The use of estrus induction, estrus synchronization and timed insemination in cows is of great significance to improving the reproduction rate of livestock. Induced estrus can make young cows of appropriate age who are not in estrus, multiparous cows who have not been in estrus for a long time after giving birth, and cows with ovarian diseases estrus and breed. Regular observation of cows with B-ultrasound can achieve normal conception and calving. Timed insemination can concentrate the estrus time of cows, save the estrus identification link, prevent the phenomenon of missed breeding caused by latent estrus, facilitate centralized insemination, and reduce labor intensity. The implementation of the above methods can improve the reproductive capacity of cattle, reduce the empty rate, and improve the breeding efficiency and social benefits of cattle. B-ultrasound for cattle plays a great role in this.

The principle of inducing estrus is to use gonadotropin (GnRH) or gonadotropin to promote follicle development and estrus. For example, injection of GnRH, "Promoting ovulation No. 3" (LHRH- A3), pregnant mare serum gonadotropin (PMSG), follicle-stimulating hormone (FSH), and human chorionic gonadotropin (HCG) can make follicles develop, mature, and ovulate. This method is suitable for cows with dormant ovaries. You can use cattle B-ultrasound to check first to determine their condition before taking any action; second, use hormones that can dissolve the corpus luteum to promote the dissolution of the corpus luteum, and then develop follicles and cause estrus, such as prostaglandins (CPG) and cloprostenol. This method is suitable for cows with ovarian corpus luteum or corpus luteum cysts, and you can also use cattle B-ultrasound to check and then judge; third, use progesterone to stimulate follicle development through negative feedback and cause sick cows to estrus. Continuous application of progesterone, such as progesterone, for a certain period of time will cause an artificial luteal phase, and then stop the medication, causing pituitary negative feedback and stimulating estrus. After the cattle B-ultrasound examination, the cow is normal, and this method is mainly suitable for cows with periodic corpora lutea.