Porcine reproductive retardation diseases are mainly characterized by the occurrence of abortions, stillbirths, mummy pregnancies in pregnant pigs, infertility in the production of non-viable pigs, deformed infants, infertility in young piglets, and male and female pigs. With the large-scale development of the aquaculture industry, pig reproductive diseases have become one of the most important diseases in large and medium-sized farms. According to investigations, the porcine reproductive disorder in China is mainly caused by viruses. The following is a brief description of several reproductive diseases: 1. Porcine reproductive and respiratory syndrome This disease, commonly known as “blue ear disease,†is a new disease caused by the porcine reproductive and respiratory syndrome virus. It is mainly manifested in anorexia and temperature rise in infected pigs. High (40～41°C), premature delivery during pregnancy, miscarriage in the third trimester, stillbirth, weak and mummy. The disease spreads quickly and has a wide spread. It has spread throughout North America and most European countries. There is no visible pathological change in the disease. Confirmation is generally based on the use of porcine alveolar macrophages or passaged cell lines for virus isolation. Peroxidase assays, ELISA assays, and serum neutralization assays can also be used to detect antibodies. Strengthen pig sanitation and disinfection, strengthen isolation from the outside world, conduct regular serological tests, and strict quarantine and isolation of purchased pigs are important measures to prevent the occurrence of the disease. Vaccines have been applied abroad, inactivated vaccine immunization sows twice a year, each interval of 21 days, attenuated vaccine is limited to 3-18 weeks of age piglets. China's Hakka Research has developed inactivated vaccines, the effect of which is the same as that of foreign countries and is currently being tested in some regions. The disease belongs to the herd, and the epidemic area should adopt early synchronized weaning to isolate the piglets before they become infected and cut off the transmission route from pigs to piglets. Outbreaks of the swine herd must be followed by appropriate supportive care. In addition, it is necessary to strengthen feeding and management and improve hygiene conditions in pig houses, increase vitamins and minerals and other nutrients in the diet, feed high-energy feeds, keep indoor air circulation and pay attention to insulation. 2. Pseudorabies in pigs This disease is an acute infectious disease caused by pseudorabies virus in livestock and various wild animals. The symptoms of swine infection vary with age, and adult pigs only show slower growth and show mild symptoms. Breeding pigs show infertility. Boars swell, shrink and lose sexual function. Sows are returning and are often infertile. Pregnant sows show miscarriage, stillbirths and mummy. Piglets show high fever, loss of appetite, difficulty breathing, and convulsions to death after mental symptoms. The piglet mortality at 15 days was 100%, and the weaned piglet mortality was 10% to 20%. Pseudorabies is widely prevalent in the world. The disease mostly occurs in the cold season, and other seasons also occur. In pigs, the virus is spread mainly through nasal secretions and can also be transmitted through vaginal secretions and placenta. Virus isolation is a reliable method for diagnosing pseudorabies. The use of immune agar diffusion test, ELISA test, neutralization test and hemagglutination inhibition test to detect antibodies can all be used to diagnose pseudorabies. Currently, there is no treatment for pseudorabies. Immunization methods have been commonly used in foreign countries. Inactivated vaccines are used to vaccinate male and female pigs twice a year. After the first immunization, the immunizations are repeated 6 weeks apart. After each immunization, the finishing pigs are immunized every 6 months. After immunization milk can be. China also has pilot tests for illicit pseudorabies and inactivated vaccines in some regions. At present, it is considered that pigs are the main carriers, so pigs and cattle must be kept separately. When introducing pigs, strict quarantine should be adopted. A strict disinfection system should be established to eliminate the insects and strengthen the management of feeding. For farms with this disease, measures should be taken to stop production. After serological inspection, pigs with more than 50% of positive pigs should be eliminated. For four consecutive blood tests, positive pigs with a rate of less than 1% were eliminated. Establishing comprehensive prevention and treatment methods such as purifying pigs is an important measure to control the disease. Third, the porcine parvovirus disease caused by the porcine parvovirus, which is characterized by pregnant pigs infected in the early pregnancy, causing miscarriage, stillbirth, embryo death, mummification of the fetus. In the 30th to 50th day of pregnancy, infected pigs mainly produce mummified fetuses. More than 50 to 60 days of infection appear dead. Abortion symptoms occur in 70 days of pregnancy. The sows that are infected after 70 days of pregnancy are normally farrowing, but these piglets often have antibodies or viruses. In addition, the production of weak, abnormal sows in estrus, long with infertility are the clinical symptoms of the disease. With the exception of pregnant sows, other types of pigs have no clinical symptoms after infection. The porcine parvovirus disease is endemic or sporadic, which occurs mainly in spring and summer or during the period of sow farrowing and mating. In the farm where the disease occurs, reproductive failure can continue for several years or even more than ten years. The mortality rate of sows in early pregnancy caused an embryonic mortality rate of 80% to 100%. Other pigs generally did not die. The lesions can be seen with the naked eye, and the sow's endometrium is inflammatory, the blastoderm is thawed, and the fetus is dissolved and absorbed in the uterus. Virus isolation and the use of serum neutralization tests, hemagglutination inhibition tests and other detection antibodies can diagnose parvovirus infected pigs. For uninfected pig farms, the introduction of poisoned pigs should be eliminated and boar semen should be strictly inspected. Negative pigs can be used. Onset farms should specifically prevent gilts from becoming infected when their first child is conceived, or delay the mating period until 9 days of age when the maternal antibody has disappeared and the autoimmunity is stable. In recent years, it has been recognized that the use of vaccines is a reliable way to prevent the disease. Young sows are generally immunized twice. Our country has already applied the products of pilot test.