Bovine Interleukin-13 (IL-13) is a Th2-associated cytokine produced primarily by activated CD4⁺ T helper 2 (Th2) cells and other type 2 immune cells in cattle (Bos taurus), where it plays a central role in regulating allergic-type inflammation, mucosal immunity, and tissue remodeling. IL-13 signals through receptor complexes composed of IL-13Rα1 and IL-4Rα, activating JAK/STAT6 pathways that drive alternative macrophage activation, modulation of pro-inflammatory cytokine production, mucus secretion, and IgE-associated immune responses. In bovine health, IL-13 is particularly important in responses to parasitic infections such as gastrointestinal nematodes and lungworms, where Th2 polarization supports parasite clearance and tissue repair, but may also contribute to fibrosis or chronic inflammation if dysregulated. IL-13 is also implicated in allergic and inflammatory respiratory conditions, mastitis-associated immune modulation, and shaping the Th1/Th2 balance during infections such as bovine viral diarrhea virus (BVDV) and other pathogens. As a biomarker of type 2 immune polarization, bovine IL-13 is relevant in vaccine development, host–parasite interaction studies, and evaluation of immune resilience in production systems. In veterinary and comparative research, characterization of bovine IL-13 supports investigations into mucosal immunity, fibrotic responses, cytokine network regulation, and development of strategies to enhance disease resistance while minimizing inflammatory pathology in cattle.