In the present study, the high temperature in summer could induce chronic stress in domestic sows (Figure 2), which could decrease the expression of kisspeptin and its neuronal activity (Figure 3 and Figure 4), consequently reducing GnRH, FSH, LH, and folliculogenesis, and occurring summer infertility with lower pregnancy rate (%) and the number of littermates per delivery (Figure 1, Figure 3, and Figure 5). The gene discussed is PLOD1; the disease is Infertility.