The stillbirth mentioned here refers to the normal individual fetus that died when the sow was giving birth - white fetus. Excluding the mummy and black fetuses formed in the first trimester of pregnancy, the main reason for sows to give births (white fetuses) is that the sows are too prolonged during childbirth. The normal labor process of the sow (from the first piglet to the entire discharge of the entire baby's clothing) is 2.5 to 3 hours, and the birth time of more than 3 hours is considered to be prolonged labor, and prolonged labor can cause death of the piglet at birth. Because the sow shrinks due to the placenta during delivery, the blood flow is not smooth, causing part of the piglets to fall off and the umbilical cord is interrupted. Broken umbilical pigs must be produced within 5 to 10 minutes. If the sows have prolonged labor due to various factors, the umbilical cord is broken. If the piglets are not produced, the piglets will die due to lack of oxygen. According to relevant statistics, the death of the sows caused by the prolonged labor of the sows accounts for 80% to 90% of the total stillbirth.

(1) Causes of prolonged labor in sows

1. When the sow is giving birth, the body condition is too fat or too thin. During pregnancy, feeding high levels of sows for a long time increases the rate of stillbirth in sows. Too much sows can cause over-fertilization, resulting in excessive fat deposition around the uterus, subcutaneous and peritoneal. The sow is prone to fatigue during childbirth, and the time for giving birth is longer. The mortality rate of the piglet is high at birth; but the sow with too weak body condition, due to insufficient productivity during labor, the uterus is weak, and the labor is prolonged, resulting in prolonged labor. Fetal deaths increase.

2, sows eat too much before the birth, so that the sows in the delivery of the intestines are too heavy, the oppression of the fetus causes the piglets to produce difficulties, so that the labor process during childbirth.

3, the summer weather is hot, sows are easy to constipation. Due to constipation, gastrointestinal emptying is blocked for a long time, so that the feces fill the intestines, and the birth canal affects the birth of the fetus. At the same time, the sows suffer from constipation and long-term anorexia, and the body is weak, the birth is weak, the sow is prone to dystocia or the labor process is prolonged, and the stillbirth is easier. occur.

4. In the summer, due to the influence of high temperature, the sow's labor process is generally longer. According to statistics, the sows born in the sows with high ambient temperature from May to October have an average mortality rate of 0.3 to 0.4 per litter per month compared with the lower temperature. The main reason is that the sows caused by high temperature in summer The labor process is extended. Due to the high temperature in summer, the sow is affected by heat stress, and the body secretes excessive stress hormone, adrenaline. Adrenaline causes uterine vasoconstriction, which reduces the oxytocin that reaches the uterine smooth muscle. The uterine muscle does not get enough oxygen, causing the frequency and intensity of uterine contraction to decrease, resulting in prolonged labor.

5, individual primiparous sows because of the first childbirth, stress, often irritability, ups and downs, the body will also secrete excessive amounts of adrenaline, thereby inhibiting the amount of oxytocin reaching the uterine smooth muscle, so that during childbirth The labor process is extended.

6. When a sow is infected with a reproductive disorder or a general high fever, it will cause the sow to have a stillbirth and prolonged labor.

(2) Prevention and treatment measures for pig diseases

1. Control the body condition of the sow during childbirth to prevent over-fertilization or too thin. In actual work, the sow's body condition should be full on the back, with a flat upper line and no bone protrusion. Below the lumbar vertebrae, there should be a dimple in the back of the rib and in front of the pelvis. Therefore, pregnant sows should be restricted to feeding according to the growth and development rules of the fetus and the sows and fats of the sows before 98 days. It should be fully free to eat from 100 days before pregnancy to 3 days before delivery, which can not only improve the birth weight of piglets, but also Prevent sows from getting fat.

2, sows must be limited to feeding before feeding. In order to alleviate the adverse effects of excessive gastrointestinal burden on litter, the sows should start the restriction 3 days before the birth (the pre-production period). The limit of the standard is: 3 kg per day per day on the 3rd day before delivery, prenatal 2 kg per day for 2 days per day, 1 kg per day per day on the first day of delivery. When the sow is delivered, the farrowing meal is not fed, and 0.5 kg is fed again every half day. For example, the sow is born in the morning, and the sow is in the morning. Stop feeding, feed 0.5 kg in the afternoon, give birth in the afternoon, stop feeding in the afternoon, feed 0.5 kg in the morning on the first day after delivery, 0.5 kg in the afternoon, 2 kg per day on the second day after delivery, and 3 days per day after delivery. 3 kg per day, 4 days postpartum - weaning free to eat. That is, the pre-natal limit material is from most to less, and the post-harvest feeding is from less to more to prevent postpartum indigestion in the sow.

3. Prevent sows from prenatal constipation. It is recommended to mix 1% sodium sulphate and 0.5% rhubarb soda powder in the feed 1 week before and after the delivery of the sow, so that the sow feces can be soft and moist, which is conducive to smooth bowel movement. If the conditional pig farm can use lactation better.

4. In summer, it is necessary to strengthen the heatstroke prevention and cooling work of pregnant sows, especially the sows in the late pregnancy and the sows on the upper birth beds. The pregnant sows are kept in limited position, the density is high, and the heat dissipation is difficult, especially in the late pregnancy. Eat more, increase body heat after eating, body temperature increased by about 0.5 °C before eating, reaching 39.5 ° C, when the sow body temperature of 102-110 days of pregnancy maintained this temperature for a long time, the piglet mortality rate increased during childbirth, so when When the ambient temperature reaches 30 °C or above, it is recommended that the pregnant sows in the breeding house be sprayed down for half an hour, and the sows in the delivery room will be flushed to reduce the effects of heat stress on the sows.

5, for the delivery of the childbirth, should be as quiet as possible, especially for the primiparous sows, when the sow is restless, massage the breast can make it quiet, it is very meaningful to promote smooth delivery.

6. After the piglets are dry, the mucus is dried. After drying the coat, it should be placed immediately next to the sow's breasts to feed the milk. Through the piglets constantly sucking the nipples, the sows can be stimulated to secrete oxytocin in the hypothalamus, causing uterine contraction, which not only helps. Successful delivery, shortening the labor process, is also conducive to milk discharge.

7. Do a good job in vaccination to prevent immature infections in sows, and treat sick pigs, especially fever, sows in a timely manner.

(3) Correct use of oxytocin

1. During the delivery of the sow, do not use oxytocin in the case of successful litter size (1 piglet in 10 minutes), but when the next piglet is still not produced within 30 minutes, it is recommended to inject 10 international units immediately. In the case of midwifery, if the piglet is still not produced within 20 minutes after the injection of oxytocin, it is necessary to check whether the sow is difficult to produce, so as to help the child in time.

2, the use of oxytocin should pay attention to 4 points:

(1) Sows whose cervix is ​​not open (ie, the first piglet is not produced) are prohibited.

(2) dystocia sows should be banned, such as pelvic stenosis and narrow birth canal.

(3) Prohibition of overuse: During the delivery process, the dose of one injection should not exceed 10 international units. High doses of oxytocin will cause strong contraction of the uterus, and piglets will be more difficult to produce and die. Postpartum uterus excessive fatigue function瘫痪, easy to cause the retention of fetal clothes caused by metritis.

(4) After the delivery, the injection of 3 to 4 international units of oxytocin to the sow contributes to the complete discharge of the placenta and lochia, thereby reducing the occurrence of metritis.