The decrease in milk production during mastitis in dairy cows is due to pathogens (such as S. aureus and Escherichia coli) that induce hypoxia, oxidative stress, and apoptosis, while suppressing the expression of milk genes (Csn2, Lalba, and Csn1s1) in the mammary gland [49, 50]. The gene discussed is CSN2; the disease is mastitis.