Swine Erythropoietin (EPO) is a glycoprotein hormone belonging to the type I cytokine family that regulates erythropoiesis, the production of red blood cells. In pigs (Sus scrofa), erythropoietin is produced primarily by peritubular interstitial cells in the kidney, with additional production occurring in the liver, in response to hypoxia or reduced oxygen-carrying capacity of the blood. Swine EPO binds to the erythropoietin receptor (EPOR) on erythroid progenitor cells in the bone marrow, activating intracellular signaling pathways such as JAK2–STAT5, PI3K–AKT, and MAPK, which promote the survival, proliferation, and differentiation of erythroid precursor cells into mature red blood cells. In swine physiology, erythropoietin is essential for maintaining normal hematocrit levels and adequate oxygen delivery to tissues, particularly during growth, physiological stress, or blood loss. Because pigs share significant anatomical, physiological, and hematological similarities with humans, they are widely used as translational animal models for studying anemia, kidney disease, and hypoxia-related disorders, and swine models have been used to investigate EPO regulation and erythropoiesis in conditions such as renal anemia and critical illness, providing insights relevant to human hematology and therapeutic EPO use.