Judging pregnancy by the estrous cycle and external signs

First, judge by the estrous cycle. Generally, after a sow is mated during estrus, if she does not come into estrus again after one estrous cycle (18 to 25 days), we can make a preliminary judgment that the sow is already pregnant. This is especially accurate for sows whose estrous cycles were normal before mating. Second, judge by the sow's external signs. After mating, a sow that shows greediness for food, sleeps a lot, regains body condition quickly, is docile in temperament, moves cautiously, has a glossy coat that lies close to the body, a gradually enlarging abdominal girth, a dry vulva drawn into a line, and a drooping tail. If after another 18 to 25 days the sow still does not show estrus, it can be determined that the sow is already pregnant.