The method of increasing the live litter size of sows

Litter size of sow is an important index to measure sow production performance, which reflects the production management level of the whole pig farm and has a direct impact on the economic benefits of pig farming.

The litter size of sows can be divided into: total litter size, which refers to the total number of piglets born, including stillbirths and mummies; live litter size refers to all live litters except mummies and stillbirths. Effective litter size refers to the number of piglets born alive, except for weak piglets.

To ensure pig farm performance, we must strive to increase the number of live piglets in a litter.

1. Improve the ovulation number and egg quality of sows

Increased ovulatory numbers and good egg quality during oestrus are important for increasing litter size. To improve the number of eggs ovulated and the quality of the eggs, short-term feeding of sows prior to mating is recommended.

Production practice showed that increasing the feeding amount of sows 1~2 weeks before mating and properly improving the nutritional level of diet could increase the ovulation number and litter size of sows. For multiparous sows, weaning to oestrus can be managed to increase sow feed intake.

However, attention should be paid to the nutrition in the diet, because the hormones secreted by the intestine after weaning will interfere with the metabolism of nutrients, when feeding high egg level diet has less effect on the quantity and quality of eggs, while feeding high cellulose content feed can promote sows to eat more feed, and at the same time can eliminate hormones secreted by the intestine.

2. Increased fertility

To improve the fertilization rate, we must first improve the quality of boar semen.

In order to improve the semen quality of breeding boars, we should strengthen the nutrition of breeding boars, pay attention to the supply of protein, vitamins and trace elements in the diet, such as increasing the content of selenium and VE in the diet of breeding boars can obviously improve the quality of breeding boar serum, which is due to selenium and VE have antioxidant effect, which has a great effect on improving sperm motility and ensuring sperm quality.

The protein level in the diet is very helpful to improve the quality and quantity of semen, especially for boars with high semen collection frequency. Therefore, 1~2 eggs can be fed to breeding boars every day during the breeding period of breeding boars. To improve the fertility rate of sow breeding, on the one hand, we should improve the quality of eggs, on the other hand, we should achieve timely breeding, grasp the best breeding time, and adopt scientific breeding methods to improve the fertility rate.

3. Improve embryo survival rate

During the early gestation period, the fertilized eggs are free, and the embryo death and abortion are easy to occur during implantation, and the number of live litters is reduced. Generally in sow early pregnancy, sow intake of excessive nutrients, will cause early embryo death.

Therefore, during the first 2 weeks of pregnancy, it is necessary to control the nutrient level in the diet or reduce the feeding amount to improve the survival rate of embryos. However, if the feed intake of sows is insufficient in early pregnancy, or the nutrient intake is low and unbalanced, it will cause hunger in sows, malnutrition, and affect embryo implantation.

During the early gestation period of sows, the feed can maintain their own nutritional requirements, but attention should be paid to the amount of vitamins and trace elements in the diet. For example, VA has a close relationship with the reproductive performance of sows. VA participates in the development of ovaries, follicle maturation, corpus luteum formation, the perfection of oviductal epithelial cell function and embryo development of sows. Therefore, increasing the level of VA in the diet of fertile sows can effectively reduce embryo death and increase the number of live litters.

In addition, early embryonic development requires increased folic acid levels to maintain rapid embryo differentiation, thereby improving embryo and fetal survival rates and thus increasing litter size. Ensure the quality of feed, it is strictly prohibited to feed moldy feed, because mycotoxins can cause sow abortion or fetal malformation.

In addition to reasonable feeding, in order to improve the survival rate of embryos, it is necessary to strengthen daily management. The purpose is to prevent stress reaction in sows, so the environmental temperature of good sow house should be controlled to avoid heat stress in sows. When heat stress occurs in sows, the development of embryos will be hindered, the number of stillbirths will increase, and the number of live litters will decrease.

In addition, sows should avoid other aspects of stress, such as refueling stress, environmental stress, etc.

4. Increased uterine volume

The capacity of uterus is also the main factor affecting the number of live litters. If the number of ovulation of sows exceeds the capacity of uterus after removing the number of failed fertilization and embryo death, it will limit the growth and development of embryos.

Uterine volume is determined by genetic factors, but it is also affected by the interaction between uterus, placenta and fetus, which all affect the survival of embryo during pregnancy. Uterine blood and uterine protein are the two main uterine factors affecting uterine volume. Placenta size and nutritional rotation efficiency are placental factors affecting uterine volume. Fetal red blood cell production and fetal nutrition are fetal factors affecting uterine volume. As the number of fetuses increases, Compensatory behavior can arise from these factors.

In addition, sow constipation will increase intestinal pressure on the uterus, affecting uterine blood flow and blood flow distribution, especially in the late pregnancy of sows, more serious, embryo death, dystocia and other phenomena can lead to a decrease in the number of live piglets, therefore, sows in pregnancy to prevent constipation, can be improved by increasing the level of dietary cellulose to improve constipation phenomenon, improve fetal survival rate.

5. Do a good job in sow delivery

Do a good job of sow delivery work to reduce the phenomenon of stillbirth. If the sow has a long labor, it will cause asphyxia and death of the fetus, which will reduce the number of piglets born.

There are many reasons for dystocia, including large fetus, weak sow delivery, etc., so we should prevent dystocia from happening in sow from many aspects. Sows should avoid too large fetus in late pregnancy, and at the same time ensure proper nutrition and exercise amount of sow, so as to ensure strong uterine contraction during sow delivery.

When the sow gives birth, try to let it give birth by itself. The delivery personnel should do a good job of observation. If difficult labor is found, timely midwifery should be adopted. The fetus should be well nursed after delivery. If there is fake death, the piglets should be rescued in time to reduce the number of stillbirths.