Haematological and Gross Pathological Changes in Broilers Experimentally Challenged with Velogenic Strain of Newcastle Disease Virus

Newcastle disease (ND) is a severe and fatal disease of poultry caused by Newcastle Disease Virus (NDV). The disease is of economic and public health importance and has been a threat to the growth of poultry industry. A hundred and twenty day-old broiler chickens were procured from a commercial breeder farm. Glucose, vitamin, antibiotics were administered accordingly. Birds were tested for antibodies to NDV and vaccines were administered accordingly. Feed and water were also provided ad-libitum. Birds were randomly distributed into groups. Experimental birds were challenged at five weeks of age. Blood samples were collected for haematology assay periodically after challenging with NDV. The erythrocyte response in the chickens had varying patterns; there were significant reduction in values of Total Erythrocyte Count, Packed Cell Volume, Hemoglobin count in infected chickens. Monocytes were reduced significantly in the infected birds to 7±0.6% as compared to uninfected birds which had 10±0.9%. There were no significant changes in the Eosinophil and basophil absolute values in both infected and uninfected birds during the course of the study. This study showed that haematological values of broiler chicken significantly differ (p=< 0.05) from uninfected and infected birds with virulent NDV. Generally, there were no significant differences in the profile of the vaccinated birds. Hence the need for vaccination and research towards anti-NDV therapeutic discoveries cannot be overemphasized.