Prevention and Control Methods and Technical Key Points for Colibacillosis in Broiler Chickens

To prevent and control colibacillosis in broiler chickens, you must first understand what colibacillosis in broiler chickens is and how it occurs.

Colibacillosis in broiler chickens is an infectious disease caused by Escherichia coli. This disease can occur in chickens of different ages, but chicks are more susceptible, especially chicks at 25 to 35 days of age, where it is most commonly seen. Mortality varies greatly depending on rearing conditions.

The environmental hygiene and rearing management of the chicken house are important triggers for this disease. Multiple triggers, such as excessive concentrations of harmful gases such as ammonia and carbon dioxide in the air inside the chicken house, excessive flock density, insufficient feeding space and drinking space for the chickens, vaccination, flock transfer, and nutritional imbalance, can all promote the occurrence of this disease.

Colibacillosis in broiler chickens is prone to mixed infection with other bacterial (viral) diseases. When colibacillosis is infected simultaneously with infectious diseases such as Newcastle disease, infectious bursal disease, and infectious bronchitis, it will bring great difficulties to prevention and control.

Colibacillosis in broiler chickens usually presents as:

1. Dead embryos, septicemia in newly hatched chicks, and omphalitis. After breeder eggs are infected with Escherichia coli, the bacteria multiply in large numbers during incubation, and most fetuses die in the late incubation period or before hatching. Even if they hatch, their vitality after hatching is poor, presenting as poor yolk absorption, abdominal distension, omphalitis, and diarrhea.

2. Airsacculitis. Airsacculitis mainly occurs in broiler chickens from 5 to 12 weeks of age, mostly with a peak onset period at 6 to 9 weeks of age. Sick chickens are listless, have difficulty breathing, and are accompanied by symptoms such as rales and coughing. Necropsy shows cloudy air sacs and thickened sac walls; in severe cases, there is a large amount of white or yellow caseous exudate in the sac cavity.

3. Yolk peritonitis and salpingitis. Mainly occurs in adult broiler chickens; broiler chickens show diarrhea, with albumen- or yolk-like material adhering to the feathers around the anus.

4. Hemorrhagic enteritis. The main lesions are in the digestive tract, especially hemorrhage and ulcers in the small intestinal mucosa. In severe cases, hemorrhage points can be seen on the serosa, and there is hemorrhage in the subcutaneous connective tissue, myocardium, and liver. The thyroid gland and thymus gland are enlarged.

Prevention and control countermeasures for colibacillosis in broiler chickens:

1. Preventive measures. Strengthen rearing management and environmental disinfection. Strictly control the temperature, humidity, and ventilation inside the chicken house, reasonably adjust the rearing density and feeding times according to different seasons, ensure balanced nutrition for the flock, and improve the body's disease resistance. From the arrival of chicks to slaughter, regularly disinfect the chicken house, flock, equipment, and utensils. In particular, the chicken house after slaughter must be fumigated and disinfected, and disinfection should adopt a cross-combined disinfection method. After detection, isolate and cull sick and dead chickens. In particular, clean manure frequently, and use an iodine-containing disinfectant for disinfection with chickens present every day at noon. Sick and dead chickens should be subjected to harmless treatment, and sick chickens should be isolated for treatment.

2. Treatment measures. Treatment principles: through drug sensitivity testing, reasonably select and use highly sensitive drugs; adopt combined application and alternating use of drugs, preferably feeding two drugs plus a traditional Chinese medicine preparation for treatment within one day; identify disease-triggering factors and treat both symptoms and root causes. Escherichia coli maintains a balanced state when the flock is healthy. Only when the flock suffers from other diseases and the chickens are in a subhealthy or diseased state will pathogenic strains multiply in large numbers and cause secondary infection with colibacillosis; add microecological preparations to regulate gastrointestinal pH and inhibit the growth of Escherichia coli.

For flock treatment, select the highly sensitive drugs Kangliqi and Hugankang for combined application. In the morning, use Kangliqi (ingredients: kanamycin sulfate) in drinking water; in the afternoon, use Hugankang (ingredients: lincomycin hydrochloride, spectinomycin) in drinking water; and add probiotics, vitamin A, and vitamin C to the feed throughout the day, and electrolytic multivitamins or quick supplement in the drinking water. After 2 consecutive days of use, the condition was controlled, and after 4 days, the entire flock of chickens recovered.