Ovine 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 sheep (Ovis aries). 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, proteins that regulate immune signaling, apoptosis, and inflammatory pathways. In sheep, 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 ovine health, TNF-α contributes to immune responses against bacterial, viral, and parasitic infections, including diseases such as ovine mastitis, respiratory infections, and parasitic infestations, where it promotes macrophage activation and inflammatory defense mechanisms. While TNF-α is essential for pathogen clearance, excessive or prolonged TNF signaling can contribute to chronic inflammation and tissue damage. Because TNF-α is a key mediator of inflammatory responses, ovine TNF-α is studied in veterinary immunology, infectious disease research, and inflammatory disease models, contributing to improved understanding of immune regulation and disease resistance in sheep.