Increasing incidence of anemia among clinically ill Georgia broilers: 1988-89 vs. 1990.

The incidence of anemia in clinically ill Georgia broilers climbed from 66.4% (324/488) during 1988-89 to 80.9% (531/656) during 1990. The incidence of polycythemia fell from 1.6% (8/488) during 1988-89 to 1.5% (10/656) during 1990. Specifically, compared with 1988-89, the 1990 incidence of anemia increased significantly in chicks at age 7 days (P = 0.0002) and 28 days (P = 0.05). We have no certain explanation for this shifting incidence of anemia in clinically ill Georgia broilers. Anemic chicks have plasma that contains virus particles with morphologic characteristics consistent with a virus (chicken anemia agent [CAA]) known to cause anemia in chickens. If CAA is the predominant etiology for anemia in clinically ill Georgia broilers, then our observation could be easily explained. The increasing rate of anemia could indicate a decline in broiler health over time.