The purpose of raising sows is to obtain more piglets, and there are two main indicators for the good reproductive performance of Hengliang sows: the number of weaned pigs per year and the reproductive use of sows per sow.
The factors affecting the reproductive performance of sows include genetics, nutrition, pig disease, environment and management. In recent years, with the rapid development of nutrition technology, research on improving the reproductive performance of sows through nutrient regulation has achieved initial success. Other studies have found that almost all vitamins have a greater impact on the reproductive performance of breeding pigs. The main vitamins that affect the reproductive performance of sows are as follows:
1. Vitamin E: Vitamin E is closely related to reproductive function. It can promote the production of thyrotropin (TH) and adrenocorticotropic hormone (ACTH) and gonadotropin, enhance ovarian function, increase follicles to increase luteal cells, and sow diet. Vitamin E supplementation can not only improve the conception rate, reduce fetal death, increase the litter size, but also enhance the anti-stress ability of piglets, reduce the death of piglets before weaning, shorten the weaning to estrus interval, and improve the boar semen. quality. Studies have shown that the number of litters and the number of litters in the sows fed high levels of vitamin E are higher, and the incidence of mastitis-uterine-milk-free syndrome (MMA) is lower. When the sow lacks vitamin E, the ovarian function declines, the sexual cycle is abnormal, it cannot be fertilized, the embryo is abnormally developed or the stillbirth occurs.
2, folic acid: plays an important role in maintaining the reproductive performance of sows and promoting the early development of the fetus. Its main function is the coenzyme in various enzyme systems, which is involved in the synthesis of sputum, so it is very important for the synthesis of DNA and RNA. In terms of maintaining the stable reproductive function of the sows, the number of litters can be increased; maintaining good lactation and preventing lactation disorders. Studies have shown (Lindemann et al., 1989) that the addition of folic acid to sow diets improves embryo survival and steadily increases litter size.
3, β-carotene: supplementation of β-carotene in sow feed will improve litter size, correct sows quiet estrus and ovulation delay, improve embryo survival rate. Beta-carotene is also associated with the synthesis of lutein, which is insufficient to cause termination of pregnancy. Recent studies have also found that the addition of beta-carotene to boar feed can promote testicular development and improve semen quality. Vitamin A and carotene are easily destroyed by oxidation, especially in the case of moist heat and contact with trace elements and rancid fat.
4, vitamin A: appropriate increase in the amount of vitamin A added to the diet, can increase the number of sow litter and the number of weaned pigs (Antipas, 2003). When the sow lacks vitamin A, the conception rate decreases, and the estrus is abnormal, dystocia, miscarriage, stillbirth, weak fetus, deformed fetus and placenta. Piglets blinking and limb paralysis are prone to pneumonia, diarrhea, etc.; young sows have delayed estrus, affect ovarian development, and have high embryo mortality.
5. Biotin: The main function is to maintain the health of the sow's hoof and prevent scabbing, lameness and sputum. At the same time, it can promote fetal growth and development, reduce fetal death and promote lactation, increase ovulation rate and conception rate of sows, and shorten the weaning to estrus interval. If the biotin content in the diet is less than 330ug, it will cause the stillbirth and the suckling pigs to grow and develop due to insufficient breast milk. The study found that supplementation with biotin can increase the length of the sow's uterine horn by 20%, which in turn increases the space occupied by the fetus in the uterus, which is of great significance for the growth and survival of the fetus.
Studies have shown that 300mg biotin is added to the full price of each ton of sows, and the average number of weaned pigs at 21 days is significantly higher than that of the unimplanted biotin control group. The addition of biotin to the sow diet can prevent the sow from cracking in the winter, significantly reducing the incidence of foot problems in the herd and lameness.
6. Vitamin C: plays an important role in various redox reactions in living cells, participates in the synthesis of sterols in the adrenal cortex, helps relieve stress, and eliminates the adverse effects of high temperature on semen quality. After the boar is fed with vitamin C, the sperm quality is improved; the sow has an increased conception rate. Especially in the summer high temperature or sow before and after childbirth to withstand environmental or physiological stress, and vitamin C has a strong anti-stress effect, can improve the sow reproductive performance by relieving stress. Breast milk is the only source of vitamin C in piglets before 1 week of age. Supplementation of vitamin C to sows during pregnancy and lactation reduces the mortality of piglets before weaning.
7, vitamin B2 (riboflavin): Studies have shown that 4 to 7 days after sow breeding, feeding 100mg / d riboflavin can increase the number of live embryos, embryo survival rate, litter size and litter size. Tilton (1991) confirmed that supplementation of 90-100 mg/d riboflavin to sows in the early stages of pregnancy significantly increased sow littering rates.
8. Vitamin K: Adding 100mg/kg vitamin K3 to the diet of pregnant sows increases the litter size by 5.66%. Adding 100mg/kg vitamin K3 to the diet of lactating sows can increase the weight gain of piglets by 7.78% and the survival rate of piglets by 3.81%.
9. Vitamin B6: Adding 15 mg/kg of vitamin B6 (1 mg/kg of the control group) to the diet of pregnant sows can reduce the interval between weaning and estrus by 1.1 days.
10. Niacin: Add 33mg/kg niacin to the sow's gestational and lactating diets, and reduce the incidence of sow's metritis-mastitis-milk-free syndrome by 30%.
Vitamins are the most vulnerable nutrients. Environmental factors such as high temperature, high humidity, light, trace elements, choline chloride, salt, pH and other factors can reduce the activity of vitamins. Although full-price materials and concentrates are added with vitamins, they are During feed processing and storage, transportation and storage, various trace elements in the feed will accelerate the oxidation of vitamins, especially in summer, when the temperature is high and the humidity is high, and the fat in the feed is most easily oxidized. The destruction of soluble vitamins, coupled with the high temperature and high humidity in summer, can cause stress in pigs. In the case of stress, all pigs, including sows, need more vitamins, especially for vitamin deficiency in pigs. prominent.
In addition, diseases, mycotoxins and other factors will increase the animal's need for vitamins. Diseases and parasitic infections will affect the absorption of vitamins in the intestines of the pigs. The mycotoxins in the feed will interfere with the absorption of vitamins A, D, E and K. . Therefore, pig feed must be supplemented with vitamins.
Sow vitamin supplements account for only 2-3% of the cost of mixed feed, but can achieve good economic benefits. In order to avoid the vitamin deficiency affecting the performance of the sow, additional vitamins can be added to the sow feed during sows, breeding, and during pregnancy. Experts suggest that sows should add extra high-quality multivitamin products 250 ~ 500 g / ton, etc., can significantly improve the reproductive performance of sows.
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