Comparative Haematology of Chickens and Turkeys Experimentally Infected with a Velogenic Newcastle Disease Virus

Abstract

This study compared the haematological findings in cockerels and turkeys infected with a velogenic Newcastle disease virus. One hundred and twenty day-old birds each of cockerels and turkeys, making a total of two hundred and forty were used for the study. The bird types were randomly divided into four groups each making a total of eight groups. Two groups in each species were vaccinated against NDV with La Sota vaccine at three weeks of age via drinking water. The vaccinated and unvaccinated cockerels and turkeys were inoculated with the velogenic NDV at six weeks of age while the control groups were not vaccinated and not inoculated. Blood samples were randomly collected from five birds in each group for haematological analyses at days 0, 3, 6, 10, 15 and 21 post inoculation (pi). The results showed significant (p < 0.05) reductions in packed cell volume, haemoglobin concentration and total red blood cell count in unvaccinated infected turkeys, but showed significant (p < 0.05) increase in total white blood cell (WBC) and heterophil counts throughout the days of the experiment. The increase in the total white blood cell counts was observed three days pi in the cockerels. There was reduction of lymphocytes in unvaccinated but infected cockerels and turkeys three days pi. The erythrocyte and leukocyte values in unvaccinated but infected cockerels and turkeys were similar. The values were lower than those recorded in vaccinated and infected birds. Thus, vaccination against the disease can ameliorate the adverse effect of the virus on haematological parameters. Vaccination of the birds against velogenic Newcastle disease virus reduced morbidity and mortality.

Keywords: Haematology, Velogenic NDV, Vaccination, Cockerels, Turkeys