What causes the disease when the conception rate of sows is low?

What causes disease? -------------------------------------- Parvovirus disease affects the reproductive performance of sows, mainly depending on which stage the sow is infected with the virus, generally causing sows not to estrus, infertility, abortion, stillbirth, weak fetus, mummification and resulting in reduced number of sows. The infection of empty sows can affect the normal oestrus of sows, and some sows will have persistent non-oestrus; the infection of sows at the early stage of breeding will cause sows neither to return to estrus nor to give birth; the infection of sows at the early stage of pregnancy will cause some embryos to die early and be absorbed by the mother; the infection of sows at the middle and late stages of pregnancy will cause some fetuses to die midway, the fetal water will be absorbed by sows, the abdominal circumference of sows will be reduced, or stillbirth, weak fetus, mummification or a few poor piglets will be produced; Generally, sows are infected after 70 days of pregnancy. Although sows can normally produce some piglets, piglets usually carry virus and become new sources of infection. Parvovirus disease prevention is generally in gilts or sows before breeding immune parvovirus vaccine, each sow 2 ml. Gilts should be re-immunized at 3-week intervals. -------------------------------------- Atypical classical swine fever can cause immune decline in pigs and cause reproductive disorders in sows. Sows infected before 10 days of gestation will cause early embryo death or absorption by sows, and sows will return to estrus or reduce the number of litters; sows infected on 10 ~15 days of gestation will increase the number of stillbirths; sows infected in the middle and late stages of pregnancy will cause fetal death and weak fetus, and fetal growth and development will be poor; sows infected about one week before birth will not affect the survival of piglets, but will affect the growth and development of piglets. To prevent atypical swine fever, gilts or sows should be immunized with swine fever vaccine 15 ~30 days before breeding, with a dose of 2 ~4 doses per sow. -------------------------------------- Japanese encephalitis is mainly transmitted by mosquitoes and flies, and occurs frequently in summer. Boars infected with Japanese encephalitis are mainly characterized by orchitis, hypogonadism and decreased semen quality; sows infected with Japanese encephalitis are prone to acute abortion, and high antibodies in the blood of multiparous sows are characterized by difficulty in mating, abortion and stillbirth. The mortality rate of stillbirth, mummification and newborn piglets of sows exceeds 40%, while that of multiparous sows is about 20%. For the prevention of B encephalitis, breeding boars are generally immunized with B encephalitis vaccine once in spring and autumn, and gilts should be repeatedly immunized once every 3 weeks. Leptospirosis can cause fetal death and abortion in pregnant sows and reduce piglet survival. The latent period of the disease is 1 ~2 weeks. Sows are infected in the first month of pregnancy, and the fetus is generally unaffected. Infected in the second month, it will cause fetal death, sow abortion and mummification. Infected in the third month, it will cause sow abortion, weak litter and reduce the survival rate of piglets. To prevent leptospirosis, sows can be immunized with leptospirosis vaccine before breeding in frequently affected areas, and sows should be vaccinated with multivalent vaccine when the pathogen is not determined. Chlamydia psittaci is generally endemic. The disease can be transmitted by the excreta and secretions of infected pigs and latent infected pigs. The disease can harm pigs of all ages, but it is most sensitive to pregnant sows. The pathogen can penetrate into the uterus through the placental barrier and cause fetal death. General primiparous sows and young sows not only have significant symptoms, but also have relatively high incidence, while multiparous sows generally have no obvious symptoms, only stillbirth. Prevention of chlamydia parrot fever should focus on preventing the introduction of the disease. In endemic areas, chlamydia vaccine should be used from suckling pigs to pigs. Brucellosis This disease easily infects adult boars and adult sows, leading to acute or chronic orchitis and epididymitis in boars; leading to abortion in sows, stillbirth and weak fetus. Prevention of the disease should focus on preventing the introduction of the disease. In the old epidemic areas of the disease, general survey and treatment of breeding pigs should be strengthened, and regular immunization should be carried out. Blue-ear disease (porcine reproductive respiratory syndrome) affects pregnant sows and piglets under 1 month of age. Sows show emaciation, anorexia, blue bellies, miscarriage, premature birth, stillbirth and weak fetuses. Prevention of the disease should focus on preventing the introduction of the disease. Vaccination with blue ear disease vaccine can be carried out before and after weaning of sows, and 3 ml of vaccine can be given to each sow. -------------------------------------- Eperythrozoonosis of pigs of all ages can be infected, sow infected with the disease will cause anemia, emaciation, diarrhea, abortion, stillbirth, low conception rate. To prevent this disease, we should do a good job in cleaning and hygiene in the pigsty in summer, eliminate mosquitoes and flies and their blood-sucking insects, and prevent the transmission of the disease by biting sows by blood-sucking insects. Toxoplasmosis can cause abortion of pregnant sows, stillbirth, weak fetus, and acute postpartum death of piglets.