During the same period of estrus, a group of sheep or a local ewes in a natural village are estrus at the same time, which facilitates artificial insemination of sheep and increases semen utilization. At the same time, ewes in the same period, breeding at the same period, lambing at the same time also facilitate the organization and management of production. Once the ram is diluted by one shot, the sperm can be used to infuse 50 to 100 ewes. Under normal conditions, semen storage time does not exceed 3 days. If the ewes are scattered in the estrus, semen collected each time can only use a small part, which not only results in semen waste, but also increases the unnecessary burden and energy consumption of the ram. 1 vaginal sponge suppository The sheep is a practical type of vaginal sponge, which is a progesterone-based sheep estrus preparation. The method of use is easy, the effect is reliable, and the cost is low. It is an ideal practical preparation at present in China. Apply a special lubricant ointment to the sponge plug and place it into the deep vagina of the ewe with a sponge stopper. The nylon traction line on the sponge plug stays 3–4 cm long outside the vagina, and the excess part is cut off. Traction cords should not be left too short to prevent retraction into the vagina and cause difficulty in embolization. And should pay attention to the bent end of the pull line to prevent the end of the tail to stimulate the inner side of the ewes, causing ewes discomfort, in the vagina sponge plug at the same time, subcutaneous injection of estradiol benzoate 2mg, can improve the induction of estrus. After the vaginal suppository is placed in the vagina for 9 to 12 days, the tracheal clips outside the vagina are clamped gently with a hemostatic forceps. If the traction wire breaks or the traction wire retracts into the vagina, use an opener to open the vagina and remove it. Eruption can be performed within 2 to 3 days after the vaginal sponge plug is sprayed. The effective rate is over 90%. However, this method was slightly less effective in the early stages of the estrus season. If the removal of the sponge plug, together with the injection of FSH (follicle-stimulating hormone) 25 ~ 30IU, can increase the estrus effect at the same time and double the lamb rate, but the dose can not be greater than 30IU, otherwise it can cause a reaction. Lactating goats have high levels of prolactin in the blood and inhibit the secretion of gonadotropins. When using a sponge plug to induce estrus, they can cooperate with bromocriptine injection 2mg (dissolved in 4mL of 75% ethanol solution, 2 injections, interval 12h) To inhibit prolactin secretion and promote the secretion of gonadotropins. 2 Prostaglandin treatment Prostaglandins have the effect of dissolving the corpus luteum. For progesterone in the ovary, the corpus luteum dissolves after prostaglandin injection. The inhibitory effect of progesterone secreted by the corpus luteum on the follicles is eliminated, and the follicles on the ovary develop and mature. Sheep estrus, but no effect on the ovary without luteal ewe. Pregnant ewes can cause miscarriage after prostaglandin injection. The entire group of ewe all injected with 15-methyl-prostaglandin (1.2 mg) for the first time. The ovary had a corpus luteum and was estrus within 72 to 90 hours after injection. For sheep that did not respond to the first injection, the second injection was given 10 days later. During this time, these ewes may respond to the second injection due to the formation of corpus luteum in the ovaries of natural estrus. The advantages of this method are convenience. The first disadvantage is high treatment cost. Second, it does not work on ovary without luteal body. Third, it is invalid in non-estrus season. Fourth, erroneous use of pregnant ewes can cause miscarriage. 3 drug buried method In the breeding season, goats were implanted with 6 to 9 days of progesterone vials under the skin and then injected with 10 IU/kg of pregnant gonadotropins. Within 72 hours, the estrus rate of the ewes reached more than 80%, and the lambing rate was increased. 4 oral method Every day, a certain amount of hormone drugs are evenly mixed into the feed and fed continuously for 12 to 14 days. The oral dose of the drug is 1/10 to 1/5 of the vaginal embolization method. The day of the last oral administration, intramuscular injection of 400 to 750 IU of pregnant gonadotropins.