At the cellular and molecular level, an animal with endometritis always shows increased levels of PMNs; high endometrial expression of pro‐inflammatory cytokines or mediators, such as interleukin 1β (IL‐1β), IL‐6, IL‐8, tumour necrosis factor‐α (TNF‐α); antimicrobial peptides; acute phase proteins; and prostaglandins (Mateus, et al., 2003; Kasimanickam, et al., 2004; Fischer, et al., 2010; Christoffersen, et al., 2012). The gene discussed is TNF; the disease is endometritis.