On the question of increasing the susceptibility of gheric chickens to colibacteriosis

The author has experimentally established that the use of virus vaccines for the prevention of viral diseases in gherkin chickens reduces their natural resistance to colibacillosis several times. A challenge infection of vaccinated chickens with E. coli strain № 16-6 at a dose of 0.5•LD50 causes the development of colisepticemia, unlike the controls. The most active depressant of the natural resistance of chickens is the Newcastle disease virus, which reduces resistance to colibacillosis to -7 uer. (conventional units of resistance), that is, 14 times, compared to the control. Gherkin production is generally carried out on small farms free from infectious diseases, adhering to the «Everything is full - everything is occupied» principle, not only for individual poultry houses, but for the entire farm. The overwhelming majority of chickens easily tolerate these conditions for their rearing for 16-18 days. Keeping chickens isolated from the environment and kept indoors prevents the development of infectious processes. Therefore, artificially inducing infections during rearing is undesirable. Therefore, the use of viral vaccines in many cases has significant limitations, as vaccination with viral vaccines provokes the emergence and development of colibacillosis in the flock. The use of sanitary preventive measures is often sufficient for the normal rearing of gherkin chickens. In this article, the author studied the quantitative characteristics of the reduction in chicken resistance to colibacillosis after vaccination with commercial live virus vaccines. It was found that challenge infection of vaccinated chickens with E. coli strain No. 16-6 at a dose of 125,000 CFU/kg body weight (0.5•LD50) caused the development of colibacillosis, unlike the controls.

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