Haematological changes of fowl typhoid in plasmid - cured vaccinated and unvaccinated chickens following challenge with Salmonella gallinarum var duisburg

Certain haematological changes of fowl typhoid were studied in plasmid-cured vaccinated and unvaccinated broiler chickens following challenge with S. gallinarum var duisburg. The intensity of anaemia was significantly less in the vaccinated challenged birds indicating a protective action of vaccine on haematological changes. Enumeration of total leucocytes count revealed a significant increase in both the infected groups. In group C (unvaccinated challenged) sudden leucocytosis was observed from day 5 reaching peak at 2 weeks and later there was sudden decline in leucocyte count. Significant leucocytosis was also observed in the vaccinated challenged birds but the values were generally lower than the unvaccinated birds and high leucocyte count persisted for longer periods. A study on differential leucocyte and absolute count of heterophils and lymphocytes revealed that leucocytosis was the result of both heterophilia and lymphocytosis.