Blue-ear disease (PRRS) is a highly contagious disease in pigs caused by viruses. It has the characteristics of rapid spread, wide incidence, etc., and has caused huge impact on the pig industry in the world. Economic loss.
1 Clinical symptoms
Pig blue ear disease is mainly the infestation breeding system and the respiratory system, and is mainly characterized by the three major characteristics of sow reproductive failure, high mortality of weaned piglets, and high respiratory disease of bred pigs.
1.1 The preterm and preterm sows exhibited high fever (40°C to 41°C), mental depression, anorexia, and dyspnea. A few sows (1% to 5%) had ear, nipple, abdomen, and tail hair. common. After these symptoms occur, a large number of pregnant sows abortion or premature delivery, giving birth to mummified fetuses, stillbirths and sickly piglets, the yield rate up to 80% -100%. Preterm sows do not give birth well, have less milk or no milk.
1.2 Piglets, especially piglets, have a high mortality rate of up to 80%. Clinical symptoms are related to age, and prematurely born piglets die at birth or within days. Most newborn piglets suffer from dyspnea (abdominal breathing), muscle tremor, posterior palsy, ataxia, sneezing, drowsiness, depression, and loss of appetite. Most of the weaned pigs had symptoms of dyspnea, cough and pneumonia after infection. Some pigs developed symptoms such as diarrhea, arthritis, and skin spots.
1.3 The body temperature of fattening pigs can be increased to about 41°C, appetite is significantly reduced or eliminated, most of the body is reddened, breathing is accelerated, and cough is aggravated. Individual pigs have a small amount of mucus nasal fluid. The mortality rate of sick pigs without secondary infection was low.
The symptoms of 1.4 boars were mild and their duration was short. However, the quality of spermatozoa decreased and the spermatozoa were more dead. This is one of the reasons why sow fertility rate declines and return rate increases.
2 Epidemiology
The source of infection of the disease is sick pigs, rehabilitation pigs and healthy pigs. The virus can remain in the recovered pig for at least 6 months (can be continuously detoxified in vitro). The virus can be excreted from nasal secretions, excreta, etc., and transmitted through air, contact, placenta, and mating. When the climate is harsh, high temperature, poor sanitation, and high stocking density increase the incidence of this disease. In recent years, the epidemic features of this disease are mainly characterized by the following five characteristics: First, the clinical presentation tends to be complex and the degree of morbidity is getting worse: Second, the mortality rate of piglets is on the rise; Third, subclinical infections are increasingly common, and the continuity of herds Infections and occult infections are very common. The pigs have a long time of poisoning. The fourth is immunosuppression, often secondary to other diseases (such as eperythrozoonosis, streptococcal disease, salmonellosis, etc.), as well as other vaccines ( Such as porcine vaccine) vaccination effect; Fifth, mixed infection is on the rise.
3 Prevention measures
3.1 Adhere to the principle of self-cultivation and self-sustainability and establish a stable breeding herd, which is not easily introduced. First of all, it is necessary to clarify the epidemic situation of the farm on which the pigs are introduced. In addition, serological tests should be conducted. Negative pigs can be introduced, and the introduction of positive, poisoned pigs is strictly prohibited. After the introduction, appropriate isolation zones must be established and monitoring work must be done. Generally, it takes 4 to 5 weeks for isolation and quarantine. Healthy pigs can be fed in groups. In order to fully realize all-in and full-out farms, large-scale pig farms should at least ensure full-fledged delivery and delivery of both the delivery room and the nursery. Strengthen environmental disinfection, implement belt body disinfection, keep the cleanliness of keeping utensils to reduce breeding density, ventilate, reduce temperature, and improve the environment of the pig house. Adjust diets to feed high-energy diets, green feedstuffs for sick pigs, increase vitamin content 5% to 10%, minerals 5% to 10% (Ca, Se, Mn, etc.), pay attention to amino acid balance.
3.2 Prevent the flow of herds. During the onset of the disease, the sale of the pigs was stopped, pigs from the field were stopped, and the pigs were isolated from treatment. The pigs in the farm should strive to stop or move less, and reduce the spread of the disease.
3.3 carry out emergency immunization work. The blue-ear disease epidemic is often accompanied by the occurrence of swine fever, and there is a significant decrease in the eligible rate of localized swine fever immunity antibodies in the presence of blue-ear disease. Therefore, it is necessary to strengthen the immunization work for swine fever, and farmers on a large scale must be vaccinated in time according to immunization procedures. When vaccinating, it is necessary to ensure the quality. The dose can be increased appropriately. Attention should be paid to inoculation and disinfection to prevent immunization failure or artificial transmission of the disease. In addition, according to the actual situation of each field, we actively carry out immunization work such as foot-and-mouth disease, pig asthma, and pseudorabies in pigs. The scale farms promoted the use of the PRRS vaccine to immunize all sows and boars. The basic immunizations were performed twice, immunized every three weeks, and then immunized once every five months.
3.4 Harmless treatment of carcasses of dead animals. According to the relevant national laws, regulations and rules and regulations, pig farms (households) should promptly adopt deep-seated, incineration and other harmless methods to deal with stillbirths and dead pigs, strictly control the flow of sick pigs, and prevent the spread of the epidemic.
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