastitis biology, contributing to improved understanding of immune responses and inflammatory regulation in cattle.