How to shorten the labor process of sows?

The stillborn fetus mentioned here refers to the normal individual fetus that dies during the delivery of the sow-white fetus. Excluding mummies and black fetuses formed in the first and second trimester of pregnancy, the main reason for stillbirth (white fetus) in sows is that the labor process of sows is too long during delivery. The normal stage of labor of sows (from the beginning of the first piglet to the complete excretion of the whole placenta) is 2, 5-3 hours, and the delivery time of more than 3 hours is regarded as prolonged labor, which will lead to the death of piglets at birth. Because the placenta of the sow shrinks and the blood flow is not smooth during delivery, the placenta of some piglets fall off and the umbilical cord is interrupted, and the navel-severed piglets must be delivered within 5-10 minutes. If the labor process of the sows is prolonged due to various factors, and the navel-severed piglets are not produced for a long time, the piglets will die of hypoxia. According to relevant statistics, 80% of the dead piglets died due to the prolonged labor process of sows.

The cause of prolonging the stage of labor in sows

1. Sows are too fat or too thin during delivery. During pregnancy, high-level feeding of sows for a long time will increase the rate of stillbirth of sows, because excessive eating of sows will lead to overweight, resulting in excessive fat deposition around the uterus, subcutaneous and peritoneum, and sows are prone to fatigue during childbirth. It takes a long time to give birth and the mortality rate of piglets is high at birth. But too thin sows, due to lack of labor, uterine contraction weakness, but also easy to prolong the stage of labor, resulting in an increase in fetal death.

2. Sows eat too much before delivery, resulting in heavy intestinal burden during delivery, pressing the fetus, causing difficulty in piglets' production, and prolonging the process of delivery.

3. Sows are prone to constipation because of the hot weather in summer. Due to constipation, gastrointestinal emptying is blocked for a long time, which fills the intestinal tract and oppresses the birth canal to affect the birth of the fetus; at the same time, sows do not eat food for a long time because of constipation, weak physique, weak delivery, sows are prone to dystocia or prolonged labor, and stillbirth is more likely to occur.

4. Due to the influence of high temperature in summer, the labor process of sows is generally longer. According to statistics, the stillbirth rate of piglets delivered by sows from May to October is 0, 3-0 and 4 higher per litter than that in months with lower ambient temperature. the main reason is that the labor process of sows is prolonged due to high temperature in summer. In summer, due to high temperature, sows are affected by heat stress and secrete too much stress hormone-epinephrine. Adrenaline causes uterine vasoconstriction, which reduces the amount of oxytocin reaching the uterine smooth muscle and does not get enough oxygen to the uterine muscle, resulting in a decrease in the frequency and intensity of uterine contraction and a prolonged delivery time.

5. Due to the first delivery, individual sows are stressed, often restless, restless, and secrete a large amount of epinephrine in the body, thus inhibiting the amount of oxytocin reaching the uterine smooth muscle and prolonging the stage of labor.

6. When sows are infected with reproductive disorders or general febrile diseases, it will cause stillbirth and prolong the stage of labor.

Prevention and control measures

In order to reduce the stillbirth rate of piglets during sow delivery, it is necessary to prevent the prolongation of sow labor and shorten the litter time as much as possible. Strengthen feeding management and prevention in production.

1. Control the body condition of sows during childbirth to prevent being too fat or too thin. In practical work, the body condition of sows during delivery should be plump on the back, with a flat upper line, without any bone protruding, below the lumbar spine, behind the ribs and in front of the pelvis, and there should be no lacunae for overfattened sows. Therefore, pregnant sows should be restricted according to the law of fetal growth and development and fat status of sows before 98 days, and feed freely from 100 days of pregnancy to 3 days before birth, which can not only increase the birth weight of piglets, but also prevent sows from being overweight.

2. Sows must be fed with limited feed before delivery. In order to reduce the adverse effects of overweight gastrointestinal burden on litter, sows should begin feed restriction 3 days before parturition (whichever is due). The feed restriction criteria are as follows: 3 kg per day on the 3rd day before delivery, 2 kg per day on the second day of prenatal birth, 1 kg per day on the first day of prenatal birth, no feeding for sows during delivery, and 0 or 5 kg of feed every other half day, such as sows giving birth in the morning and stopping feeding in the morning. Feed 0,5kg in the afternoon, give birth in the afternoon, stop feeding in the afternoon, feed 0,5kg in the morning on the first day after delivery, 0,5kg in the afternoon, 2kg per head per day on the second day after delivery, 3kg per day on the third day after delivery. 4 days postpartum-weaning feeding freely. That is, prenatal feed restriction from more to less, postpartum feeding from less to more, in order to prevent postpartum indigestion in sows.

3. To prevent prenatal constipation in sows. It is suggested that 1% sodium sulfate and 0% and 5% rhubarb soda powder should be mixed into the feed one week before and after delivery of sows, which can make sow feces soft and moist, which is conducive to smooth defecation. It is better for pig farms with conditions to use lactation.

4. In summer, the heat prevention and cooling work of pregnant sows should be strengthened, especially in the late stage of pregnancy and parturient sows on the delivery bed. Pregnant sows are reared in limited positions, with high density and difficulty in heat dissipation, especially in the late stage of pregnancy, the sows eat more, the body heat increases after feeding, and the body temperature increases by about 0,5 ℃ compared with that before feeding, reaching 39,5 ℃. The stillbirth rate of piglets increases during delivery, so when the ambient temperature is more than 30 ℃, it is recommended to spray the pregnant sows in the breeding house at an interval of half an hour so as to reduce the effect of heat stress on the sows.

5. For the delivery house that is giving birth, it should be kept as quiet as possible, especially for the first-born sows. When the sows are restless, breast massage can calm them down, which is of great significance to promote smooth delivery.

6. after the piglet is born, dry the mucus and dry the coat, immediately put it next to the breast of the sow to suck the nipple, which can stimulate the hypothalamus of the sow to secrete oxytocin and cause uterine contraction, which is not only conducive to smooth delivery and shorten the stage of labor, but also conducive to milk excretion.

7. Do a good job of vaccination, prevent reproductive disorders of sows, and treat sick pigs, especially feverish sows in time.

Correct use of oxytocin

The prolongation of labor caused by various reasons can be solved by the correct use of oxytocin.

1. During the delivery of sows, do not use oxytocin in the case of smooth delivery (giving birth to a piglet within 10 minutes), but when the next piglet is not produced at an interval of 30 minutes, it is recommended to immediately inject 10 international units of oxytocin to assist delivery. If the piglets are not delivered within 20 minutes after injection of oxytocin, it is necessary to check whether the sows are difficult to give birth in order to assist in delivery in time.

2. Four points should be paid attention to when using oxytocin

Sows where the cervix of ① is not opened (i.e., the first piglet is not produced) are prohibited.

② dystocia sows should be prohibited, such as narrow pelvis and narrow birth canal.

Excessive use of ③ is prohibited: in the process of delivery, the dose of one injection should not exceed 10 international units. High-dose oxytocin injection will lead to strong uterine contraction and spasm, piglets are more difficult to produce and die, and postpartum uterine fatigue and paralysis can easily cause uterine inflammation caused by placenta retention.

After ④ delivery, injecting sows with 3-4 international units of oxytocin contributes to the complete excretion of placenta and lochia, thereby reducing the incidence of uterine inflammation.