"The sow farm must not use any medicine containing estrogen, otherwise it will inevitably lead to a decrease in the number of false pregnancies and litter size in sows," said Zhang Shouquan, professor of the South China Agricultural University. Zhang Shouquan introduced that, according to relevant research, estrogens such as estradiol and other analogues (such as zearalenone) will lead to a significant decrease in the amount of pseudopregnancy and litter size in sows. He analyzed that estradiol is a pregnancy signal that is secreted by early embryos, but that estrogens synthesized and secreted by faster developing embryos are harmful to slower developing embryos because estradiol alters endometrial protein secretion and composition. Failing to implant slower embryos. “Taihu pigs have a high number of litters, because early embryos grow slowly, and the amount of estradiol secreted is small, which is conducive to more implantation of embryos.†Zhang Shouquan said that estrogens are abundant in nature and can easily lead to falsehood of sows. Pregnancy signal. “I often appeal on various occasions that sow farms must not use any drugs that contain estrogen, but they are still being recruited.†According to the Southern Rural News, in recent years, feed and veterinary medicines have been increasingly targeted specifically for sows and piglets, and large-scale sow farms have become the focus of the company's development. According to Liu Feng, general manager of Hunan Agricultural University Animal Pharmaceutical Co., Ltd., although the market is getting hotter, the research on sow reproduction in China is far from enough, and it is basically in its infancy. The research on sow reproduction belongs to basic research and it is extremely difficult to break through.