ABSTRACT

This study was conducted to find the effect of the delayed routine vaccination schedules on growth performance, blood parameters and immunity levels of broilers reared in a humid tropical part of Nigeria. A total of 90 broiler chickens were procured and sorted into three treatments (control, 1 week delay in vaccination and 2 weeks delay in vaccination). The results showed significant differences (P < 0.05) in all growth parameters studied with lower values for broilers with delayed vaccination schedules (Treatment 2 and 3). Shank length and gains in shank length were not significantly (P>0.05) affected by delayed vaccination schedule. The blood parameters (PCV and WBC) values were significantly (P<0.01) lower in birds whose vaccination schedule was delayed for two weeks, (Treatment 3) compared to other treatments while immunity levels were significantly (P<0.01) lower in Treatment 3 compared to Treatments 2 and 1 respectively. It was concluded that delayed vaccination schedule of up to two weeks considerably affected growth performance and immunity status of broilers.