Autumn is the season when respiratory problems are most common in broiler chicken farming. Because of the large temperature difference between day and night, broiler flocks are highly susceptible to cold-induced respiratory problems.
At present, many potential stress factors in broiler farming environments in China can cause respiratory diseases in broiler chickens, reducing their immunity and leading to other concurrent diseases. Clinical signs of respiratory disease in broiler chickens commonly include mucus around the mouth and nostrils, rattling sounds during breathing, and pulmonary edema. In severe cases, coughing up blood can lead to death.
Therefore, understanding the epidemiological characteristics and causes of respiratory diseases, and mastering effective prevention and control measures, are very important for improving the economic benefits of broiler farmers!!
Epidemiological characteristics
One: Respiratory diseases in broiler chickens show some seasonality. They occur most frequently in autumn, winter, and spring, while cases are generally relatively milder in summer. However, the incidence is higher during seasonal transitions and when temperatures fluctuate.
Two: This disease can infect broiler chickens of any age. Some cases are caused by bacteria, some by parasites, some by viruses, and others are mixed or secondary infections.
Three: After a chicken flock is generally infected with this disease, the chicks grow and develop slowly, and broilers of various ages begin to die one after another. In addition, with the vigorous development of the broiler farming industry, this disease has also shown a pattern of recurring old diseases and the continued emergence of new diseases. Causes of the disease
The causes of this disease are relatively complex, mainly involving 3 factors: disease factors, feeding and management factors, and immune factors
1) Disease factors
This disease is not caused by a single pathogen. It is often associated with mixed or secondary infections involving avian influenza H9 subtype viruses, atypical Newcastle disease, Escherichia coli, infectious bronchitis virus, and Mycoplasma.
2)Management factors
①Feed nutrition factors. The quality of feed provided to broiler chickens is poor, and its protein concentration is insufficient, resulting in inadequate immunoglobulin production in the broilers, low disease resistance and stress tolerance, and a high susceptibility to respiratory diseases.
② Rearing environment factors. Nowadays, broilers are often raised in standardized chicken houses. To reduce the effects of temperature fluctuations, such as sudden climate changes in winter and spring and large day-to-night temperature differences, standardized poultry farms mostly use warm-air furnaces for heating and fans to exhaust air and provide ventilation.
3) Immunization factors
Immune vaccines vary in quality, and an unreasonable immunization schedule (doses that are too high or too low, or an insufficient or excessive duration of action), improper immunization methods (changing nasal or eye drops to administration via drinking water), or too many immunizations can all lead to immunization failure. In flocks of chickens with failed immunization, antibody levels in the body are low and antibody persistence is shortened. The immune response is weak, making the chickens susceptible to pathogens that cause diseases such as Newcastle disease and infectious bronchitis, which can trigger respiratory diseases.