With the continuous development of science and technology, using sheep's reproductive physiology principle, the use of advanced technologies such as estrus, frozen semen, superovulation and embryo transfer, and early pregnancy diagnosis during sheep breeding can accelerate sheep breeding and Breeding work has greatly improved the production level and production capacity of the sheep industry.
First, the estrus synchronization technology over the same period is the use of certain hormones to artificially control and adjust the ewe's natural estrus cycle, so that the vast majority of a group of ewes as scheduled to focus on heat within a few days. At the same time estrus is conducive to the promotion of artificial insemination. Especially in scattered mountain areas, it is very convenient to focus on artificial insemination if the sheep can be estrus in a short period of time. At the same time, estrus and concentrated breeding can shorten the mating season and save a lot of manpower and material resources. At the same time, due to the synchronization of mating, it will bring convenience to a series of organization and management, such as the birth of lambs, the turnover of herds, and the mass production of commodity sheep, and will be adapted to the requirements of modern intensive production or factory production. There are two ways of estrus in the same period: one is to promote the degeneration of the corpus luteum and thus reduce the level of progesterone; the other is to suppress the estrus and increase the level of progesterone. The nature and role of the hormones used in the two methods are different, but both are to change the level of progesterone in the ewes and achieve the purpose of estrus synchronization.
(1) Promoting the corpus luteum degradation method The application of prostaglandin PCF (2a) and its analogues dissolves the corpus luteum, thereby interrupting the luteal phase, stopping the secretion of progesterone, and using gonadotropin in combination to cause estrus in the ewes. Prostaglandins F-type and analogues used in estrus in the same period include 15-methyl PGF (2a) prostaglandins and PCF (1) methyl esters. Imported are highly efficient cloprostenol and fluprostinol. Prostaglandin is administered by direct injection into the cervix or muscle. The amount of cervical injection is 1-2 mg; intramuscular injection is generally 0.5 mg. When domestically produced cloprostenol (aka 80996) is used, 2 milliliters of 0.2 mg cloprostenol is injected intramuscularly into the cervix of each ewes and over 90% of the estrus rate is obtained within 1 to 5 days. The effect is very significant. Prostaglandins have little effect on the luteal cytolysis 5 days prior to the estrus cycle, so the prostaglandin treatment has no effect on a few ewes and should deal with these unresponsive sheep for the second time. It should also be noted that since the prostaglandins have the effect of dissolving the corpus luteum, the pregnant ewe will suffer miscarriage due to the reduction of progesterone. Therefore, prostaglandins should be used when it is confirmed that the ewe is empty.
(2) The progestogen treatment method applies progesterone to the ewes to be treated, and uses exogenous progesterone to maintain the progesterone secretion in the corpus luteum, resulting in an artificial luteal phase and estrus synchronization. In order to increase the contemporaneous rate, progesterone treatment is often followed by the use of maternal serum (PMSG) that can promote the development of follicles. It has now been able to artificially synthesize progesterone-like substances in various preparations, mainly including medroxyprogesterone (MAP), megestrol (MA), chloramphenone (CAP), fluroginone (FGA), and 18 methylacetylene. Nornones, 16 methyl megestrol (MGA), etc. The amount of different types of drugs is: progesterone 150 ~ 300 mg; medroxyprogesterone 40 ~ 60 mg; megestrol 80 ~ 150 mg; fluroginone 30 ~ 60 mg; 18 methyl norethindrone 30 ~ 40 mg. These artificially synthesized progestogens have similar functions as progesterone, but their efficiency is often greater than that of progesterone, and there are different dosage forms such as emulsions, pills, and powders. Due to different dosage forms, progestogen administration methods include oral administration, intramuscular injection, subcutaneous implantation, and vaginal embolization. 1. Oral progesterone The daily amount of progestogen drugs is mixed in the feed and is taken by the ewe for 12 to 14 days. Therefore, the daily dosage should be 1/5 to 17 of the aforementioned drug dosage except medroxyprogesterone. /10, and require uniform mixing of drugs and feed, so that the intake is relatively consistent. After oral withdrawal on the last day, 400-750 IU of pregnant horse serum was injected. 2. Intramuscular injections are commonly used for intramuscular injections. Daily injection of a certain amount of drug into the sheep's subcutaneous or intramuscular muscles, stopping for 10 to 12 days. The dosage of this method is easy to control, and it is also more accurate, but it needs to be handled and handled daily, which is troublesome. Domestic production of intramuscular injection "triple hormone" only deal with 1 to 3 days, greatly reducing the operating schedule, more convenient. 3. The vaginal embolism method is to make the suspension of the emulsion or other dosage form of the dosage form into a suspension, and then dip a certain liquid solution with a foam sponge, or apply a silicone rubber on the surface, which comprises a silicone rubber ring containing a certain amount of a progestogen preparation. Suppository, connect the pessaries with nylon thread and stuff them deep into the cervix to the outside of the vagina. The other end of the nylon thread stays in the shade outdoors so that the embolus can be pulled out when the medicine is stopped. Vaginal suppositories are usually removed after 14 to 16 days. They can also be applied for a short period of 9 to 12 days or a long period of 16 to 18 days. However, the progesterone treatment time is too long and it has a certain influence on the conception rate. In order to increase the estrus synchronization rate, 400 to 750 IU of pregnant horse serum can be intramuscularly injected on the day the embolus is removed. 4. Subcutaneous Implantation Methods General pills can be directly used for subcutaneous implants, or a certain amount of progestogen preparations can be placed in plastic tubules with small holes in the wall and buried in the ear with a special implanter. Under the skin, after about 15 days, the drug was taken out, and at the same time 500 to 800 international units of pregnant horse serum were injected. The artificially synthesized progesterone, that is, the prolonged period of action of the exogenous progesterone, will change the ewes' genital tract environment and reduce the conception rate. Therefore, the progesterone may not be planted during the first emotion period after the drug treatment. When the two estrus periods appear, the breeding will be carried out again. This will have a very high estrus synchronization rate, and the conception rate will not be affected.
First, the estrus synchronization technology over the same period is the use of certain hormones to artificially control and adjust the ewe's natural estrus cycle, so that the vast majority of a group of ewes as scheduled to focus on heat within a few days. At the same time estrus is conducive to the promotion of artificial insemination. Especially in scattered mountain areas, it is very convenient to focus on artificial insemination if the sheep can be estrus in a short period of time. At the same time, estrus and concentrated breeding can shorten the mating season and save a lot of manpower and material resources. At the same time, due to the synchronization of mating, it will bring convenience to a series of organization and management, such as the birth of lambs, the turnover of herds, and the mass production of commodity sheep, and will be adapted to the requirements of modern intensive production or factory production. There are two ways of estrus in the same period: one is to promote the degeneration of the corpus luteum and thus reduce the level of progesterone; the other is to suppress the estrus and increase the level of progesterone. The nature and role of the hormones used in the two methods are different, but both are to change the level of progesterone in the ewes and achieve the purpose of estrus synchronization.
(1) Promoting the corpus luteum degradation method The application of prostaglandin PCF (2a) and its analogues dissolves the corpus luteum, thereby interrupting the luteal phase, stopping the secretion of progesterone, and using gonadotropin in combination to cause estrus in the ewes. Prostaglandins F-type and analogues used in estrus in the same period include 15-methyl PGF (2a) prostaglandins and PCF (1) methyl esters. Imported are highly efficient cloprostenol and fluprostinol. Prostaglandin is administered by direct injection into the cervix or muscle. The amount of cervical injection is 1-2 mg; intramuscular injection is generally 0.5 mg. When domestically produced cloprostenol (aka 80996) is used, 2 milliliters of 0.2 mg cloprostenol is injected intramuscularly into the cervix of each ewes and over 90% of the estrus rate is obtained within 1 to 5 days. The effect is very significant. Prostaglandins have little effect on the luteal cytolysis 5 days prior to the estrus cycle, so the prostaglandin treatment has no effect on a few ewes and should deal with these unresponsive sheep for the second time. It should also be noted that since the prostaglandins have the effect of dissolving the corpus luteum, the pregnant ewe will suffer miscarriage due to the reduction of progesterone. Therefore, prostaglandins should be used when it is confirmed that the ewe is empty.
(2) The progestogen treatment method applies progesterone to the ewes to be treated, and uses exogenous progesterone to maintain the progesterone secretion in the corpus luteum, resulting in an artificial luteal phase and estrus synchronization. In order to increase the contemporaneous rate, progesterone treatment is often followed by the use of maternal serum (PMSG) that can promote the development of follicles. It has now been able to artificially synthesize progesterone-like substances in various preparations, mainly including medroxyprogesterone (MAP), megestrol (MA), chloramphenone (CAP), fluroginone (FGA), and 18 methylacetylene. Nornones, 16 methyl megestrol (MGA), etc. The amount of different types of drugs is: progesterone 150 ~ 300 mg; medroxyprogesterone 40 ~ 60 mg; megestrol 80 ~ 150 mg; fluroginone 30 ~ 60 mg; 18 methyl norethindrone 30 ~ 40 mg. These artificially synthesized progestogens have similar functions as progesterone, but their efficiency is often greater than that of progesterone, and there are different dosage forms such as emulsions, pills, and powders. Due to different dosage forms, progestogen administration methods include oral administration, intramuscular injection, subcutaneous implantation, and vaginal embolization. 1. Oral progesterone The daily amount of progestogen drugs is mixed in the feed and is taken by the ewe for 12 to 14 days. Therefore, the daily dosage should be 1/5 to 17 of the aforementioned drug dosage except medroxyprogesterone. /10, and require uniform mixing of drugs and feed, so that the intake is relatively consistent. After oral withdrawal on the last day, 400-750 IU of pregnant horse serum was injected. 2. Intramuscular injections are commonly used for intramuscular injections. Daily injection of a certain amount of drug into the sheep's subcutaneous or intramuscular muscles, stopping for 10 to 12 days. The dosage of this method is easy to control, and it is also more accurate, but it needs to be handled and handled daily, which is troublesome. Domestic production of intramuscular injection "triple hormone" only deal with 1 to 3 days, greatly reducing the operating schedule, more convenient. 3. The vaginal embolism method is to make the suspension of the emulsion or other dosage form of the dosage form into a suspension, and then dip a certain liquid solution with a foam sponge, or apply a silicone rubber on the surface, which comprises a silicone rubber ring containing a certain amount of a progestogen preparation. Suppository, connect the pessaries with nylon thread and stuff them deep into the cervix to the outside of the vagina. The other end of the nylon thread stays in the shade outdoors so that the embolus can be pulled out when the medicine is stopped. Vaginal suppositories are usually removed after 14 to 16 days. They can also be applied for a short period of 9 to 12 days or a long period of 16 to 18 days. However, the progesterone treatment time is too long and it has a certain influence on the conception rate. In order to increase the estrus synchronization rate, 400 to 750 IU of pregnant horse serum can be intramuscularly injected on the day the embolus is removed. 4. Subcutaneous Implantation Methods General pills can be directly used for subcutaneous implants, or a certain amount of progestogen preparations can be placed in plastic tubules with small holes in the wall and buried in the ear with a special implanter. Under the skin, after about 15 days, the drug was taken out, and at the same time 500 to 800 international units of pregnant horse serum were injected. The artificially synthesized progesterone, that is, the prolonged period of action of the exogenous progesterone, will change the ewes' genital tract environment and reduce the conception rate. Therefore, the progesterone may not be planted during the first emotion period after the drug treatment. When the two estrus periods appear, the breeding will be carried out again. This will have a very high estrus synchronization rate, and the conception rate will not be affected.
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