In recent years, due to a variety of factors, the incidence and mortality of chronic respiratory diseases in chickens have risen significantly, causing the chicken industry to suffer major losses. To this end, the author conducted a detailed investigation of chicken chronic respiratory disease in a chicken breeding base in Ezhou City, Hubei Province. The relevant situation is analyzed as follows.
Incidence
From March to September 2008, Ezhou City has a total of 87 chicken farmers and 211,628 chickens. Among them, there were 16 cases of chronic respiratory diseases, and the number of cases reached 36,873. The incidence rate was 17.4% (see the table below). The disease mainly presents the following four characteristics.
(1) The age of onset is small. Among the diseased chickens, there were 8 households below 4 weeks old, 5 households from 7 weeks old to 12 weeks old, accounting for 87.5% of the total number of affected households. Only two households over 13 weeks old accounted for 12.5%.
(2) The onset of symptoms is heavy. After the onset of chickens, the mental state is poor (eye and respiratory symptoms are obvious), and if not treated promptly, the mortality rate will exceed 50%.
(3) More mixed infections. Of the 16 cases, only 5 were chronic respiratory diseases, accounting for 31.3%, and 10 cases were mixed with E. coli, accounting for 62.5%, and were associated with infectious bronchitis and coccidiosis in 1 case. Accounting for 6.3%, mixed infection accounted for 69.8% of the total number of cases.
(4) Longer cure time. The treatment time of 16 cases was more than 3 days. Among them, 5 households were cured from 3 days to 5 days, and 11 households (including 1 household with innocent treatment) ranged from 6 days to 10 days.
Clinical manifestations
The disease is mainly caused by inflammation of the respiratory tract and its adjacent mucous membranes. In simple infections, the chickens first develop respiratory symptoms and at night they can hear wheezes in the flock. Chicken eyes tears, eyelids are swollen, severe eyes are closed, heads are necked down, and cheese-like objects of varying sizes can be seen in the long course of the eye. In severe cases, oppression of the eye leads to blindness. The sinuses are swollen at the moment, and one or both sides of the sinuses are swollen and the face is swollen (mostly after remission). The common nostrils, mucus secretions, chickens without spirit, poor appetite, and finally died of exhaustion. At the stage of chicks and broilers, the growth and development are hindered, and the incidence of adult chickens affects laying. If infected with E. coli during the course of the disease, the condition is aggravated, the diseased chicken does not eat, the diarrhea, and the mortality of the flock is significantly increased.
Pathological anatomy
The diseased chicken is thin and stunted. Laryngeal, tracheal mucosal swelling can be seen, mucous surface of gray mucus, secretions, often yellow cellulose exudate, a serious visible cheese-like blocking throat crack. There are many changes in the balloon, wall thickening, turbidity, opacity, there are a number of cellulosic exudates. The pericardium is thickened and there is a yellow-white cellulose pseudomembrane on the surface of the liver.
Treatment measures
From the epidemiology, clinical symptoms and pathological anatomy of the disease, it is not difficult to make a diagnosis. In practice, a differential diagnosis is usually made by means of drug treatment, and the condition is promptly treated.
1. Rational use of drugs, according to different situations to choose different drugs.
(1) There are only a few chickens in the flock, and there is no epidemic tendency. Katamycin (a daily intramuscular dose of 20,000 units for adult chickens) and streptomycin (200,000 daily intramuscular doses for adult chickens) can be used. ), once in the morning and in the evening, once every 3 days, the symptoms can usually be eliminated.
(2) After the onset of the flock, the cause of the disease cannot be eliminated in the short term. If there is a tendency to continue to spread, tylosin or doxycycline (therapeutic dose) may be administered in drinking water, or Erythromycin spices.
(3) When mixed with E. coli, it can be treated with doxycycline and tylosin, and the original enrofloxacin or doxycycline powder can be used for water or spices (with therapeutic amount). Day - 5 days, get satisfactory results.
2. Group isolation. When chronic respiratory disease occurs in chickens, the diseased chickens must be separated from healthy chickens in a timely manner, and the sinks, troughs, and utensils must be strictly separated from each other. The disinfectants should be disinfected once a day with 100 toxin and fungicides. (concentration 100-200:1).
3. Improve the environment. To eliminate pathogenic factors in time and optimize environmental conditions. During the transportation of the chicks, they must be transported using standard seedlings and transport boxes to prevent crowding and colds. During the brooding period, heat insulation and ventilation work should be done to prevent overcrowding and poor ventilation; during sudden changes in the weather Next, we must do a good job of moisture-proof, pressure-proof, cold-proof and thieves-proof work to strengthen the nutrition of chickens.
4. Prevent stress. Affected by external conditions, the chicken's stress response can induce and aggravate the disease. In areas where there is a high incidence of diseases, chickens up to the age of 60 days should be immunized with aerosols. In the feed and drinking water, drugs such as doxycycline and Zhiyuanjing should be added (for prevention). For chickens that have developed chronic respiratory diseases, To delay the immunization time, adjust the immunization program to prevent the exacerbation and immune failure.
Discussion and analysis
According to the above methods for prevention and treatment, generally can receive better results. Of the 16 affected households, only 1 had a long course of disease and induced kidney-type infectious bronchitis as a harmless treatment. All other 15 households were cured and the treatment efficiency was 93.4%. From the prevention and treatment of chronic respiratory diseases, we must do the following three tasks to effectively prevent the occurrence of the disease.
Pay close attention to seedling production. Strengthen the breeding and management of breeder chickens, develop programmatic immunization of chickens, and do hatching work to ensure the quality of seedlings.
Conduct technical training. Some cultural professionals have low cultural quality, and lack of necessary knowledge about raising chickens is an important reason for the large area of ​​the disease. Therefore, it is necessary to conduct systematic technical training for farmers and improve their ability to prevent and treat this disease.
Improve management methods. At present, many farmers still use traditional farming methods for breeding, and have poor feeding conditions and poor equipment. Therefore, the use of professional chickens raised for 30 days and then distributed to the hands of farmers, and strengthen technical guidance, can effectively prevent the chicken chronic respiratory disease.
The virus is composed of a nucleic acid molecule (DNA or RNA) with a protein consisting of non-cell morphology of the campal life of the living body. The general symptoms of viral infection are fever, headache, cough and other symptoms of systemic poisoning and viral host and invasion of tissues and organs leading to inflammatory symptoms caused by local symptoms (diarrhea, rash, liver function damage, etc.). Different symptoms of the different virus, some viruses can also damage the myocardium, causing viral myocarditis. There are two types of viral infections, mostly recessive infections (subclinical infections), and a few are dominant infections. Dominant infection can be divided into acute infection and persistent infection. There are many ways of antiviral infection, such as direct inhibition or killing of viruses, interference with virus adsorption, prevent viruses from penetrating cells, inhibit viral biosynthesis, inhibit viral release or enhance host antivirus capabilities. At present, there are several major types of antiviral drugs: Anti-Respiratory virus infection drugs, anti-immune virus drugs, anti-hepatitis virus drugs, anti-herpes virus drugs.
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