Two weeks before delivery, the sow's breasts gradually expand from back to front, and there is an obvious boundary between the breast base and the abdomen; One week before delivery, the sow's nipples are separated to both sides in a figure of eight; 4 ~ 5 days before delivery, the sow's breasts are obviously enlarged, and the breasts on both sides are bright red, and a small amount of dilute milk flows out when the nipple is squeezed by hand; Three days before delivery, the sow moves steadily and cautiously, the nipple can secrete milk, and the nipple is hot by hand; The day before delivery, the milk was thick and yellow, and the sow's vulva was swollen and loose, with purple color and mucus flowing out of the vulva. 6 ~ 10 hours before delivery, the sow is restless, the vulva is red and swollen, and the grass is the nest. 65438+ 0 ~ 2 hours before delivery, sows show extreme mental anxiety, shortness of breath, wagging their tails, crying, sometimes walking back and forth, sometimes sitting like a dog, frequent urination pain, mucus flowing out of vulva, and nipples can squeeze more milk; If the sow lies down, her limbs are straight, the interval between contractions is getting shorter and shorter, and the whole body is to blame, and amniotic fluid (broken water) flows out of the vulva, and the first piglet will be born soon.