For farmers, it is best to breed with boars, which follows the laws of nature. Judging from the mating process, sows will be happier, thus improving the pregnancy rate. The probability of reproductive tract infection in sows is small, but there are individual differences in the breeding process. Try to choose boars with the same size as sows to breed with them. For large-scale pig farms, it is economical to promote artificial insemination and reduce the number of boars, thus reducing the cost of feeding management, so it is also cost-effective.