EFFECT OF CLIMATIC STRESS ON THE IMMUNOLOGICAL REACTIVITY OF WEANED PIGS

Weaned pigs exposed daily to either unpredictable draught (experiment 1) or intermittent unpredictable draught (experiment 2) showed differe nt lymphocyte blastogenic responses after mitogenic stimulation with p hytohaemagglutinin (PHA) and concanavalin A (ConA). In both experiment s PHA skin test responses were lower for draught exposed pigs than for control pigs and leucocyte numbers or profiles were altered compared to those of control pigs. Superoxide production and chemiluminescence of porcine granulocytes were similar for draught exposed and control a nimals. Furthermore, serum globulin content did not differ significant ly between pigs in the experimental and control room. The strong incre ase in serum gamma-globulin after the Aujeszky Disease Virus (ADV)-cha llenge was the same for draught exposed and control pigs. The same hel d for the lymphocyte blastogenic response with ADV protein as antigeni c stimulus. The present study shows the effects of climatic stress on immunological reactivity, which may reflect a homeostatic disturbance of the pig's immune system elicited by exposure to unpredictable draug ht.