Key points of High-yield Reproductive techniques of Goat

1. Artificial insemination of sheep

Artificial insemination technology refers to the use of equipment to collect the semen of the breeding ram, after treatment and preservation, and then use the equipment to transport the semen to the reproductive tract of the ewe to make it pregnant. Artificial breeding technology can rapidly expand the number of improved breeds and effectively improve the utilization rate of fine bred rams, which is one of the important technologies in modern animal husbandry. The artificial insemination techniques of goats include semen collection and treatment, preservation, estrus identification and timely insemination.

1.1. Semen collection: for the preparation of ram semen used for artificial insemination, first of all, instruments are used to collect semen of breeder ram. At present, false vaginal method is often used to collect semen.

1.2. Ram training: the ram should undergo about a month of training before formal semen collection, including observing mature ram semen collection, being familiar with Taiwan livestock, sperm collectors and sperm collection operation, etc. The ram of 1-5 years old is generally selected for semen collection. Early semen collection is easy to cause damage and affect the growth of the ram and shorten the breeding life.

1. 3. Preparation before semen collection: the instruments should be strictly disinfected before semen collection. the preparation of false vagina requires that the temperature, pressure and lubrication degree of false vagina are all suitable. generally, the temperature of false vagina is 38 ℃-42 ℃, the pressure is triangular when the inner tube is full, and the lubrication degree is that the outer mouth of inner tube is smeared with lubricant.

1. 4. Semen collection operation: when collecting semen, the prepared false vagina will be introduced into the false vagina when the ram climbs across the Taiwan animal, and the protruding penis will be introduced into the false vagina to ejaculate inside to obtain semen.

1. 5. Semen dilution and preservation: the semen collected should be examined by microscope immediately. After determining the dilution ratio, the semen should be isothermal diluted and transferred to cryopreservation. As the artificial insemination of ewes uses cervical insemination, the dilution multiple after semen collection is not easy to be too high, generally 3-5 times is appropriate. At the same time, in order to ensure the success of mating, the vitality of semen used in insemination should not be less than 0.5, so it is determined that the main methods of semen preservation in goats are dilution at room temperature and cryopreservation within one week. it is not suitable to popularize artificial insemination of frozen semen in large quantities (except for preservation or introduction of cherished varieties).

1.6, estrus identification: ewe's estrus is different from other livestock, the characterization is not obvious, it is not easy to find through external observation, so ram estrus test is commonly used to determine estrus. The method is to bind the test cloth to the lower abdomen of the ram to ensure that the ram's penis cannot protrude to mate, and then put it into the ewe herd to find the ewe by sniffing the ewe's vagina and climbing across the steps. The small circle test method should be adopted during the trial, which is helpful to save the physical strength of the ram and reduce the excessive stress caused by the pursuit of the ram. Being crawled by a ram and standing still is a prominent sign of ewe ewe estrus.

1.7. Timely insemination: for ewes, ewes are usually inseminated at the same time of estrus or artificially inseminated after 6-8 hours, and then inseminated again at intervals of 8-12 hours. The methods of estrus in the morning, mating in the evening, estrus in the afternoon and early in the morning are often used in production. Ewes treated with estrus synchronization by estrus control technique can inseminate at the same time 42 hours after drug treatment, and then inseminate again at an interval of 8 hours without testing the ram.

1.8. Artificial insemination: artificial insemination of sheep mainly uses the method of opener or vaginal endoscope. The method is as follows: insert the ewe vagina with an opener or vaginal endoscope, find the external orifice of the cervix by reflector or flashlight light, insert the semen inseminal device into the external orifice of the cervix 1-2cm, inject semen, and then gently remove the inseminal apparatus and the opener.

2. Diagnostic techniques of early pregnancy in ewes.

The combination of early pregnancy placenta (1d-90d) in ewes is not close, and abortion is easy to occur. Early pregnancy diagnosis is beneficial to strengthen the management of pregnant ewes, reduce the abortion of pregnant ewes and improve the reproductive efficiency of ewes. The change of body type of ewe in the early stage of pregnancy is not obvious, and it is not easy to be confirmed by external observation. At present, the main diagnostic methods are estrus observation and B-ultrasonic exploration.

2.1, estrus observation: estrus observation is to reverse the determination of pregnancy by observing estrus. Generally, the breeding ewes without estrus were confirmed as pregnant ewes after 20 and 40 days of mating, which were tested continuously for 3-5 days respectively. The advantage is that it is easy to operate and does not need to go through the instrument. The disadvantage is that the earliest diagnosis is relatively late, two consecutive periods of estrus (about 40 days) are required after mating, and the pregnancy can only be confirmed by non-estrus ewes. In addition, because some ewes will also show estrus after pregnancy, it is easy to be misdiagnosed as non-pregnant, resulting in repeated breeding and even miscarriage caused by the ram chasing and climbing or colliding with the ewe.

2. B-ultrasonic exploration method: it refers to the method of diagnosing pregnancy by probing the fetal development in the abdominal wall or rectum of breeding ewes by B-mode ultrasound. The advantages are that the stress to the ewe is small, the detection results are intuitive and accurate, and the time of pregnancy diagnosis is earlier than the test method. Generally, pregnancy can be diagnosed by finding the pregnancy sac cavity about 30 days after mating, with an accuracy of more than 80%; about 40 days after mating, pregnancy is confirmed by finding cotyledon development, with an accuracy of 100%. The double lamb rate can be further determined by observing the fetus about 50 days after mating; experienced testers can advance the diagnosis of pregnancy to about 18 days after mating. The disadvantages are: the use of hand-held instruments and early detection technology requires some experience; small sheep farms because of low efficiency, the cost of using the instrument is high.

3. High frequency reproduction system of ewe.

3.1. Three births in two years: ewes give birth to lambs once every eight months, which is exactly three times in two years. This system is generally described as a fixed breeding and lambing plan: lambs are generally weaned at 2 months and ewes are mated at 1 month after weaning. In order to achieve the goal of balanced lambing and scientific management in the whole year, sheep can be divided into four groups with staggered lambing intervals of 8 months, so that a batch of lambs will be slaughtered and put on the market every 2 months.

3.2. five births in three years: since half of the pregnancy period of ewes is 73 days, it is one year's one-year pregnancy. The sheep can be divided into three groups. At the beginning of the system, ewes in group 1 gave birth to lambs in stage 1, mating in stage 2, lambing in stage 4, and re-breeding in stage 5; ewes in group 2 gave birth to lambs in stage 2, mating in stage 3, lambing in stage 5, and re-breeding in stage 1; ewes in group 3 gave birth to lambs in stage 3, mating in stage 4, lambing in stage 1 and re-breeding in stage 2. Over and over again, the lambing interval is 7.2 months. For ewes who give birth to one lamb, 1.67 lambs can be obtained in one year, and 3.34 lambs can be obtained if one child gives birth to twin lambs.