The effect of vaccination on the live weight of chickens and the absolute weight of the spleen and gland

Choosing optimal chicken immunization programs is an urgent problem in poultry farming. Studying the morphology of the organs of the chickens' immune system allows you to objectively assess the effectiveness of prevention methods. The article provides data on the effect of multiple vaccinations on the live weight of chickens and the absolute weight of immune defense organs: the spleen and gland of chickens aged 1, 15, 25, 50, 75, 100, and 120 days. One of the leading indicators of the growth of young birds is the dynamics of live weight under the influence of external factors. Identical technological conditions at the beginning of the experiment and the selection of livestock according to the principle of analogs in groups made it possible to assess the effect of vaccination on the chickens' bodies based on live weight indicators. According to our research results, it was established that in chickens of 100- and 120-day-old age, with multiple vaccinations, there is a probable increase in live weight indicators compared to the control group of animals. Our research showed that by 25 days in chickens (vaccinated six times), the hands of the absolute mass of the spleen practically did not change. At the same time, in 25-, 100-, and 120-day-old chickens, there is an increase in the absolute mass of the spleen and the gland at 15- and 50-day-old compared to the indicators of non-vaccinated animals. This indicates the implementation of immune reactions in the studied organs of immune protection due to increased migration of T- and B-lymphocytes to them. In addition, if age periods are compared, a decrease in the absolute mass of the Garder gland was found in 75-day-old chickens compared to 50-day-old chickens, which indicated the involutional processes of this gland. The maximum parameters of the gland's absolute mass were found at 50 days in chickens of both the vaccinated and non-vaccinated groups. Thus, in vaccinated chickens, this indicator of the gland was 0.095 g. Organometric changes in the spleen and gland of vaccinated chickens can be one of the criteria for diagnosing poultry immunodeficiencies.