Bovine Midkine (MK) is a heparin-binding growth factor and cytokine that plays important roles in cell growth, survival, and tissue repair in cattle (Bos taurus). Midkine is expressed during embryonic development and in certain adult tissues, particularly in response to injury, inflammation, or stress. Bovine midkine interacts with several cell surface receptors, including receptor-type protein tyrosine phosphatase ζ (PTPRZ1), low-density lipoprotein receptor–related protein (LRP), and integrins, activating intracellular signaling pathways such as MAPK, PI3K–AKT, and NF-κB that regulate cell proliferation, migration, and survival. Through these mechanisms, midkine contributes to processes including tissue regeneration, angiogenesis, immune cell recruitment, and inflammatory responses. In cattle, midkine is associated with developmental processes, tissue repair, and immune regulation in response to injury or infection. In cell culture, recombinant bovine midkine is commonly used to stimulate cell proliferation and migration, study growth factor signaling pathways, and investigate mechanisms of tissue repair and inflammatory signaling in vitro. Bovine midkine is also studied in veterinary and comparative biomedical research to better understand growth factor–mediated regulation of development, inflammation, and tissue regeneration.