These included genes and QTLs related to somatic cell count and mastitis (CACNA2D1, SEMA5A, NEGR1, PTK2B, CTNNA3) (Sugimoto et al. 2006; Deb et al. 2013; Yang et al. 2019; Mohammadi et al. 2022; Wagner et al. 2023), gastrointestinal parasites (PTK2B) (Thorne et al. 2023), and various viral or bacterial diseases. The gene discussed is PTK2B; the disease is mastitis.