IMMUNOLOGICAL AND HEMATOLOGICAL CHARACTERIZATIONS OF THE WASTING PIG SYNDROME

After weaning, pigs may develop a wasting syndrome characterized by sl ow growth, decreased disease resistance, and increased mortality. This study was conducted to determine whether differences in immune indice s exist between wasting and normal pigs of a common age. Treatments we re normal controls (N), wasting pigs (WP), and WP treated with the neu roleptic drug amperozide (WPA). Blood samples were taken on the day of treatment (d 0) and 7 and 21 d after treatment. Cortisol concentratio ns and hematological values were measured, and functional immune assay s were conducted on all samples. Body weight was lower (P < .05) for w asting pigs at the start of the study. Wasting pigs and WPA also had f ewer (P < .05) white blood cells, lymphocytes, and monocytes than norm al pigs. The neutrophil:lymphocyte ratio, an index of stress, was grea ter for WP and WPA (.79, .92, and .59 +/- .07 for WP, WPA, and N, resp ectively; P = .008). Functional in vitro immune assays did not differ between groups. Differences in numbers of lymphocytes and monocytes in wasting pigs may result from chronic stress and contribute to the dec reased disease resistance and increased mortality seen in these pigs.