Epidemic characteristics and Countermeasures of Chicken Farm Blight

1 Epidemic characteristics of epidemic disease in current@#@230@#@field

The spread of the disease accelerated. Large-scale chicken is the most significant characteristics of large production scale and the number of chickens. The increase in chicken numbers has led to an increase in the spread of disease among chickens.

Disease resistance decreases. In large-scale chicken farms, in order to give full play to the production potential of chickens, the producers will always make the chickens in a highly tense production state, which will inevitably increase the stress factors of chickens, thus making the endocrine abnormality of sensitive chickens, the disease resistance decline, and some diseases that are not easy to occur under free breeding conditions, such as stress syndrome, become frequent diseases.

The species and quantity of breeding birds introduced from abroad have increased significantly, especially through multiple channels, without knowing the occurrence of diseases in the introduced countries, and lacking effective monitoring means and supporting measures, diseases are introduced at the same time as breeding birds are introduced. In recent years, the newly emerging diseases mainly include chicken infectious anemia, chicken glandular stomach infectious tracheitis, chicken infectious encephalomyelitis, chicken colibacillosis, egg drop syndrome, rhinotracheitis, swollen head syndrome, chlamydia and so on.

The disease appears atypical. Due to the low level of immunity, especially the inconsistent level of group immunity, the original old disease often appears with atypical symptoms and pathological changes-that is, atypical, sometimes even with a new appearance, the most representative of which is bronchitis.

The clinical symptoms of major infectious diseases are diversified. The clinical symptoms of the same disease showed multiple types coexisting, and the correlation between clinical symptoms was very small, and the cross-protection rate after natural rehabilitation was very low. For example, infectious bronchitis has traditional respiratory type, egg production decline type, intestinal type, glandular stomach type and inconclusive type that can cause meat damage. Marek's disease has nerve damage type, skin type, visceral type, eye type and so on many kinds, already has warm subclinical infection to cause the immunity suppression, also has causes the huge loss extremely strong strain to cause the disease and so on.

The same clinical symptom may have multiple causes. Due to the change of pathogen serotype and the emergence of new strains, the invasion scope is expanding continuously, and the clinical symptoms are also diversified, so the symptoms of the same etiology are more complex. Stomach swelling degeneration may be Marek's disease, glandular stomach type infectious bronchitis; encephalitis symptoms may be encephalomyelitis, encephalitis type chicken pullorum, encephalitis type colibacillosis, etc.

A new change in virulence or antigen. In modern chicken production, the virulence of some disease pathogens is constantly increasing, and virulent or super virulent strains appear. Although chickens have been vaccinated, they still cannot obtain protection or their protection is not strong, resulting in immune failure.

The incidence of some bacterial diseases increases, the cure rate decreases, and the harmfulness increases. With the increase of chicken farming scale, the increase of livestock commodity circulation, the aggravation of environmental pollution and the increase of various stress factors, the susceptibility of chickens to bacteria increased, and the occurrence of bacterial diseases increased significantly. At the same time, due to unreasonable long-term drug use, abuse of antibiotics and feed containing antibiotics, the drug resistance of bacterial infectious pathogens in chickens is becoming more and more serious, making it difficult to control bacterial diseases such as colibacillosis, mycoplasma septicemia and infectious rhinitis.

Mixed infection increases, the disease is complicated, and the harm increases. In the epidemic process of livestock and poultry diseases, more than 50% of the diseases were diagnosed as mixed infection or secondary infection. In actual production, the mixed infection types are viral and bacterial mixed infection. Bacterial mixed infection, such as chicken colibacillosis and salmonella mixed infection, bacterial disease and parasitic disease mixed infection, chicken colibacillosis and coccidiosis mixed infection.

2. Prevention measures,

2.1 Strengthen the monitoring and quarantine of major diseases

Do early warning, take appropriate and effective control measures as soon as possible, quarantine breeding farms regularly, eliminate positive chickens. Sampling tests on fertilized eggs, dead embryos and weak and dead chicks at hatching to determine whether there are vertical infectious diseases; proportional sampling tests on commercial farms to understand antibody levels and disease conditions of chickens; regular detection of bacterial content and mycotoxins in the air in the house; antibody level detection according to plan after immunization, and establishment of epidemic registration and reporting system; at the same time, feed entering the farm shall be tested, and feed products produced in epidemic areas shall not be purchased; Strengthen the purification of air quality and regularly detect the air quality of chicken houses.

2.2 Promote advanced feeding management techniques

Large-scale chicken farms should establish a stable breeding system, so that chicken farms at all levels (stock farm, ancestral farm, parent farm, commercial farm) population supply is relatively fixed, in order to reduce the vertical transmission of disease in the breeding system and horizontal transmission;"all-in and all-out" is an important technical measure in large-scale chicken farms, not only to ensure the planning of production, but also conducive to the health of chickens and the control, eradication and purification of diseases; In order to ensure the normal production of chickens, the environment in the chicken house must be effectively controlled, such as temperature, humidity, light, dust, harmful gas concentration and the number of pathogenic microorganisms; large-scale chicken farms in order to pursue high efficiency, often use standardized high-efficiency breeding chickens with fast growth rate and high laying rate. For this reason, it is necessary to supply sufficient high-quality feed and select appropriate feed formula, and implement standardized feeding of chickens according to nutritional standards.

2.3 Take integrated control measures

Formulate standards for disease prevention and control, and strictly enforce sanitation and disinfection systems. Pathogenic microorganisms are ubiquitous in nature. In order to prevent the occurrence and epidemic of diseases, pathogenic microorganisms in living environment must be eliminated to eliminate infectious sources and cut off the transmission route of diseases; scientific immunization should be carried out in a planned and conscious way to enhance the resistance of chickens; drug prevention and control work should be done well. Drug prevention and treatment of diseases should be based on correct diagnosis of diseases, selection of highly sensitive drugs and appropriate doses according to epidemiological laws of diseases and drug sensitivity tests, and correct administration methods for treatment.

2.4 Emergency measures in case of outbreak

Specific emergency measures include the following aspects: ① isolation measures shall be taken immediately in case of suspicious disease during daily inspection or quarantine, and relevant treatment and emergency vaccination scheme shall be organized in time;② in case of severe infectious disease, the scene shall be sealed immediately; report to superior competent department and take corresponding measures;③ dead chickens shall be burned, buried deeply or treated in a centralized manner, and sale and consumption are strictly prohibited; ④ Infected chicken houses, facilities, tools, etc. must be thoroughly cleaned, strictly disinfected and left vacant for a certain period of time before use.